JPH0812390B2 - Silver halide photographic emulsion - Google Patents

Description

The present invention relates to photography. More particularly, this invention relates to photographic emulsions containing silver halide grains.

[Conventional technology]

Photography of silver halides has been carried out for over a century. The radiation-sensitive silver halide composition originally used for imaging was named an emulsion because it was initially understood that there was no solid phase present. It has long been known that radiation-sensitive components exist in the form of dispersed crystallites (typically referred to as particles),
The term "photographic emulsion" is still used.

For many years silver halide grains have been the subject of intense research. High iodide silver halide grains containing at least 90 mol% iodide, based on silver, are known and suggested for use in photography, but in practice photographic emulsions almost always require small amounts of iodide. Optionally containing silver bromide, chloride, or a silver halide grain composed of a mixture of chloride and bromide. Up to about 40 mol% silver based iodide can be accommodated in the silver bromide crystal structure without observing a separate silver iodide phase. However, in practice silver halide emulsions containing more than about 15 mol% iodide are rare,
The most common are those containing significantly less than 10 mol% iodide. All silver halide grains, except the rarely used high iodide silver halide grains (which are not taken into consideration in the following description, unless otherwise specified), exhibit a cubic crystal lattice structure.

It has been recognized for many years that the surface area to grain volume ratio of silver halide grains is not constant. The finer the silver halide grains, the greater the grain surface area to grain volume (which is more commonly indirectly
ating coverage), for example, g / m ^{2 of} silver]. Increasing the surface area to particle volume ratio of silver halide grains (hereinafter referred to as the grain surface area ratio) is a function of photographic performance that depends on surface action, such as interaction with processing agents as well as adsorbed additives such as spectroscopic It may be advantageous in improving the interaction with the sensitizer.

However, very fine grain emulsions with the highest surface area ratios, such as Lippmann emulsions, exhibit low photographic speed and are therefore usually not used to form latent images in silver halide emulsions. Within the range of silver halide grain sizes that normally appear in photographic elements, the maximum sensitivity obtained with optimum sensitization increases linearly with increasing grain size. Thus, radiation-sensitive emulsions meet the objective of photographic speed, which requires larger grain sizes, and
It has often represented a compromise between increasing grain surface area ratios, and thus meeting other performance criteria which would benefit from the choice of finer silver halide grains.

Various regular and irregular grain shapes were observed in silver halide photographic emulsions. The grains may show rounded corners and edges due to the lower activation energy for solubilization of silver halide at these positions, but in general silver halide grains are polyhedral and well defined. It is bounded by a crystal plane.

Silver halide prefers the formation of cubic or octahedral crystallographic planes. Silver chloride strongly prefers the formation of cubic crystal faces. Silver bromide also prefers the formation of cubic crystal faces, but in the presence of excess bromide ions it prefers the formation of octahedral crystal faces. Iodine ions in the crystal structure tend to increase the proportion of grains with octahedral crystal faces. Factors that cause the proportion of one crystallographic form to be higher than that of another are discussed in the following literature: James, Photographic Processing.
Logical (The Theory of the Photographic Process) , fourth
Edition, Macmillan, New York, 1977, 9
8-100 pages.

Regular silver halide grains bounded by cubic crystal faces are cubic in appearance when examined by electron microscopy. The regular cubic particles (1) are shown in FIG. The cubic grain is surrounded by six identical crystal faces. In the photographic literature, these crystal planes are commonly referred to as {100} crystal planes, with reference to the Miller indices used to represent the crystal planes. Although the representation of the {100} crystal planes is most commonly used in connection with silver halide grains, these same crystal planes are sometimes referred to as {200} crystal planes. This difference in display results from the difference in the definition of the basic units of the crystal structure. Although cubic crystal shapes are easily visually identified in regular grains, in irregular grains the cubic crystal faces are not necessarily square. In more complex shaped grains, the presence of cubic crystal faces can be ascertained by a combination of visual inspection and the 90 ° angle of intersection formed by adjacent cubic crystal faces.

The practical importance of cubic crystal faces is that they represent the unique surface arrangements of silver and halogen ions, which surface reactions and grain surface reactions typically encountered in photographic applications. Affects adsorption. This theoretically deduced unique surface arrangement is shown schematically in FIG. Here, the small spheres (2) represent silver ions,
On the other hand, the large sphere (3) displays bromide ions. Although expanded, the relative sizes and locations of silver and bromide ions are accurately represented. If the chloride ion is replaced with a bromide ion, the chloride ion will be smaller than the bromide ion, but the relative configuration will remain the same. There are multiple parallel rows, indicated by line (4), each row being formed by alternating silver and bromide ions. In FIG. 2, a portion of the next layer of ions lying below the surface layer is shown to illustrate the relationship of ions to the surface layer.

In another form, the ordered silver halide grains are octahedral in appearance when viewed under an electron microscope. Regular octahedral grains (5) are shown in FIG. Octahedral grains are surrounded by eight identical crystal faces. These crystal faces are called octahedrons or {111} crystal faces. Although the shape of octahedral crystals is easily visually identified in regular grains,
In more complex shaped particles, the presence of octahedral crystal faces can be ascertained by visual inspection in combination with the 109.5 ° angle of intersection formed by the adjacent octahedral crystal faces.

Ignoring any possible adsorption of ions, the octahedral crystal faces differ from the cubic crystal faces in that the surface layer of the ions can theoretically be assumed to consist entirely of silver or halogen ions. FIG. 4 is a schematic representation of a {111} crystal plane similar to that of FIG. 2, where the small spheres (2) represent silver ions, while the large spheres (3) represent bromine ions. Although silver ions have been shown to be present at all available lattice positions on the surface, the presence of silver ions only at every other available lattice position in the surface layer of atoms can lead to surface charge neutralization. It was suggested that it would be more relevant. Instead of a surface layer of silver ions, the surface layer of ions can alternately be bromide ions. The ionic layer just below the surface silver ions consists of bromide ions.

When comparing FIGS. 18 and 2 with FIGS. 3 and 4, both the cubic and octahedral grains have exactly the same cubic crystal lattice structure, and thus exactly the same silver grain. It is important to note that there is an internal relationship between ions and halogen ions. The two types of particles differ only in the crystal planes of their surface. In the cubic crystal plane of FIG. 2, each silver ion on the surface is in close proximity to five adjacent halogen ions, while in FIG. 4 each of the octahedral crystal plane silver ions has only three halogen ions. Note that it is adjacent to the ion.

Silver halide does not like the formation of the five remaining feasible crystallographic forms of the cubic crystal lattice material. In a few cases, silver halide grains with orthorhombic dodecahedral faces were observed. The crystal planes of the orthorhombic dodecahedron morphology in silver chloride and silver chlorobromide emulsions are
aes) et al., U.S. Pat. No. 3,817,756. Wa
From Wyrsch, 1978 International Conference on Photoscience
Paper (Papers from the 1978 International Congress o
f Photographic Science) , Rochester
New York, pp. II-13, page 122 reports an orthorhombic dodecahedral silver chloride emulsion prepared by the triple jet precipitation method in the presence of divalent cadmium ions and ammonia. Berry, “Surface Structure and Reactivi
ty of AgBr Dodecahedra), Science and Engineering of Photography (P
hotographic Science and Engineering) , Vol.19, No.3,5
March 16, 1975, pp. 171 and 172 exemplify silver bromide grains having crystallographic faces of the orthorhombic dodecahedron crystallographic morphology.

Regular orthorhombic dodecahedron grains (7) are shown in FIG. The orthorhombic dodecahedron grains are surrounded by 12 identical crystal faces. These crystal faces are called orthorhombic dodecahedrons or {110} (or less commonly silver halide grains, {220}) crystal faces. The crystal shape of orthorhombic dodecahedrons is easily visually identified in regular grains, but in grains of more complex shape, the presence of orthorhombic dodecahedron crystal faces is , Can be confirmed by a combination with the measurement of the intersecting angle of the adjacent orthorhombic dodecahedron crystal faces.

The orthorhombic dodecahedron crystal faces can be theoretically estimated to consist of alternating rows of silver and halogen ions. FIG. 6 is a schematic diagram similar to FIGS. 2 and 4, where the surface layer of ions is a repeating pair of parallel rows of silver and bromide ions, indicated by lines (8a) and (8b), respectively. Is formed by. In FIG. 6, a portion of the next layer of ions underlying the surface layer is shown to illustrate their relationship to the surface layer. It should be noted that each surface silver ion is immediately adjacent to the four halogen ions.

There are four additional crystallographic forms that can be represented by the cubic crystal lattice structure, but none have been previously reported for silver halide. These are the hexahedral, tetrahedral, icosahedron and rhombohedral icosahedron crystal forms.

The seven possible crystallographic forms for the cubic crystal lattice structure material are named polyhedra produced by regular crystal structures that are completely surrounded by faces of a single crystallographic form. For example, a regular silver halide grain completely surrounded by a crystallographic plane of cubic morphology is a cube, and a regular silver halide grain surrounded by a crystallographic plane of octahedral morphology is an octahedron. is there.

In addition to regular grains of polyhedral shape produced by being completely surrounded by crystal faces of the same crystallographic form, regular silver halides surrounded by both cubic and octahedral faces. Observing the particles is not unusual. Such a particle is a cubic octahedron (cubo-oct
ohedral). This is shown in Figure 7,
Cubic octahedral grains (9) and (10) are shown here together with cubic grains (1) and octahedral grains (5). Cubic octahedral grains have 14 crystal faces, 6 cubic crystal faces and 8 octahedral crystal faces, and for that reason they are sometimes referred to as tetradecahedral grains. Similar combinations of cubic and / or octahedral crystal faces and orthorhombic dodecahedron crystal faces are possible, with the rare occurrence of grains having cubic, octahedral and orthorhombic dodecahedron crystal faces. Examples are given above in connection with orthorhombic dodecahedron grains, berry (Berr
y) provided by.

[Problems to be solved by the invention]

The object of the present invention is to provide a radiation sensitive emulsion having silver halide grains of increased surface area.
sion).

[Means for solving problems]

The above mentioned object according to the invention comprises a silver halide grain of cubic crystal lattice structure, wherein said silver halide grain is a silver halide crystal lattice from the ground plane of the first crystallographic form. Grain having a ruffled surface by a protrusion that is an extension of, and adjacent to the base surface under the base surface and in the projection exhibits the same silver halide composition, and the projection is Providing a second crystallographic morphology surface,
This can be accomplished with a radiation sensitive emulsion.

This invention relates to silver halide photographic emulsions composed of radiation sensitive grains of cubic crystal lattice structure having a ruffled surface, and photographic elements containing these emulsions.

Being ruffled, these grain faces have a larger surface area than the corresponding flat grain faces. Considering a regular polyhedron surrounded by flat faces in FIG. 18, eg a cube (1) or an octahedron (5) in FIG. 3, each flat face represents a minimum surface area corresponding to the size of the polyhedron. It is clear.

