GB2052770A - Silver Halide Photographic Material Providing an Image and an Unsharp Mask - Google Patents
Silver Halide Photographic Material Providing an Image and an Unsharp Mask Download PDFInfo
- Publication number
- GB2052770A GB2052770A GB7927142A GB7927142A GB2052770A GB 2052770 A GB2052770 A GB 2052770A GB 7927142 A GB7927142 A GB 7927142A GB 7927142 A GB7927142 A GB 7927142A GB 2052770 A GB2052770 A GB 2052770A
- Authority
- GB
- United Kingdom
- Prior art keywords
- emulsion
- silver halide
- film
- layer
- image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 24
- 239000004332 silver Substances 0.000 title claims abstract description 24
- -1 Silver Halide Chemical class 0.000 title claims abstract description 18
- 239000000463 material Substances 0.000 title description 8
- 239000000839 emulsion Substances 0.000 claims abstract description 63
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 239000002667 nucleating agent Substances 0.000 claims description 2
- 230000001376 precipitating effect Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 5
- 239000004133 Sodium thiosulphate Substances 0.000 description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 5
- 239000010931 gold Substances 0.000 description 5
- 229910052737 gold Inorganic materials 0.000 description 5
- 230000000873 masking effect Effects 0.000 description 5
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 5
- 235000019345 sodium thiosulphate Nutrition 0.000 description 5
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000000975 dye Substances 0.000 description 3
- ADZWSOLPGZMUMY-UHFFFAOYSA-M silver bromide Chemical compound [Ag]Br ADZWSOLPGZMUMY-UHFFFAOYSA-M 0.000 description 3
- LRUDIIUSNGCQKF-UHFFFAOYSA-N 5-methyl-1H-benzotriazole Chemical compound C1=C(C)C=CC2=NNN=C21 LRUDIIUSNGCQKF-UHFFFAOYSA-N 0.000 description 2
- CBEQRNSPHCCXSH-UHFFFAOYSA-N iodine monobromide Chemical compound IBr CBEQRNSPHCCXSH-UHFFFAOYSA-N 0.000 description 2
- AJDUTMFFZHIJEM-UHFFFAOYSA-N n-(9,10-dioxoanthracen-1-yl)-4-[4-[[4-[4-[(9,10-dioxoanthracen-1-yl)carbamoyl]phenyl]phenyl]diazenyl]phenyl]benzamide Chemical compound O=C1C2=CC=CC=C2C(=O)C2=C1C=CC=C2NC(=O)C(C=C1)=CC=C1C(C=C1)=CC=C1N=NC(C=C1)=CC=C1C(C=C1)=CC=C1C(=O)NC1=CC=CC2=C1C(=O)C1=CC=CC=C1C2=O AJDUTMFFZHIJEM-UHFFFAOYSA-N 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000001043 yellow dye Substances 0.000 description 2
- 229920000623 Cellulose acetate phthalate Polymers 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical group [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- PQTCMBYFWMFIGM-UHFFFAOYSA-N gold silver Chemical compound [Ag].[Au] PQTCMBYFWMFIGM-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- CMCWWLVWPDLCRM-UHFFFAOYSA-N phenidone Chemical compound N1C(=O)CCN1C1=CC=CC=C1 CMCWWLVWPDLCRM-UHFFFAOYSA-N 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 229940080262 sodium tetrachloroaurate Drugs 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
- G03C5/16—X-ray, infrared, or ultraviolet ray processes
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C1/00—Photosensitive materials
- G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
- G03C1/46—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein having more than one photosensitive layer
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Abstract
Desirable edge effects are produced by normal imagewise exposure and processing of a sensitive radiographic film comprising a transparent film support bearing a layer of a direct-positive silver halide emulsion and a layer of a negative silver halide emulsion and wherein the film comprises means to reduce cross- over between the two emulsion layers, one of said emulsion layers being adapted to record a primary image and the other being adapted to record an unsharp mask image.
Description
SPECIFICATION Radiographic Silver Halide Materials
This invention relates to radiographic silver
halide materials.
In image recording systems the contrast of fine
detail is generally lower than the contrast of
coarse detail because of image spread, as
indicated by a decrease in the modulation transfer
function (MTF) with increasing image frequency.