It has been surprisingly discovered that the grain surface area ratio of cubic crystal lattice structured silver halide grains can be significantly increased without significantly altering the overall shape or size of the grains. This is accomplished by simply disturbing (ruffling) the surface provided by the particles. The extent to which the particle surface area ratio is increased is a matter of choice and can vary from a slight increase to more than a two-fold increase in that particle surface area ratio. The grain surfaces used in the practice of the present invention are preferably ruffled to an extent sufficient to increase the grain surface area ratio by 50%. This is more than the accidental increase in grain surface area conventionally achieved by the random non-uniformity of the crystal planes and the unsolicited increase in particle surface area ratio realized by producing composite halogenated grains. Pretty big. The silver halide emulsions of this invention have a grain surface area ratio of at least 100 compared to grains of similar size and shape that do not have a ruffled surface.
Most preferably, it exhibits a ruffled grain surface that increases by%, optimally at least 200%.

The formation of silver halide grains having a ruffled surface begins with any conventional emulsion containing silver halide grains of cubic crystal lattice structure that provide the surface of the crystallographic morphology that silver halide prefers. In silver halide grains that are predominantly silver chloride (more than 50 mol% chloride based on silver) and especially grains in which at least 90 mol% are chloride,
The preferred crystallographic morphology is cubic, and thus the grain faces to be ruffled are cubic (ie, {100}) crystal faces. Other silver halide, silver bromide, silver bromoiodide,
For silver chlorobromide and silver chlorobromide iodide, the preferred crystallographic morphology, and thus the grain faces are cubic or, if formed in the presence of an excess of bromide ion, an octahedron (ie, { 111}).

The preferred crystallographic morphology grain surface for the silver halide used provides a flat surface and serves as a deposition site for additional silver halide to form ruffles (projections). It is therefore clear that the flat surface of the crystallographic morphology favored by the silver halide of the host grain forms the base plane of the ruffle.
The raffle takes the form of protrusions from the base, and these protrusions are extensions of the underlying silver halide cubic crystal lattice structure of the host grain. The silver halide in the raffle adjacent to the ground plane is a composition that favors the same crystallographic morphology as the silver halide of the host grain forming the ground plane.

The silver halide adjacent to the substrate in the protrusion and in the host grain can be the same or different in composition,
The choice of silver halide at each position is limited only by the requirement to form a cubic crystal lattice structure and the requirement that the silver halide at each position favor a common crystallographic morphology corresponding to the crystallographic morphology of the base plane. To be done. Thus, the protrusions adjacent to the base surface are deposited, for example, predominantly on the base surface of silver chloride, as defined above, predominantly silver chloride; on the base surface of silver bromide or silver bromoiodide. Silver bromide; silver bromoiodide deposited on the surface of silver bromide or silver bromoiodide; or optionally deposited on the surface of silver chlorobromide, which also contains iodide It can be formed from a silver halide which is a silver chlorobromide containing compound. Predominantly silver chloride can be deposited on the {100} silver bromide or silver bromoiodide base. However, the protrusions, which are mainly silver chloride, deposited on the base surface of {111} silver bromide or silver bromoiodide have no applicability to the present invention for the reason described below. The portion of the protrusion that does not exist adjacent to the base surface, e.g., the surface of the protrusion, is independent of the silver halide composition of the host grain adjacent to the base surface, and is any known photographically useful silver halide composition. Can have This is because once the protrusions are formed, modification of the surface of the protrusions in any desired manner is a matter of choice.

It was observed that the processes, in most cases, took the form of pyramids and, in some cases, ridges. For convenience of description, the following description is specifically directed to pyramid-shaped projections, but the extension to ridge-shaped projections is obvious. Excluding the accidental rounding phenomenon that can occur at the edges and corners of halogenated grains,
Each protrusion is a pyramid that has a common base with the underlying surface provided by the host particles.

Each pyramid provides a number of surface planes (all but the base) that differ from the crystallographic morphology of the base plane. The number of faces of the surface provided by the pyramid is determined by the crystallographic morphology of the base face and the surface of the pyramid. The combinations are listed in Table I below.

It can be seen from FIG. 18 that each corner of the cube (1) is formed by three {100} crystal faces. The {100} crystal plane pyramid formed on the {111} base plane is similar in shape to a cube corner. This is shown schematically in FIG. This Fig. 8 shows the {111} base plane (1
2) A plan view of a pyramid (11) having three {100} crystal faces (11a), (11b) and (11c) on it.

Similarly, as can be seen in FIG. 3, it can be seen that each corner of the octahedron (5) is formed by four {111} crystal faces. {111} formed on {100} base surface
The crystal plane pyramid resembles an octahedral corner in shape.
This is shown schematically in FIG. Figure 8 shows the {100} base plane (1
4) Four {111} crystal faces (13a), (13b), (13
FIG. 13 is a plan view of a pyramid (13) having c) and (13d).

Regarding the pyramids with orthorhombic dodecahedron faces, as can be seen in FIG. 5, the regular orthorhombic dodecahedron (7) is the intersection of three crystal faces each. And eight corners formed by the intersection of four crystal planes. An orthorhombic dodecahedron, that is, a pyramid providing {110} crystal faces is {10
When located on the 0} plane, it provides four surface planes, thus appearing in a plan view similar to that shown in Figure 9, but when providing the {111} plane, A pyramid with {110} crystal planes provides three surface planes, thus appearing in plan view as shown in FIG.

Formed by {100} crystal faces on {111} base faces 3
It should be pointed out that the two surface plane pyramids and the three surface plane pyramids formed by {110} crystal faces on the {111} base plane appear alike in the plan view, but they can be distinguished. is there. Similarly, {1} on the {100} base plane
A pyramid of four surface planes formed by 11} crystal planes and a pyramid of four surface planes formed by {110} crystal planes on a {100} base plane can be distinguished. Identify the crystallographic morphology of the surface of the pyramid 1
One method is to measure the angle of intersection between the surface plane and the host particle base plane. Another criterion for distinguishing the crystal planes of a pyramid is to note the plane crossing angle of the surface of the pyramid. Comparing these measured crossing angles to the theoretically possible crossing angles and other knowledge about the crystallographic morphology of the host planes provided by the host particles and the number of surface planes provided by the pyramids It allows the positive identification of crystallographic morphology of the plane.

In crystallography, the measurement of the relative angles of adjacent crystal faces is used to identify the crystal faces. Such techniques are described, for example, by Phillips , introductory to crystallography ( An Int
roduction to Crystallography) , 4th edition, John Wiley & Sons. In the above book, Phillips relies on the basic concepts and terminology of crystallography presented here as a basis. These techniques can be combined with the technique of microscopy of silver halide grains to positively identify one or both of the crystal planes of the pyramid and the host grain. Techniques for making electron micrographs of silver halide grains are generally well known in the art and are described, for example, in the following references: B.
M. Spinel and CF Oster,
"Photographic Materials", microscopy
The Encyclopedia o Encyclopedia of Law and Micro Technology
f Microscopy and Microtechniqne ), P. Gray (Gra
y) Ed., Van Nostrand New York, 1973, pages 427-434, in particular the sections used for replica electron microscopy of carbon on pages 429 and 430. A carbon replica of the silver halide grains is first prepared using techniques well known in electron microscopy. A replica of carbon reproduces the shape of the grain while at the same time altering the silver print-out, which is known to result from the use of silver halide grains without a carbon shell. To avoid. Electrons rather than light are used for imaging to allow a greater range of magnifications than when light is used. By tilting the sample to be observed with respect to the electron beam, the selected particles can be compounded such that the line of sight is substantially parallel to both two adjacent crystallographic planes visible as edges. If the grain planes are parallel to the imaging electron beam, the corresponding edges of the grain they define will appear sharper than if the planes simply approached parallel. Once the desired grain orientation is obtained with each two intersecting crystal planes providing edges parallel to the electron beam,
The crossing angle can be measured from electron micrographs of oriented particles. In this way, the relative angle provided by any two intersecting crystallographic planes can be measured. By narrowing the range of possibilities due to visual clues, such as the host crystal shape, the crossing angle for possible crystal forms can be calculated and compared to the measured crossing angle value. In many, if not most, cases, inspection of host particles by electron microscopy allows for positive identification of the basal plane, so that further investigation can be limited to the plane of the pyramid surface.

With reference to the mutually perpendicular x, y and z axes of the cubic crystal lattice, the cubic crystal planes are parallel to two of the axes and intersect the third axis. Thus {100}
The Miller index of is assigned. The octahedral crystal planes intersect each of the three axes at equal intervals, thus being assigned a Miller index of {111}, and the orthorhombic dodecahedron crystal planes are two of three axes. It is well recognized in the art that it intersects the book at regular intervals and is parallel to the third axis, thus being assigned a Miller index of {110}. For a given definition of basic crystal units, one and only one Miller index is assigned to each of the cubic, octahedral and orthorhombic dodecahedron crystal faces.

The crystal faces of the icosahedron, the tetrahedron, the rhombohedral icosahedron and the hexaoctahedra can have different Miller index values, so in Table I they are generally {hhl}, {hhl respectively.
Identified as ko}, {hll} and {hkl} crystal faces. Where h, k and l are each independently a different integer greater than 0, h is greater than l, and k (if present) is less than h and greater than l. Integer h
There is no theoretical limit on the maximum value of, and crystal planes with h-values of 5 or less occur more easily. For convenience, the description that follows relates to surfaces where h is 5 or less. The relationships for faces with h greater than 5 are completely similar.

Considering h-values up to 5, the crystal faces of the tetradecahedra can have any one of the following Miller indices:
{221}, {331}, {441}, {551}, {332}, {55
2}, {443}, {553} or {554}. Figure 10 shows {33
1} Tetrahedron (1
It is an isometric view of 5). Point or point (co
ign) (16) is three intersecting crystal planes (16a), (16b)
And (16c) and is one of eight identical salient angles. The tip or angle (17) has eight intersecting crystal planes (16a), (16c), (17a), (1
7b), (17c), (17d), (17e) and (17f) and is one of six identical salient angles. As is apparent with reference to Table I, there are pyramids with eight surface planes, such as the plane defining the salient angle (17), because the plane of the pyramid surface is the cube provided by the host particles, ie This is a case of an icosahedron on the {100} base plane, that is, a {hhl} crystal plane. On the other hand, if the host particle is an octahedron or {111}
When the surface of the pyramid surface is an icosahedron when it represents the base surface of the
There exists a pyramid with two surface faces. Geometrical relationships are the same for the crystal faces of the tetrahedron with different Miller indices, but the angles at which the surface planes intersect each other and the base plane are different.

The {331} icosahedron crystal planes differ from those offered by all other crystal planes possible for cubic crystal lattice structured silver halides, with a unique arrangement of surface silver and halogen ions. I will provide a. Theoretically estimated,
This unique surface ion configuration is schematically illustrated in Figure 11, where the {331} icosahedron crystal faces are formed by silver ions (2) and bromine ions (3). It is shown. Comparing FIG. 11 with FIGS. 2, 4, and 6 it is clear that the surface positions of silver and bromide ions in each figure are distinguished.
{331} The surface arrangement of silver and bromide ions provided by the tetradecahedron crystal face is orderly, but the cubic, octahedral or orthorhombic dodecahedron silver bromide crystal face is arranged. Richer in variety than what is offered by. This is {33
1} Layering that occurs on the crystal faces of the tetrahedron
Is the result of. Tetrahedron crystal faces with different Miller indices also show layering. Different Miller indices give similar, but nevertheless unique, surface arrangements for silver and halogen ions.

Considering h-values up to 5, tetrahedral crystal faces can have any one of the following Miller indices: {21
0}, {310}, {320}, {410}, {430}, {510},
{520}, {530} or {540}. FIG. 12 is an isometric view of a tetrahedron (18) surrounded by faces of {210} crystallographic morphology. The ridge or ridge (19) is formed by four intersecting crystal planes (19a), (19b), (19c) and (19d) and is one of six identical ridges. The salient angle (20) is six intersections (19a), (19d), (20
a), (20b), (20c) and (20d) and is one of eight identical salient angles. As can be seen with reference to Table I, for example, when the plane of the pyramid surface is a tetrahedron on the basal plane of the cube provided by the host particles, {100}, ie {hk0} crystal faces, for example, the salient angle ( There are pyramids with four-sided faces, such as those defining (19). On the other hand, if the host particles provide octahedral or {111} basal planes, then when the pyramid surface planes are tetrahedral, six surface planes, for example the planes that define the salient angle (20), There is a pyramid with. For tetrahedral crystal planes with different Miller indices, the geometric relationships are the same, but the angles at which the surface planes intersect each other and the base plane are different.

The {210} tetrahedral crystal faces provide a unique arrangement of silver and halogen ions on the surface that differs from the sequence provided by all other crystal faces possible for silver halide in the cubic crystal lattice structure. This theoretically deduced unique surface ion configuration is schematically illustrated in Figure 13, where the {210} tetrahedral crystal faces are formed by silver ions (2) and bromine ions (3). It is shown that FIG. 13 to FIG. 2, FIG. 4, FIG.
As is clear from comparison with FIG. 11, the surface positions of silver and bromide ions in each figure are distinguished. {twenty one
The arrangement of silver and bromine ions on the surface provided by the 0} tetrahedron crystal face is more orderly, but more It is rich in change. This is a result of layer formation that occurs on the {210} tetrahedral crystal faces. Tetrahedra with different Miller indices also show layering. Different Miller indices give similar, but nevertheless unique, surface arrangements for silver and halogen ions.

Considering h-values up to 5, the crystal planes of rhombohedron tetrahedra can have any one of the following Miller indices:
{211}, {311}, {322}, {411}, {433}, {51
1}, {522}, {533} or {544}. Fig. 14 shows {21
1} is an isometric view of a rhombohedral icosahedron (21) surrounded by faces of crystallographic form. The tip or angle (22) is 4
Two crossing crystal planes (22a), (22b), (22c) and (22
d) and is one of six identical salient angles. The salient angle (23) is defined by three intersecting crystal planes (22
a), (23a) and (23b),
And it is one of eight identical salient angles. As is apparent from reference to Table I, when the plane of the pyramid surface is a rhombohedron tetrahedron or {hk0} crystallographic plane on the base plane of the cube or {100} provided by the host particles, , There are pyramids with four surface faces, for example the faces defining the salient angle (22). On the other hand, if the host particle provides an octahedral or {111} basal plane, then when the pyramid surface is a rhombohedral icosahedron, for example, the plane defining the salient angle (23). There is a pyramid with three surface faces. The crystallographic planes of rhombohedron tetrahedra with different Miller indices have the same geometrical relationship, but the angles at which the surface planes intersect each other and the base plane are different.

The crystal planes of the {211} rhombohedra are different from the arrangements provided by all the other crystal planes possible for silver halide in the cubic crystal lattice structure, with a unique arrangement of silver and halogen ions on the surface. I will provide a. Theoretically estimated,
This unique surface ion configuration is shown schematically in FIG. Here, it is shown that the {211} rhombohedral tetrahedral crystal planes are formed by silver ions (2) and bromine ions (3). As is clear from comparing FIG. 15 with FIGS. 2, 4, 6, 11 and 13, the surface positions of silver and bromine ions in each figure are distinct. The arrangement of silver ions and bromine ions on the surface provided by the {211} rhombohedral tetradecahedral crystal plane is orderly,
It is richer in variation than that provided by cubic, octahedral or orthorhombic dodecahedron crystal planes of silver bromide. This is {21
1} This is the result of layer formation that occurs on the crystal planes of the rhombohedral tetrahedron. The rhombohedron tetrahedra with different Miller indices are also
The layer formation is shown. Different Miller indices give similar, but nevertheless unique, surface arrangements for silver and halogen ions.

Considering h-values up to 5, the hexaoctahedral crystal faces can have any one of the following Miller indices: {32
1}, {421}, {431}, {432}, {521}, {531},
{532}, {541}, {542} or {543}. Figure 16 shows
A hexaoctahedral (2 surrounded by faces of {321} crystallographic morphology (2
It is an isometric view of 4). The salient angle (25) has eight intersecting crystal planes (25a), (25b), (25c), (25d), (25e), (2
5f), (25g) and (25h) and is one of six identical salient angles. The salient angle (26) is formed by six intersecting crystal planes (25g), (25h), (26a), (26b), (26c) and (26d), and is one of the six salient angles. The salient angle (27) has four intersecting crystal planes (25a), (25
h), (26a) and (27a).
As can be seen with reference to Table I, the faces of the pyramid surface are cubes provided by host particles, ie {100}
In the case of a hexahedron on the base plane of {circumflex over (i)}, ie, a {hkl} crystal plane, there is a pyramid having eight surface planes, for example the planes defining the salient angle (25). On the other hand
If the host particles represent octahedral or {111} basal planes, then when the pyramid surface planes are hexaoctahedral, a pyramid with six surface planes, such as the plane defining the salient angle (26), Exists. Rarely excluded from the invention due to lack of practical importance, but when the substrate is an orthorhombic dodecahedron or {110} crystallographic form,
The pyramid above it will have a surface area corresponding to the surface forming the salient angle (27). For hexahedral crystal planes of different Miller indices, the geometric relationships are the same, but the angles of the surface planes with each other and with the base plane are different.

The {321} hexaoctahedral crystal faces provide a unique arrangement of surface silver and halogen ions that differs from the sequence provided by all other possible crystal faces for silver halide in the cubic crystal lattice structure. Theoretically estimated,
This unique surface ion configuration is illustrated schematically in Figure 17, where the {321} hexahedral crystal faces are shown to be formed by silver ions (2) and bromide ions (3). ing. FIG. 17 through FIG. 2, FIG. 4, and FIG.
As is clear from a comparison with FIGS. 11, 11 and 15, the positions of the silver and bromide ions on the surface in each figure are distinct. The arrangement of silver and bromine ions on the surface provided by the {321} hexaoctahedral crystal plane is orderly, but more variable than the arrangement provided by the cubic, octahedral or orthorhombic dodecahedron crystal planes. Rich This is a result of the oblique layer formation that occurs on the {321} hexaoctahedral crystal faces. The rhombohedral icosahedron crystal faces with different Miller indices also show oblique layer formation. Different Miller indices are
Similar to silver and halogen ions, but nevertheless gives rise to a unique surface arrangement.

It is interesting to note that it is not the size or number of all specific forms of pyramid that controls the surface area provided by the pyramid, but rather the collective base area it occupies. is there. The reason for this is that the surface area of the surface is in a fixed ratio to the base area for all pyramids of the same morphology. For example, a group of 100 pyramids of a given shape and a small pyramid of the same shape 1
The second population of 000 has the same ratio of collective basal area to collective surface area. That is, if the collective base areas for two populations of pyramids are equal, then their collective surface areas are also equal. Therefore, the degree of ruffledness that can increase the surface area of the host particles is a function of the area covered by the pyramids and the morphology of the pyramids, rather than the size or number of the pyramids. Thus, the present invention is not limited to ruffled particles having any particular size or number of pyramids.

However, making this observation also points out that the surface area ratio (not surface area) provided by the ruffled silver halide grains is directly influenced by the size of the pyramids. Nevertheless, 1000 smaller pyramids of the same morphology and 100 pyramids that provide the same surface area have a much larger collective volume and thus require more silver halide formation. This point favors smaller pyramids over larger ones 1
There are two reasons. Therefore, a pyramid is used that has an average base area that is preferably less than 10 ^-2 times, and most preferably less than 10 ^-3 times the average area of the base surface on which the pyramid is located.

If it is desired to maximize the surface area ratio provided by the pyramids, it is, of course, obvious to choose those pyramids that exhibit the largest surface area ratios themselves, but silver halide contained in relatively small pyramids. The amount of is virtually negligible. A second factor to consider is whether the pyramid basis defines a close-packed polyhedral shape. All of the same shaped pyramids on a given base plane have the same orientation. As can be seen in FIG. 9, the base surface (14) is theoretically completely covered by a pyramid in the form of a pyramid (13), whether the pyramids have the same or different dimensions. You can On the other hand, with the restriction that all pyramids of similar shape on the same base plane must have the same orientation, as is clear from FIG.
The base surface (12) cannot be completely covered by pyramids that are identical in morphology to the pyramids (11), but the space between adjacent pyramids can be reduced when pyramids of different sizes are present.

The existence of raffles formed by crystal planes of pyramids whose crystallographic morphology differs from the base plane provided by host particles is
Confirmed by observation and measurement, as described in the Examples below. The formation of crystal planes with different crystallographic morphology deviates from what would normally be obtained, since the base plane represents a crystallographic morphology suitable for the silver halide deposited thereon. Moreover, the formation of pyramid crystal planes is completely unexpected, and besides this,
Obtaining pyramidal crystal planes of crystallographic morphology, which has heretofore been hardly or never observed for silver halides, is an exceptional departure from the prior art in this field.

Without limiting the invention to any particular theory, possible mechanisms for the formation of crystal planes are described. Considering an emulsion containing host grains surrounded by a plane of preferred crystallographic morphology for the silver halide adjacent to the grain surface, the deposition of additional silver halide favoring the same crystallographic morphology gives Substantially uniform shelling occurs, and the resulting shelled grain is large in size but still exhibits the same crystallographic morphology of the crystal grains as the host grain.