This phenomenon has been compensated for by
exploiting a number of so-called edge effects
which make the fine detail of an image appear
sharper.
One method for obtaining desirable edge
effects in photographic silver halide materials is
by restricting the rate at which developer in the
emulsion layer is replenished and the rate at
which development products in the. emulsion
layer are removed.
Another method is know as "unsharp
masking" and is described in "Principles of Colour
Reproduction" by J. A. C. Yule, Wiley, New York, 1967,. pages 74-8. Briefly, the unsharp masking
of a photographic transparency is normally
achieved by making mask, which is an out-of
focus negative copy, and then superimposing the mason the original transparency. The mask,
being unsharp, does not contain any high
frequency information (fine-detail) so that when
superimposed on the original produces a
reduction in contrast of the low frequency
information.
A high contrast copy of the combination may
then be made which recovers the original contrast
of the low frequencies while increasing the
contrast of the high frequencies. Alternatively, if
the original transparency is more contrasty than
finally desired, the combination may be viewed
directly at the desired contrast without making a
copy.
The degree of masking will depend on the
relative contrasts and saturation densities of the
materials used to make the original transparency
and the mask.
The present invention provides a sensitive
radiographic material which is capable of
providing a primary image and an unsharp mask
simultaneously thus producing an image showing
edge effects.
According to the present invention there is
provided a sensitive radiographic film comprising
a transparent film support bearing a layer of a
direct-positive silver halide emulsion and a layer
of a negative silver halide emulsion and wherein the film comprises means to reduce crossover
between the two emulsion layers, one of said emulsion layers being adapted to record a primary
image and the other being adapted to record an unsharp mask image.
The present films may be designed to produce either direct-positive or negative primary images
provided respectively with negative or direct
positive unsharp masks.
Cross-over is a well known phenomenon in radiographic films and refers to the exposure of one emulsion layer by radiation intended only to expose a neighbouring emulsion layer. Often in radiographic films such emulsion layers are coated on opposite sides of the film support.
Cross-over is reduced either by use of a tinted support or by the presence of a light-absorbing "antihalation" layer between one emulsion layer and the support.
The present radiographic films may have both emulsion layers coated on the same side of the support separated by a light-absorbing layer to reduce cross-over. Alternatively the two layers are coated on opposite sides of the support with a light-absorbing layer or coloured support between them.
A particularly preferred light-absorbing layer comprises a dye which is bleached during processing. Such dyes have been used in conventional antihalation layers.
Cross-over may also be reduced by employing.
emulsion layers sensitive to different portions of the spectrum. Such films could be exposed using phosphor screens emitting light of different wavelengths. Alternatively, one light-emitting phosphor screen could be used while the other emulsion layer is exposed directly to X-rays.
The primary image may be formed by exposing the primary image emulsion layer either directly to X-rays or by using a high resolution phosphor screen. At the same time the unsharp masking layer is exposed using.another phosphor screen, possibly of-lower resolution and usually with a spacer to produce the desired degree of unsharpness.
It will be appreciated that the magnitude of the edge effects obtained will depend on the relative speeds and maximum densities of the-two emulsion layers, the relative speeds of the phosphor screens used and the effect of the means for reducing cross-over. The spacing of the screen for the masking image and its resolution will determine the image frequencies at which the sharpening edge effects are seen.
The negative silver halide emulsions which may be employed in the present inventions may be monodisperse or polydisperse developing out emulsions and may be made by known methods.
Such emulsions and their associated technology are described in Product Licensing Index, Vol, 92,
December 1971, publication 9232.
The direct-positive emulsions employed herein may be of any type provided that a direct-positive image is.provided during a single development step.
The direct-positive silver halide emulsions employed in the present invention may also be monodisperse or polydisperse developing out emulsions and may be fogged and be of the solarisation or sensitized Herschel Type. Such emulsions are described in British Specifications Nos. 1,151,781, 1,186,711--3, and 1,186,718.
They may also be "internal-image" emulsions which, when processed in the presence of nucleating agents, produce a direct positive
image. Such emulsions are often also termed
"direct reversal" emulsions and are described in
U.S. Patent Specifications 2,592,250 and 3,761,276.