Referring back to FIG. 7, it is possible to change the shape of octahedral crystal faces to cubic crystal faces and vice versa by changing the precipitation conditions during grain growth during emulsion precipitation. It is known to be. Thus, octahedral grains (5) surrounded by {111} crystal faces
Form a cube (1) by continuously changing the tetradecahedron (9), the tetradecahedron (10), and simply the precipitation conditions to be suitable for the formation of {100} crystal faces. Can be grown as you would. (In practice, cubes and tetradecahedrons are somewhat larger than usually shown for octahedra.) Comparing tetradecahedrons (9) and (10), silver halide was found to remain on the octahedral crystal face residue. It will be easy to see that the cubic crystal faces grow because of the more rapid deposition. As can be seen from this, the predominant crystallographic plane of the silver halide grains is of the crystallographic form on which silver and halogen ions precipitate most slowly. Once only the faces of this less reactive crystallographic morphology, in this case, stay above the {100} face of the cubic grain (1), silver and halogen ions are isotropically deposited on these surfaces. To do.

Sequential formation of crystallographic planes of different crystallographic morphology than that of the deposited silver halide slows the deposition rate of silver and halogen ions on the desired crystallographic morphology planes. Depends on fixing.
Many examples of growing host particles that provide cubic or octahedral faces to form grains in which some or all of the faces are other crystallographic forms, i.e. octahedral or cubic, are
It can be found in this area. Orthorhombic dodecahedron silver halide grains are rare, but similar growth transformations in grain shape are equally applicable to this crystallographic morphology. By observing the sample taken in the middle stage of grain growth, it was confirmed and possible that a pattern of growth similar to the conversion of octahedral grains to cubic grains described above with reference to FIG. It was

Surprisingly, however, there are other possible growth patterns and it is this latter pattern of growth that gave rise to the present invention. Referring to FIG. 7, when the octahedral particles (5) are grown to form the cubic particles (1), the {100} crystal faces occur at the salient angles of the octahedron, and until the cubic morphology is completed. It can be seen that the area increases progressively. As is readily apparent by comparing FIG. 7 with FIGS. 8 and 9, the formation of the pyramid surface does not occur selectively at the salient angle of the host particle or even at the edge, but on the surface of the particle.

This forms a condition that causes the deposition rate of silver and halogen ions for at least one other crystallographic form to be slower than the deposition rate of silver and halogen ions for the crystallographic form represented by the host particle. It is thought to be made possible by. The deposition of silver halide on the crystal planes of host grains under these formed conditions causes pyramids to be formed over the planes of the host grains, surrounded by surface planes of slow growing crystallographic morphology. . Maximum ruffling is achieved when substantially all of the surface of the host particle is just coated with pyramidal protrusions. As deposition continues thereafter, the particles eventually return to their non-ruffled morphology, but are surrounded by crystallographic morphology planes corresponding to those of the intermediate pyramid surface.

Throughout the decades of crystallographic studies of silver halide, in this field, there have been ruffled grain faces of the icosahedron, tetrahedron, rhombohedral icosahedron or hexaoctahedral crystallographic form or any No grain faces were also observed, and rarely grain faces of the orthorhombic dodecahedron crystallographic morphology were commonly observed {100} and {11}.
1} It suggests that the range of conditions suitable for ruffled grain surface is not wide. It has been discovered that growth modifiers can be used to produce ruffled grain surfaces. The identified growth modifiers are organic compounds. It is believed that the growth modifiers are effective because they exhibit adsorption preferences for the crystal planes of the pyramids formed due to their unique arrangement of silver and halogen ions. Thereby, the growth modifier slows the deposition rate of halogen ions and silver ions on the pyramid crystal plane with respect to the deposition rate of silver ions and halogen ions on the crystal planes of the original host particles. Thus, the crystallographic planes of the crystallographic morphology provided by the planes of the pyramid surface are persistent and dominate.
On the other hand, the different crystal planes originally provided by the host grains are rapidly diminished or eliminated by further deposition of silver halide. Growth modifiers that have been experimentally proven to be effective in producing ruffled grain surfaces and combinations of pyramid crystal faces and host particles produced by these growth modifiers are described in the Examples below.

These modifiers are effective under the conditions of use in the examples. Experimentally screening various growth modifier candidates by changing the precipitation conditions of silver halide,
In order to achieve a ruffled particle surface, a number of parameters need to be satisfied, including not only the proper selection of growth modifiers, but also the proper selection of other precipitation parameters identified in the examples. That is the conclusion. For silver halide precipitation, it is possible to achieve a ruffled grain surface with compounds that have been shown to be effective as growth modifiers to produce a ruffled grain surface if the attendant conditions are modified. It was observed that nothing could be done. However, when demonstrating the successful preparation of silver halide emulsions containing grains with ruffled grain faces, routine experimental studies of systematically varying parameters lead to additional useful formulation techniques. It is understood that it is easy.

Once the silver halide grain growth conditions that selectively retard the deposition of silver halide on the pyramid crystal planes are satisfied, continuous grain growth usually results in grains present in the silver halide precipitation reactor. All the raffling of happens. However, this does not mean that all of the radiation-sensitive silver halide grains in the emulsion of the present invention need to have a ruffled surface. For example, silver halide grains having a ruffled surface can be blended with any other conventional silver halide grain population to produce the final emulsion. Although silver halide emulsions containing all identifiable ruffled grain surfaces are considered to be within the scope of the present invention, in most applications grains having at least one identifiable ruffled surface will be the entire grain population. Present in a proportion of at least 10% of the total, and usually these particles will be greater than 50% of the total particle population.

Emulsions of host grains that provide cubic and / or octahedral crystal faces used in the preparation of the emulsions of the invention, and any emulsions lacking the ruffled faces that are incorporated into the emulsions of the ruffled grains according to the invention can be various. Can be selected from among ordinary emulsions. Generally, research closures
ー ( Reserch Disclosure ), Vol.176, December 1978 issue,
Techniques for producing surface latent image forming particles, internal latent image forming particles, internal fogged particles, surface fogged particles, and blends of different particles, as described in item 17643, Section I, are provided for the preparation of emulsions according to the present invention. Applicable to

It is particularly conceivable to use thin and high aspect ratio tabular grain silver halide emulsions as host grain emulsions. Such emulsions are described in the following references: Wilgus et al., U.S. Pat. No. 4,434,262; Kofron et al., U.S. Pat. No. 4,439,520; Daubendiek et al., U.S. Pat. No. 4,414,310; Abbott. (Abbott) et al U.S. Pat. Nos. 4,425,425 and
4,425,426; Wey US Pat. No. 4,399,215
U.S. Pat. No. 4,433,048 to Solberg et al.
Issue; Dickerson US Patent 4,414,304
Mignot, US Pat. No. 4,386,156;
Migunotto (Mignot), Research Disclosure (Research Disclosure), Vol.232, 8 May 1983, item 23210; John's (Jones) et al., US Patent No. 4,478,929
Evans et al. U.S. Pat. No. 3,761,276; Maskasky U.S. Pat. No. 4,400,463; Wey et al. U.S. Pat. No. 4,414,306; and Maskasky U.S. Pat. No. 4,435,501. And
For details, refer to the above-mentioned document.

As defined herein, a high aspect ratio tabular grain emulsion is composed of a dispersion medium and silver halide grains wherein at least 50% of the total projected area of the silver halide grains is 0.3 mm thick. less than μm and diameter of at least 0.6
provided by tabular silver halide grains having a mean aspect ratio of greater than 8 μm and 8: 1. In some applications, such as those that record radiation within a portion of the spectrum that can be absorbed by silver halide, at least 50% of the total projected area of the silver halide grains has a thickness of less than 0.5 μm, a diameter of at least 0.6 μm, and Provided by tabular silver halide grains having an average aspect ratio greater than 8: 1. Preferred high aspect ratio tabular grain emulsions are those having an average aspect ratio of at least 12: 1 and optimally at least 20: 1. In addition,
It is preferred to increase from 50% to 70%, optimally 90%. Emulsions of silver bromoiodide are generally preferred for camera speed imaging applications, while silver bromide and silver bromoiodide emulsions are preferred for radiographic imaging.

As defined herein, a thin tabular grain emulsion is composed of a dispersion medium and silver halide grains, wherein at least 50% of the total projected area of the silver halide grains is 0.
It is provided by tabular silver halide grains having an average aspect ratio of less than 2 μm and greater than 5: 1. The preferred conditions described above for high aspect ratio emulsions also apply to thin tabular grains. Emulsions satisfying both definitions are preferred for most photographic applications.

In addition to the novel grain structures identified above, the radiation-sensitive silver halide emulsions of the present invention and photographic elements incorporating them can take any convenient conventional form. Emulsions are based on the Research Disclosure ( Re
search Disclosure ), item 17643, Section II.

The radiation-sensitive silver halide grains of the emulsion are capable of chemically sensitizing the surface. Precious metals (eg gold), medium chalcogens (eg sulfur, selenium, or tellurium),
It is especially envisaged to use the reduction sensitizers individually or in combination. Typical chemical sensitizers are
Research Disclosure ( Research
Disclosure ), item 17643, Section III.

Silver halide emulsions can be spectrally sensitized with various classes of dyes, including the polymethine dye class. Such dyes include cyanines, merocyanines, complex cyanines and merocyanines (i.e., tree, tetra, and poly-nuclear cyanines and merocyanines), oxonols, hemioxonols, styryls, merostyryl. And streptocyanins. Spectral sensitizing dyes are described in Research de cited above
Office closures (Research Disclosure), item 1764
Illustrated in Section IV.

The silver halide emulsions of the present invention, as well as other layers of the photographic element, comprise hydrophilic colloids as vehicles, alone or in combination with other polymeric materials (eg, latex),
Can be included. Suitable hydrophilic materials include: naturally occurring substances such as proteins, protein derivatives, cellulose derivatives such as cellulose esters, gelatin, such as alkali-treated gelatin (cattle, bone, or hide). Gelatin) or acid-treated gelatin (pig skin gelatin), gelatin derivatives such as acetylated gelatin, phthalated gelatin, and polysaccharides such as dextran, gum arabic, zein, casein, pectin, collagen derivatives, collodion. , Agar, arrowroot and albumin. These vehicles can be cured by conventional methods.
Vehicles and curing agent, research di cited above
Closure ( Research Disclosure ), Item 1764
3, detailed in Sections IX and X.

The silver halide photographic elements of this invention can contain other addenda conventional in the photographic art. Useful additives are, for example, Research disk Rosi cited above
Turbocharger chromatography (Research Disclosure), are described in the item 17643. Other common useful additives include: antifoggants and stabilizers, couplers (eg, dye forming couplers, masking couplers and DIR couplers), DIR compounds, antifouling agents, images Dye stabilizers, absorbing substances such as filter dyes and UV absorbers, light scattering substances, antistatic agents, coating aids, plasticizers and lubricants.

The photographic elements of this invention can be simple black and white or monochrome elements consisting of a support bearing a silver halide emulsion layer, or they can be multilayer and / or multicolor elements. Photographic elements produce images in the low to very high contrast range, for example, halftone images in graphic arts. The photographic elements can be designed to be processed in separate solutions or in a camera. In the latter case, the photographic element is a conventional image transfer feature, such as Research Disclosure , cited above, item
17643, those exemplified in Section XXIII. Multicolor elements contain dye image-forming units sensitive to each of the three primary regions of the spectrum. Each unit can consist of a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. In another format, one or more emulsions, one
Alternatively, two or more segmented layers can be arranged by use of microvessels or microcells, as described, for example, in Whitmore, US Pat. No. 4,387,154.

Preferred multicolor photographic elements according to the invention containing incorporated dye image-providing material have at least one green-sensitive silver halide emulsion layer having a yellow dye-forming coupler associated therewith, a magenta dye-forming coupler associated therewith. Having at least one green-sensitive silver halide emulsion layer, and at least one red-sensitive silver halide emulsion layer having a cyan dye-forming coupler associated therewith, and at least one containing grains having a ruffled surface as described above. It comprises a support carrying a silver halide emulsion layer.

The element of the invention comprises an additional layer that is conventional in photographic elements,
For example, it may contain a topcoat layer, a spacer layer, a filter layer, an antihalation layer and a scavenger layer. The support can be any suitable support used with photographic elements. Typical supports include polymeric films, papers (including polymer coated papers), glass and metal supports. For more information on supports and other layers of the photographic elements of the present invention, Research Disclosure cited above (Research Disc
losure ), item 17643, section XVII.

Photographic elements can be imagewise exposed with various forms of energy. Such energies include incoherent (such as those produced by the ultraviolet, visible and infrared regions of the electromagnetic spectrum and electron and beta radiation, gamma rays, x-rays, alpha particles, neutron rays, and lasers ( Irregular phase) form or coherence (phase)
Particulates in the form of and other forms of wave-like radiant energy. If you want to expose a photographic element with X-rays,
Photographic element features as found in ordinary radiation element, for example, Research Disclosure (Research
Disclosure ), Vol. 184, August 1979, item 18431.

Processing of the image-wise exposed photographic element can be carried out in any convenient conventional manner. Procedure, developer and developer modifiers Research disc rows cited above
Jar ( Research Disclosure ), section XIX, XX respectively
And XXI.

The emulsions of this invention can be substituted with conventional emulsions to satisfy known photographic uses. Moreover, the emulsions of the invention can lead to further photographic advantages. In general, further photographic advantages are: (a) an increased surface area ratio enabled by the ruffled particles, (b) various crystal faces provided by the ruffled particles, and (c) ruffled particle faces and adsorption. Can be attributed to one or a combination of high affinity with the compound.

For example, the present invention can provide increased photographic sensitivity. Imagewise exposure of an emulsion to light in the minus blue portion of the spectrum (ie, the green and / or red portion of the spectrum), thus limiting the maximum minus blue sensitivity that can be achieved in photographic applications that require spectral sensitization. Is
It is generally accepted in the art that it is the amount of spectral sensitizing dye that can be adsorbed on the surface of particles of a selected size. It should be noted that decreasing the average grain size to increase the grain surface area ratio, and thus the amount of sensitizing dye per unit volume of silver halide, is ineffective in increasing sensitivity. This rather reduces the photographic speed. The present invention allows the realization of increased photographic speed by increasing the surface area ratio of the particles without reducing the average particle size.

When considering the increase in minus blue sensitivity, the angle at which light impinges on the spectral sensitizing dye adsorbed on the crystal plane of the grain is one important issue to consider. Dipole [Zubinden the transition moment of the spectral sensitizing dye adsorbed to the crystal surface of the silver halide grains provided (Zbinden), infrastructure Red
Spectroscopy of High Polymer (Infrared
Spectroscopy of High Polymer) , Academic Press, New York, 1964, pp. 215] is the most efficient at capturing photons when they are substantially perpendicular to the direction of the exposing radiation. The grains are predominantly in the emulsion, as is typical in emulsions containing predominantly non-tabular grains (eg, regular cubic or octahedral grains) or low aspect ratio (eg, less than 5: 1) tabular grains. In the case of random orientation at, the grain surface ruffling does not change the mean angle of incidence of exposing radiation with the dipole of the transition moment of the adsorbed spectral sensitizing dye. In this case, the achievable increase in sensitivity is approximately proportional to the increase in surface area ratio.

In conventional thin and high aspect ratio tabular grain emulsions, the grains are typically oriented with their major faces normal to the direction of the non-scattering exposing radiation. For most spectral sensitizing dyes, the transition moment dipole is parallel to the crystal plane in which it is absorbed, and therefore
The perpendicular orientation of the silver halide crystal planes with respect to the direction of the exposing radiation is also perpendicular to the dipole of the transition moment of the spectral sensitizing dye. Thus, the faces of the particles are already optimally oriented for non-scattered dye absorption. In this case, the increase in grain surface area due to raffling increases the amount of spectral sensitizing dye that can be adsorbed to the grain surface before desensitization occurs, but this increase in grain surface area results in an increase in sensitivity. , The transition moment of the adsorbed spectral sensitizing dye is reduced by the less efficient orientation of the dipole.
However, if the exposing radiation scatters significantly before reaching the spectrally enhanced and ruffled thin or high aspect ratio tabular grain emulsion layers, the dipole angularity of the transition moment of the dye The orientation is reduced, if not significantly lost. Thus, the optimum location for the emulsion of spectrally sensitized and ruffled thin or high aspect ratio tabular grains in a photographic element is below the light-scattering layer that is closer to and above the support. .
For example, in multicolor photographic elements such emulsions are also most efficient as slow green and / or red recording layers usually located closest to the photographic support.

If desired, the photographic speed of these recording layers can be increased by using reflective materials in one or more emulsion layers or in the underlayer. Reflective materials in the silver halide emulsion layers include high refractive index pigments [Marriage UK Patent No. 504,283 and Yuji (Y.
utjy) et al., British Patent No. 760,775], or a reflective subbing layer containing silver halide [Russel US Pat. No. 3,140,179].

While the above description was specifically directed to the use of minus blue absorbing spectral sensitizing dyes, a similar idea was applied to adsorbed spectral sensitizers, regardless of the spectral region they absorb. I understand that this is the case. The combination of a blue absorbing spectral sensitizing dye with an emulsion having randomly oriented and ruffled grains of a silver halide composition capable of absorbing blue light (eg, silver bromide and silver bromoiodide) comprises: It is specifically recognized as being one of the photographically advantageous forms of the invention.

In the above description, only an increase in the surface area ratio of the particles is needed to explain the advantages of photography. However,
The photographic advantages can also be attributed to the improved interaction between the adsorbed additive and the ruffled halogenated grain surface. For example, when the growth modifier is present adsorbed on the ruffled surface of the particle and has the known photographic utility of being augmented by adsorption to the particle surface, due to its closer association with the particle surface, Alternatively, improved photographic performance can be expected due to the reduced mobility of the growth modifiers. The reason for this is that the growth modifiers, in order to produce the crystallographic planes of the pyramids, are larger in their crystallographic morphology than those shown for any of the other possible silver halide crystallographic morphologies. This is because it is necessary to show priority.

This can be understood, for example, by considering the growth of silver halide grains having both cubic and hexahedral crystal faces in the presence of an adsorbed growth modifier. If the growth modifier shows an adsorption preference for the hexaoctahedral crystal faces over the cubic crystal faces, the deposition of silver and halogen ions on the hexaoctahedral crystal faces is more likely than along the cubic crystal faces. It is retarded to a large extent, and grain growth selects hexaoctahedral crystal faces to eliminate cubic crystal faces. As is apparent from the above, growth modifiers that generate hexaoctahedral crystal faces adsorb more closely to these grain surfaces during grain growth than to other halogenated grain surfaces, and to this increase in The adsorption is transferred to the finished emulsion.

Providing typical photographic uses, Locker
U.S. Pat.No. 3,989,527 discloses a radiation-sensitive silver halide grain having a spectral sensitizing dye adsorbed on the grain surface,
Emulsion containing no spectral sensitizing dye and containing a combination of silver halide grains having an average diameter selected to maximize light scattering, typically in the range 0.15 to 0.8 μm. To improve the sensitivity of the photographic element. Upon imagewise exposure, the radiation impinging on the particles containing no dye is scattered rather than absorbed. As a result, the amount of exposing radiation impinging on the radiation-sensitive imaging particles having the spectral sensitizing dye adsorbed on the surface is increased.

This approach faced one drawback. To some extent, the initially dye-free grains adsorb the spectrally sensitized dye that has migrated from the initially spectrally sensitized grains because the spectrally sensitized dye can migrate through the emulsion. To the extent that the initially spectrally sensitized grains were optimally sensitized, migration of dye away from their grain surface reduces sensitization. At the same time, adsorption of the dye on the particles intended to scatter the imaging radiation reduces the scattering efficiency.

It should be noted that in the examples below, spectral sensitizing dyes were identified as effective growth modifiers for the formation of ruffled silver halide grains. A radiation-sensitive silver halide grain having a ruffled surface and a spectral sensitizing dye of a growth modifier adsorbed on the ruffled surface were treated with a Locker (Locke
When used in place of the spectrally sensitized silver halide grains used in r), the adverse transfer of dye from the ruffled grain surface to the silver halide grains intended for light scattering is reduced or eliminated. In this way, the photographic efficiency can be improved.

Illustrating other advantageous photographic applications, the layer structure of multicolor photographic elements incorporating dye image-providing materials, such as couplers, during processing can be simplified. Emulsions intended for recording green exposure can be prepared using a growth modifier which is a green spectral sensitizing dye, while emulsions intended for recording red exposure are those which are red spectral sensitizing dyes. It can be prepared using a denaturant. Instead of coating the green and red emulsions in separate color forming layer units, as is commonly practiced because the growth modifier is tightly adsorbed to the grains and does not migrate, the two emulsions are blended, and It can be applied as a single color-forming layer unit. The blue recording layer can take any conventional form, and a conventional yellow filter layer can be used to protect the compounded green and red recording emulsions from exposure to blue light. The structure and processing of the photographic element is unchanged except that the green and red recording emulsions are blended in a single layer in a single color forming layer unit or in groups of layers of differing sensitivity. When using a chloride recording emulsion, the approach described above can be extended to incorporate blue, green and red recording emulsions in a single color forming layer unit and the yellow filter layer can be eliminated. The advantage in both cases is the reduction in the number of emulsion layers required compared to the corresponding conventional multicolor photographic elements.

In a more general application, the substitution of emulsions according to the invention containing a growth sensitizing spectral sensitizing dye results in more spectral properties unchanged than the corresponding emulsions containing silver halide grains lacking the ruffled surface. Will produce an emulsion. When the growth modifier can suppress fog, for example, it was shown in the Examples to be an effective growth modifier 2.
In the case of mercaptoimidazoles or any of the tetraazaindenes, more effective fog suppression can be expected at lower concentrations.

Various photographic effects, such as photographic speed, minimum background density level, latent image stability, nucleation, developability, image tone, absorption, and reflectivity are affected by particle surface interactions with other components. Is recognized to receive. Ingredients such as peptizer, silver halide solvent, sensitizer or desensitizer, supersensitizer, halogen acceptor, dye, antifoggant, stabilizer, latent image retainer, nucleating agent, tone modifier Agents, development accelerators or inhibitors (inhifito
r), development restrainers, developers, and other additives that uniquely match the faces of the ruffled grain have exceeded those achievable with silver halide grains of different crystal faces. , Significant advantages in photographic performance can be obtained.

〔Example〕

The invention is explained in more detail by the following specific examples. In each of the examples, all solutions are aqueous solutions unless otherwise noted. Dilute nitric acid or dilute sodium hydroxide was used to adjust pH as needed.

Example 1 Emulsion Example 1 is a compound (I) known to be useful as an antifoggant and stabilizer, 5-carboethoxy-4-hydroxy-1,3,3a, 7-tetraaza. The preparation of a ruffled plate-shaped grain silver bromoiodide emulsion using indene as a growth modifier is exemplified.

To a reactor equipped with a stirrer was added 0.05 mol of a thin yet high aspect ratio tabular grain silver bromoiodide emulsion (6 mol% I). This emulsion contains about 40 g / Ag mol of gelatin,
Hereinafter referred to as host grain emulsion (1). The tabular grains had an average grain size of 5.3μ and a thickness of 0.07μm. Water was added to bring the total weight to 50 g. This emulsion at 40 ° C,
Compound (1) 6.0 mmol / initial Ag mol dissolved in 1 ml methanol, 1 ml water and 3 drops triethylamine were added. The emulsion was then held at 40 ° C for 15 minutes. pH 40
Adjusted to 6.0 at ° C. Raise the temperature to 60 ° C, and p
Ag was adjusted to 8.5 with KBr at 60 ° C. and kept at that value during precipitation. A 2.0 molar solution of AgNO ₃ was introduced at a constant rate over a 38 minute period, during which a solution with a KBr of 1.88 moles and a KI of 0.12 moles was added as needed.
The pAg was kept constant. A total of 0.015 mol Ag was added.

An electron micrograph of a carbon replica of the obtained emulsion grains is shown in FIG. The raffles were small, closely located, and evenly distributed over the faces of the tabular grains.

Example 2 Emulsion Example 2 uses a compound (II), which is known to be useful as a blue spectral sensitizing dye, as a growth modifier to prepare ruffled tabular grains of silver bromoiodide. The preparation of the emulsion will be exemplified.

Emulsion Example 2 was prepared as described in Example 1 except that the growth modifier was Compound (II) 6.0 dissolved in 3 ml methanol, 2 ml water and 2 drops triethylamine.
It was mmol / Ag mol. Precipitation is carried out for 37.0 minutes and Ag
0.015 mol was consumed.

An electron micrograph of the obtained emulsion is shown in FIG. Using the above preparation conditions, but instead of the tabular grain host emulsion
Using a regular octahedral grain emulsion of AgBr, compound (II) was determined to be a growth modifier that produces crystal planes of pyramids in the form of {211} rhombohedral tetrahedra. . The ruffle was similar to that of Example 1.

Example 3 Emulsion Example 3 is a compound (III) anhydro-5- which is known to be useful as a green spectral sensitizing dye.
Chloro-9-ethyl-5'-phenyl-3,3'-di-
Illustrates the preparation of a pure bromide emulsion of ruffled tabular grains using (3-sulfopropyl) oxacarbocyanine hydroxide, a triethylamine salt as a growth modifier.

To a reactor equipped with a stirrer was added 0.05 mol of AgBr emulsion of thin and high aspect ratio tabular grains containing about 20 g / Ag mol of gelatin with an average particle size of 5.6 μm and a thickness of 0.10 μm. Hereinafter, this emulsion is referred to as host grain emulsion (2). Water was added to bring the total weight to 50 g. 40 in this emulsion
Compound (III) dissolved in 2 ml of methanol at ℃ 5.
0 mmol / initial Ag mol was added. Then add this emulsion to 4
Hold at 0 ° C for 15 minutes. The pH was adjusted to 6.0 at 40 ° C. Reduce the temperature to 30 ° C and adjust the pAg to 7.6 with KBr at 30 ° C,
And maintained at that level during precipitation. AgNO ₃ solution 2.0
The moles are added at a constant rate for 10 minutes, during which the KBr
A 2.0 molar solution was added as needed to keep the pAg constant. A total of 0.020 mol Ag was added.

An electron micrograph of the grains of the emulsion thus obtained is shown in FIG. The raffles are larger, more closely spaced than in the previous example, and are evenly distributed across the plane of the plate-like grains. Using similar conditions, but using regular octahedral host particles of AgBr, compound (III) yields {10
0} was determined to be a growth modifier.

Example 4 The four parts of Example 4 show the effect of varying pAg and precipitation temperature on the properties of the ruffles produced. The host is a tabular grain AgBr emulsion and the growth modifier is compound (IV) anhydro-9-ethyl-5,5'-diphenyl-3, which is known to be useful as a green spectral sensitizing dye. It was 3'-di (3-sulfobutyl) oxacarbocyanine hydroxide, a monosodium salt.

To a reactor equipped with a stirrer was added 0.05 mol of host particle emulsion (2). Water was added to bring the total weight to 50 g. Compound (IV) 5.0 dissolved in 9 ml of methanol at 40 ° C in this emulsion
Mmol / initial Ag mol was added. Then add this emulsion to 40
Hold at 15 ° C for 15 minutes. The pH was adjusted to 6.0 at 40 ° C. Table II
2.0 mol AgNO ₃ solution 0.0 under pAg and temperature conditions shown in
2 moles were introduced at a constant rate for a period of 10 minutes, during which a 2.0 molar solution of KBr was added as needed to keep the pAg constant.

Figures 21A, 21B, 21C and 21D show electron micrographs of the particles obtained. Example 4A produced large flat triangular growths. Example 4B produced growth of some flat triangles and some smaller pyramids in 4A. Example 4C produced a fairly uniform pyramid. Example 4D was uniform and closely spaced.
Created a small pyramid. When examined, the growth was {10
It was shown to have a 0} (cubic) crystal plane. Compound (IV) is pAg 7.6, in the presence of this compound at 40 ℃,
It was determined to be a {100} growth modifier by depositing AgBr on a regular octahedral grained host emulsion. A cube of AgBr formed.

Example 5 Emulsion Example 5 is a compound (V) 5- (3-ethyl-) known to be useful as a blue spectral sensitizing dye.
Illustrates the preparation of a ruffled tabular grain silver bromide emulsion using 2-benzothiazolinylidene) -3- (3-β-sulfoethyl-rhodamine as a growth modifier.

To a reactor equipped with a stirrer was added 0.04 mol of host particle emulsion (2). Water was added to bring the total weight to 40 g. To this emulsion at 40 DEG C. was added 7 ml of N, N-dimethylformamide, 3 ml of water and 4 mmol of compound (V) dissolved in 2 drops of triethylamine / initial mol of Ag. This emulsion is then placed at 40 ° C.
Hold for 15 minutes. The pH was adjusted to 6.0 at 40 ° C. Temperature 6
Raised to 0 ° C and adjusted pAg to 8.5 with KBr at 60 ° C and maintained that value during precipitation. A 2.0 molar solution of AgNO ₃ was introduced at a constant rate over a period of 20 minutes, during which a 2 molar solution of KBr was added as needed to keep the pAg constant. A total of 0.02 mol Ag was added.

An electron micrograph of the resulting emulsion grains is shown in FIG. The faces of the particles were evenly covered with closely spaced, sharp, small pyramid raffles. This was expected from the study of the same growth modifier using non-platy host grain emulsion,
It coincided with the crystal plane of the {211} rhombohedral tetrahedron.

Example 6 Example 6 illustrates the preparation of ruffled tabular grain silver bromoiodide emulsion using compound (V) (Example 5) as a growth modifier. Example 6A is a control and shows that no ruffles form when the growth modifier is added after, but not before, the precipitation of silver halide on the host emulsion. The host emulsion (0.05 moles for each experiment) and precipitation conditions are as in Example 1.
As described in Example 1 except that the growth modifier was compound (V) and the addition rate of the AgNO ₃ solution was half that used in Example 1 (precipitation time about 74 minutes,
0.015 mol Ag was added). The results of three experiments are shown in Table III.
Shown in

Figures 23A, 23B and 23C show electron micrographs of the resulting particles. In Example 6A, the addition of a growth modifier after precipitation resulted in no growth of ruffles on the host emulsion particles. Example 6B with the same amount of growth modifier added prior to precipitation
Produced uniform, closely-spaced small raffles. Example 6C, which added high levels of growth modifier, produced similar results but had a slightly better defined ruffle (pyramid).

The interfacial angle of the ruffle on the electron micrograph of Example 6C was measured to determine the crystallographic morphology. It was found that the angle between the vectors of the faces was 35 °. The theoretical angle between {211} vectors is 33.6 °. Therefore, this form is {21
1} It was a rhombohedral twenty-four-sided body. This is in agreement with other observations of {211} rhombohedral tetrahedra formed from non-platy host particles and formed with compound (V) as a growth modifier.

Example 7 In Example 7, again, the compound (V) was used as a growth modifier.
The preparation of a ruffled tabular grain silver bromoiodide emulsion using (Example 5) is illustrated, showing that the results are dependent on the level of growth modifier added.

The host emulsion (0.05 mol for each experiment) and precipitation conditions were as described in Example 6. Experimental details are shown in Table IV.
Shown in

Figures 24A, 24B, 24C and 24D are electron micrographs of the resulting emulsion grains. Example 7A with no growth modifier and Example 7B with 0.75 mmol / Ag mol growth modifier showed no ruffles. At 1.5 mmol, a relatively large frustoconical pyramid appeared, as shown in Figure 24C. At 3.0 mmol, Example 7D produced uniform, tightly-distributed small ruffles. The crystal planes of the pyramids were consistent with the {211} crystal planes expected from using compound (V) as a growth modifier in the previous example.

Example 8 Emulsion Example 8 is a compound (XIII) anhydro-3,9-diethyl-5,5 ', 6'-trimethoxy-3'-(3-sulfopropyl) thia which is a red spectral sensitizing dye. The preparation of an emulsion of ruffled tabular grain silver bromide using carbocyanine hydroxide as a growth modifier is illustrated.

To a reactor equipped with a stirrer was added 0.05 mol of host particle emulsion (2). Water was added to bring the total volume to 50 ml. To this emulsion at 40 DEG C. was added 5 mmol of compound (XIII) / initial Ag mol dissolved in 3 ml of N, N-dimethylformamide. pH
Adjusted to 6.0 at 40 ° C. The pAg was adjusted to 7.6 at 40 ° C and maintained at that value during precipitation. A 2.0 molar solution of AgNO ₃ was introduced at a constant rate over a period of 10 minutes, during which KBr
A 2.0 molar solution was added as needed to keep the pAg constant. A total of 0.02 mol Ag was added.

FIG. 25 is a micrograph of the obtained emulsion grains. The closely arranged ruffles are evenly distributed over the plane of the plate-like particles.

Example 9 The emulsion of Example 9 illustrates the preparation of ruffled silver bromide tabular grains by physical ripening in the presence of a fine grain silver bromide emulsion and a growth modifier.

Example 9A Average particle size in a reactor equipped with a stirrer containing 167 g of gelatin / Ag mol of gelatin and having a weight of 65 g
Newly prepared fine grain silver bromide emulsion 0.02 μm 0.015
Mole was added. To this emulsion, at 40 ° C., compound (VII) 4-hydroxy-6-methyl-1,2,3a, 7-tetra-, a known antifoggant and stabilizer, dissolved in 2.5 ml of water and 2 drops of triethylamine. Azaindene 0.18 mmol (6
Mmol / Ag mol of host emulsion) was added. Then an amount of 0.03 mol of host grain emulsion (2), made up to 25 g, was added. The pH was adjusted to 6.0 at 40 ° C and the pAg was adjusted to 9.3 at 40 ° C. The mixture was then heated to 60 ° C. for 4 hours.

FIG. 26A is an electron micrograph showing the resulting fairly uniform, closely spaced raffle. The raffles consisted of crystallographic planes of pyramids of {110} (orthorhombic dodecahedron) crystallographic morphology.

Example 9B An emulsion Example 9B was prepared as described in Example 9A, but was dissolved in 2 ml of water and 2 drops of triethylamine, compound (VIII) 4-, a known antifoggant and stabilizer. Hydroxy-6-methyl-2-methylthio-1,3,3a, 7-tetraazaindene was used as a growth modifier.

FIG. 26B is an electron micrograph showing the resulting relatively large and closely spaced raffle. The raffles were composed of crystal planes of pyramids in the crystallographic form of {211} rhombohedral tetrahedra.

Example 9C An emulsion Example 9C was prepared as described in Example 9A, except that compound (V) dissolved in 6 ml N, N-dimethylformamide, 2 ml water and 2 drops triethylamine was used as a growth modifier. used.

FIG. 26C is an electron micrograph showing the resulting uniformly closely spaced raffle. The crystal planes of the pyramids were compound (V) as a growth modifier in the previous example.
Was used to match the expected {211} crystal face.

Example 9D An emulsion Example 9D was prepared as described in Example 9A, but with compound (IX) 5-imino-3-thiourazole as the growth modifier dissolved in 2 ml of N, N-dimethylformamide. used.

FIG. 26D is an electron micrograph showing the resulting uniform, closely spaced raffle. Raffle is {110}
It consisted of crystal planes of pyramids of the (orthorhombic dodecahedron) crystallographic form.

Example 9E 0.0667 mol of host particle emulsion (2) was added to a reactor equipped with a stirrer. This was mixed with 0.033 mol of a 0.05 μm silver bromide emulsion. This emulsion contains 56 g / Ag mol of gelatin and is a known antifoggant and stabilizer, compound (X) 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene, sodium salt. It was precipitated in the presence of 10 mmol / Ag mol. 10 times this emulsion mixture with water.
It was set to 0g. Adjust pH to 6.2 at 40 ° C and pAg at 40 ° C
Adjusted to 9.3. The mixture was then heated to 60 ° C. for 4 hours.

Figure 26E is an electron micrograph showing the resulting rather large raffle. The raffles consisted of crystal planes of pyramids in the {331} icosahedron crystallographic form.

Example 10 Emulsion Example 10 illustrates the preparation of a ruffled octahedral silver bromide emulsion using Compound (I) as a growth modifier.

To a reactor equipped with a stirrer was added 0.05 mol of an octahedral regular grain silver bromide emulsion containing 40 g / Ag mol of gelatin and having an average grain size of 1.35 μm. Water was added to bring the total weight to 50 g. To this emulsion at 40 ° C. was added 6.0 mmol of compound (I) / initial Ag mol dissolved in 2 ml of 1: 1 water-methanol. The emulsion was then held at 40 ° C for 15 minutes. pH 40
Adjusted to 6.0 at ° C. The temperature was raised to 60 ° C, the pAg was adjusted to 8.5 with KBr at 60 ° C and maintained at that value during precipitation. A 2.5 molar solution of AgNO ₃ was introduced at a constant rate over a 40 minute period, during which a 2.5 molar solution of KBr was added as needed to keep the pAg constant. A total of 0.02 mol Ag was added.

An electron micrograph of ruffled grains of the resulting emulsion
Shown in the figure.

Example 11 Emulsion Example 11 was prepared using the compound (VII) as a growth modifier.
Illustrates the preparation of a ruffled octahedral silver bromide emulsion using. The new surface formed indicates that, in addition to the formation of ruffles, the host particles began to grow into orthorhombic dodecahedra.

To a reactor equipped with a stirrer was added 0.05 mol of an emulsion of octahedral regular grain silver bromide containing about 10 g / Ag mol of gelatin and having an average grain size of 0.8 μm. Add water to bring the total weight to 50g
I made it. To this emulsion, at 40 ° C., 6.0 mmol of compound (VII) dissolved in 3 ml of methanol and 3 drops of triethylamine.
/ Ag mol was added. The emulsion was then held at 40 ° C for 15 minutes. The temperature was raised to 50 ° C and the pH was adjusted to 6.0 at 50 ° C. The pAg was adjusted to 8.8 with KBr at 50 ° C and maintained at that value during precipitation. A 2.0 molar solution of AgNO ₃ was introduced at a constant rate over a period of 70 minutes, during which KBr 2.0
Molar solution was added as needed to keep pAg constant.
A total of 0.014 mol Ag was added.

An electron micrograph of the resulting emulsion grains is shown in FIG. It can be seen that the octahedral faces of the host particles are uniformly ruffled. Furthermore, new planes have begun to form along the edges between the faces of the octahedra, indicating that the crystals are growing into {110} orthorhombic dodecahedrons.

Example 12 Emulsion Example 12 illustrates the preparation of a ruffled octahedral silver bromide emulsion using compound (X) as the growth modifier. The formation of icosahedrons became apparent when precipitation continued.

The host emulsion and procedure were the same as in Example 10. The growth modifier is a compound (X) 6.0 mmol / A dissolved in 3 ml of water.
It was g mol. For Example 12A, the precipitation time was 15 minutes and 0.0075 mol Ag was used. For Example 12B, the precipitation time was 30 minutes and 0.015 mol Ag was used.

29A and 29B are electron micrographs showing the emulsion grains obtained in Example 12A and Example 12B, respectively. In Example 12A, uniform raffles were formed over the faces of the octahedra, while new tetrahedron faces were formed along the edges between the original faces. In Example 12B, the process of forming the {331} icosahedron is almost complete.

Example 13 Emulsion Example 13 illustrates the formation of an octahedral silver bromide emulsion with increased surface area due to ruffles in the form of uniform ridges.

The host emulsion and procedure were the same as in Example 10. The growth modifier was 2.0 mmol of known green spectral sensitizing dye (XI) / initial Ag mol dissolved in 3 ml of methanol, 2 ml of water and 3 drops of triethylamine. The precipitation solution was 2.0 mol AgNO ₃ and KBr rather than 2.5 mol.

For Example 13A, the precipitation time is 200 minutes and Ag0.
04 mol was used. For Example 13B, the time was 350 minutes and 0.07 mol Ag was used.

30A and 30B show Examples 13A and 1 respectively.
3 is an electron micrograph of the resulting emulsion grains produced by 3B. The surface is evenly covered with ridges running perpendicular to the (110) Ag rows of the lattice. The twenty-four-sided face was beginning to form. In Example 13B, the ridge remains apparent, but the large macro habit is {331}.
It is a tetrahedron.

Example 14 Example 14 illustrates the preparation of ruffled cubic silver bromide grains using compound (XII) 2-mercaptoimidazole as a growth modifier. With continued growth, rhombohedral icosahedron grains were produced.

To a reactor equipped with a stirrer was added 0.05 mol of a silver bromide emulsion of cubic regular grains having an average grain size of 0.8 μm containing about 10 g / Ag mol of gelatin. Add water to bring the total weight to 50g
I made it. To this emulsion at 40 ° C. was added 3.0 mmol / Ag mol of compound (XII) dissolved in 3 ml of methanol. Then
The emulsion was held at 40 ° C for 15 minutes. The pH was adjusted to 6.0 at 40 ° C. Raise temperature to 60 ° C and pAg at 60 ° C in KBr 8.
Adjusted to 5 and maintained at that value during precipitation. AgNO ₃
2.5 molar solution was added at a constant rate over a period of 25 minutes, during which 2.5 molar solution of KBr was added as needed to obtain pAg.
Was held constant. Example with the addition of 0.0125 mol Ag in total
14A was formed. For Example 14B, precipitation continued for a total of 175 minutes, using a total of 0.0875 mol Ag. After 100 minutes precipitation time, a further 3 mmol / initial Ag mol of compound (XII) was added.

31A and 31B show examples 14A and 1 respectively.
4B is an electron micrograph of the resulting emulsion grains produced by 4B. FIG. 31A shows a growth pattern covering the crystal plane. FIG. 31B shows the formation of {533} rhombohedral tetrahedral grains upon continued precipitation.

Example 15 Example 15 was prepared by treating the compound (VII
Illustrates the preparation of a ruffled cubic silver bromide emulsion using I).

To a reactor equipped with a stirrer was added 0.05 mol of a silver bromide emulsion of cubic regular grains having an average grain size of 0.8 μm containing about 10 g / Ag mol of gelatin. Further, 10 g / Ag mol of deionized bone gelatin was added and the whole was made up to about 51 g with water.
To this emulsion at 40 ° C. was added 6.0 mmol of compound (VIII) / initial Ag mol dissolved in 3 ml of water and 3 drops of triethylamine. The emulsion was then held at 40 ° C for 15 minutes. Immediately before the start of precipitation, 1.0 ml of a 3.4 molar solution of (NH ₄ ) ₂ SO ₄ , concentrated NH ₄ OH1.75
ml and 0.5 ml of a 0.50 molar solution of KBr were added. pAg is 40 ° C
It was found to be 9.1 and was maintained at that value during precipitation. A 2.5 molar solution of AgNO ₃ was introduced at a constant rate over a period of 100 minutes, during which a 2.5 molar solution of KBr was added as needed to keep the pAg constant. 0.05 mol Ag total
Was added.

Figure 32 is an electron micrograph of the obtained emulsion grains.
The cube is slightly rounded and the sides of the cube are covered with uniform ruffles.

Example 16 This example illustrates the increase in photographic speed that can be achieved with ruffled particles according to the present invention.

Emulsion 16A of the Example A reactor equipped with a stirrer is charged with 0.05 mol of an octahedral silver bromoiodide emulsion containing 6 mol% of silver iodide having an average grain size of 0.3 μm and containing about 20 g / Ag mol of gelatin. did. Water was added to bring the total weight to 50 g. The emulsion was heated to 40 ° C. Consisting of 12 ml of water and 10 drops of triethylamine, N,
A solution of 0.625 mmol of a growth modifier of compound (V), a blue spectral sensitizing dye, in a solvent made up to 50 ml with N-dimethylformamide was prepared. Compound (V) 3.75 mmol /
A 15 ml portion of this solution containing the initial Ag moles was added to the emulsion which was then held at 40 ° C for 15 minutes. pH at 40 ° C 6.
Adjusted to 0. Raise temperature to 60 ° C and pAg at 60 ° C KB
Adjusted to 8.5 with r and maintained at that value during precipitation. Ag
A 2.0 molar solution of NO ₃ was introduced constantly over a period of 67 minutes, during which a solution with a KBr of 1.88 moles and a KI of 0.12 moles was added as needed to keep the pAg constant. A total of 0.013 mol Ag was added. The resulting emulsion was then centrifuged and resuspended in 40 ml of 3% deionized bone gelatin solution.

FIG. 33A is an electron micrograph of the obtained octahedral emulsion of ruffle grains.

Control Emulsion 16B Control Emulsion 16B was prepared as described for Example Emulsion 16A, but without the growth modifier [Compound (V)] present during precipitation. After precipitation, compound (V) 1.
25 mmol was added. This amount is typical for sensitizing dyes for emulsions of this grain size.

FIG. 33B is an electron micrograph showing the obtained regular octahedral grains. No ruffled grain surface is identified.

Control Emulsion 16C A portion of Control Emulsion 16B was modified after precipitation, but before coating, by increasing the total content of Compound (V) to 3.75 mmol / Ag mol, which is equal to its concentration in Example Emulsion 16A. did.

1.18 g / silver of each of the emulsions on a cellulose acetate support.
It was coated with m ² and gelatin 4.20 g / m ² . A sample of the coating,
Graduated tablet
Exposure to a 365 nm filtered mercury light source for 0.5 seconds to obtain a measure of intrinsic sensitivity, and exposure to a Ratten 47 filtered tungsten light source to obtain blue sensitivity. An Eastman 1B sensitometer was used. The exposed sample was developed at 20 ° C. in Kodak Rapid X-ray development for 6 minutes. The difference between the blue sensitivity and the 365 nm sensitivity is taken as a measure of the relative degree of spectral sensitization for each of the three coatings and is listed in Table V.

As the data show, Example Emulsion 16A has an amount of sensitizing dye equal to that of the control unruffled emulsion 16B and the ruffled grain Example Emulsion 16A, each with normal spectral sensitization. Had a significantly greater blue sensitivity with respect to its 365 nm sensitivity.

Comparative Example 17 The purpose of this Comparative Example is to report the results of adding 6-nitrobenzimidazole to the reactor prior to silver bromide precipitation, as suggested by U.S. Pat. No. 1,696,830 to Wulff et al. Is.

0.75g deionized bone gelatin in a reactor equipped with stirrer
Was added and made up to 50 g with water. 6 dissolved in 1 ml of methanol
16.2 mg of nitrobenzimidazole (0.3% by weight based on Ag used) were added, followed by 0.055 mol of KBr. At 70 ° C, 0.05 mol of a 2 mol solution of AgNO ₃ was added at a uniform rate to 2
Added over a 5 minute period. The grains formed were relatively thick slabs and exhibited {111} crystal faces. There was no indication of the ruffled crystal planes of the present invention.

Comparative Example 18 The purpose of this comparative example was to recite the Smith (Smit) quoted above.
h), growth and suspension of particles (Particle Growth and Sus
As the pension suggests, it is to report the results using 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene, sodium salt during precipitation of the particles.

To 100 ml of a 3% bone gelatin solution, 10 ml of 1.96 mol AgNO _{3 and} 10 ml of 1.96 mol KBr were added simultaneously with stirring at 50 ° C. over a period of about 20 seconds. The AgBr dispersion was aged at 50 ° C. for 1 minute and then diluted to 500 ml. This dispersion is K
Br was adjusted to pBr3.

Sample 18a, 18b 1 × 10 ^-3 containing 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene sodium salt 0.4 mmol / l and 1-dodecylquinolinium bromide 0.6 mmol / l
To 80 ml of molar KBr was added 20 ml of the above dispersion, which was then stirred at 23 ° C. Samples were removed after 15 minutes (Sample 18a) and 60 minutes (Sample 18b).

Samples 18c, 18d Samples 18c and 18d were prepared in the same manner as samples 18a and 18b, respectively, except that 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene 0.8 mmol / l and bromide 1 -0.6 mmol / l dodecylquinolinium was used.

Examination of the particles in each of the samples revealed that the particles were rounded cubes. No ruffled crystal faces were observed.

〔The invention's effect〕

The present invention makes available silver halide grains in the art which provide a surface of increased area and which have a crystallographic morphology different from that favored by the silver halide forming the grain surface. Each of these surface features offers its distinct advantages.

First, a high particle surface area ratio is realized. While reliant on refining the particles in the art to increase the surface area ratio, the present invention allows increasing the surface area ratio of the particles independent of particle size. Moreover, the surface area ratio can be increased independently of the overall particle shape.
In particular, the increase in grain surface area ratio due to the ruffled main crystal planes contemplated by the present invention is equally applicable to otherwise regular or irregular cubic or octahedral grains.

Moreover, the novel ruffle formation approach of the present invention and other known approaches of increasing particle surface area ratio, which specifically reduce particle size or provide irregular particle shape, are comparable. , And in combination,
The particle surface area ratio can be additionally increased.

The grain surface area ratio of thin or high aspect ratio tabular grain emulsions can be increased by forming ruffled grain faces as contemplated by this invention. This results in an emulsion with a greater surface area ratio than previously realized for the corresponding grain size.

At the same time, the present invention enables an increase in particle surface area ratio without depending on the shape of plate-like particles. The present invention offers particular advantages when applied to regular and other non-platelet particle shapes.

The second salient silver halide grain surface feature of the present invention modifies the photographic properties, thus allowing the selection of variegated and novel crystallographic forms at the grain surface.
As an example, silver chloride strongly prefers a cubic crystal morphology, but the present invention allows for other crystallographic morphologies in the silver chloride grain plane to match the structure of the cubic crystal lattice. As a second example, thin and high aspect ratio tabular grain emulsions most easily occur for octahedral crystal faces, but the present invention provides other crystallographic morphologies compatible with the cubic crystal lattice structure. It can be realized on the surface of particle.

The present invention provides the advantage that both high surface area ratios and grain faces of different crystallographic morphologies can be realized simultaneously. This combination allows the realization of emulsions with unique and varying photographic properties.

[Brief description of drawings]

FIG. 2 is a schematic diagram of the atomic arrangement on the cubic crystal plane of silver bromide. FIG. 3 is an isometric view of regular octahedral silver halide grains. FIG. 4 is a schematic diagram of the atomic arrangement on the octahedral crystal plane of silver bromide. FIG. 5 is an isometric view of a regular orthorhombic dodecahedron. FIG. 6 is a schematic view of the atomic arrangement on the crystal plane of a silver bromide orthorhombic dodecahedron. FIG. 7 is an isometric view of regular cubic silver halide grains, regular octahedral silver halide grains, and intermediate cubic-octahedral silver halide grains. 8 and 9 are plan views of the protrusions of the pyramid from the base surface. FIG. 10 is an isometric view of regular {331} icosahedron silver halide grains. FIG. 11 is a schematic view of atomic arrangement of {331} silver bromide rhombohedron tetrahedron. FIG. 12 is an isometric view of regular {210} tetrahedral silver halide grains. FIG. 13 is a schematic view of the atomic arrangement on the crystal plane of a silver bromide {210} tetrahedron. FIG. 14 is an isometric view of regular {211} rhombohedral tetradecahedral silver halide grains. FIG. 15 is a schematic diagram of the atomic arrangement on the crystal plane of the {211} rhombohedral tetrahedron of silver bromide. FIG. 16 is an isometric view of regular {321} hexahedral silver halide grains. FIG. 17 is a schematic view of the atomic arrangement in the crystal plane of the silver bromide {321} hexaoctahedral. FIG. 18 is an isometric view of regular cubic silver halide grains. Figure 1, Figure 19, Figure 20, Figure 21A, Figure 21B, and Figure 21C
Figure, Figure 21D, Figure 22, Figure 23A, Figure 23B, Figure 23C,
24A, 24B, 24C, 24D, 25, 26A
Fig. 26B, 26C, 26D, 26E, 27,
28, 29A, 29B, 30A, 30B, 31A
FIG. 31, FIG. 31B, FIG. 32, FIG. 33A and FIG. 33B are electron micrographs of silver halide emulsion grains. 1 ... Cubic particles, 2 ... Silver ions, 3 ... Bromine ions, 4,8a and 8b ... Rows, 5 ... Octahedral particles, 7 ...
Orthorhombic dodecahedron grains, 9 and 10 ... Cubic-octahedral grains, 11a, 11b and 11c ... {100} crystal faces, 12 ...
… Base plane, 13a, 13b, 13c and 13d …… {111} crystal plane, 14
…… Base plane, 15 …… Icosahedron, 16 and 17 …… Granular angle, 16
a, 16b, 16c, 17a, 17b, 17c, 17d, 17e and 17f …… Idecahedron crystal face, 18 …… Tetrahedra, 19 and 20 …… Protrusion angle, 19
a, 19b, 19c, 19d, 20a, 20b, 20c and 20d …… Crystal face of tetrahedron, 21 …… Hybrid icosahedron, 22 and 23 …… Protrusion angle, 22
a, 22b, 22c, 22d, 23a and 23b …… Crystal face of rhombohedral icosahedron, 24 …… hexahedral, 25,26 and 27 …… real angle, 25a, 25
b, 25c, 25d, 25e, 25f, 25g, 25h, 26a, 26b, 26c, 26d and 27a
…… A hexahedral crystal plane.

Claims (1)

[Claims] 1. A silver halide grain having a cubic crystal lattice structure, wherein the silver halide grain is a protrusion that is an extension of the silver halide crystal lattice from a base plane of the first crystallographic morphology. Grain having a ruffled surface according to the present invention and adjacent to the base surface below the base surface and in the protrusion exhibit the same silver halide composition, and the protrusion has a second crystallographic morphology. A radiation-sensitive emulsion that provides a surface.