A direct-positive image may also be obtained
by using a negative silver halide emulsion of low
coating weight, e.g. dilute, containing gold silver
precipitation nuclei. When such an emulsion is
developed in a developer containing a silver
halide solvent a direct-positive image is obtained.
The film support for the present radiographic
materials may, for example, be composed of a
cellulose acetate or polyethyleneterephthalate, a
polycarbonate, polysulphone or polyolefin.
The present films may also contain sub-layers
and supercoat layers as in conventional
photographic materials.
In one preferred form of the present invention
the radiographic film has the structure:
negative emulsion
film base
antihalation layer
direct reversal emulsion
The direct reversal emulsion is prepared as
follows. Octahedral cores of silver bromide are
chemically sensitized by digesting in the presence
of sodium thiosulphate and sodium
tetrachloroaurate. The grain size is then increased
to 0.8 #m diameter by further additions of silver
bromide and the emulsion is sensitized again by
digesting in the presence of sodium thiosulphate.
Avnucleator is added to the emulsion prior to
coating the emulsion at a level of 2 g silver m-2.
The negative emulsion is a conventional ammoniacal iodobromide emulsion of mean grain
area 0.8 ,um2 that is sulphur and gold sensitized
and coated at a level of 2.5 g silver m-2 to give a
saturation density of 1.0 as in the case of the
direct reversal emulsion.
The antihalation layer comprises a developer
bleachable yellow dye with a maximum density of
1.8 which is coated in a manner to prevent it
diffusing into the adjacent emulsion layer.
The composition of a suitable developer is
shown in Table 1. The presence of the nucleator
in the film and the antifoggant in the developer
(5-methyl benzotriazole) promote the formation of
a positive image in the silver bromide emulsion.
Any unwanted effect of these components on the
iodobromide emulsion is minimal. The film is fixed
and washed in the normal way and at some stage
during the process the yellow dye is bleached.
Table 1
Hydroquinone 10 g Metoi 5g Anhydrous sodium sulphite 75 g
Sodium hydroxide 10.5 g
5-methyl benzotriazole 0.2 g
Tri-sodium phosphate 75 g
Water to 1000 ml
In another preferred form of the present invention the radiographic film has the structure:
negative emulsion
film base
c
antihalation layer
dilute negative emulsion
and gold nuclei
The film comprises a conventional negative type emulsion and an emulsion layer capable of producing a positive image by solution physical development.
The positive image is produced as follows. A negative ammoniacal emulsion of coarse grain and low covering power is coated at a level of 1 g silver m to give a saturation density of 0.3. This emulsion layer also contains gold nuclei of 5x 10-9 m diameter at a level of 16 mg gold m-2.
During development of the layer silver ions in solution physically develop onto the gold nuclei to produce silver specks of high covering power that yield a positive image with a saturation density of 4.0.
The negative emulsion is also an ammoniacal emulsion but it is of finer grain than the emulsion used to produce the positive image and it is coated at a level of 7 g silver m-2 to give a saturation density of 3.0.
The antihalation layer is a developerbleachable layer as described above.
A Asuitable developer is shown in Table 2. The purpose of the sodium thiosulphate is to dissolve the undeveloped silver halide in the dilute emulsion which promotes solution physical development and produces the positive image.
Table 2
Phenidone (Registered Trade
Mark) 2 9 Hydroquinone 10 g Sodium thiosulphate 4 g
Anhydrous sodium sulphite 50 g
Sodium hydroxide to pH 12.8
Water to 1000 ml
The image produced in the negative emulsion of high coating weight is not adversely affected by the presence of sodium thiosulphate so that both the positive and the negative images are developed simultaneously. The developer also bleaches the dye.
Claims (8)
1. A sensitive radiographic film comprising a transparent film support bearing a layer of a direct-positive silver halide emulsion and a layer of a negative silver halide emulsion and wherein the film comprises means to reduce cross-over between the two emulsion layers, one of the said emulsion layers being adapted to record a primary image and the other being adapted to record an unsharp mask image.
2. A radiographic film as claimed in claim 1 in which the two emulsion layers are coated on opposite sides of the film support.
3. A radiographic film as claimed in claim 1 or 2 in which the means to reduce cross-over comprises a light-absorbing layer located between the two emulsion layers.
4. A radiographic film as claimed in claim 3 in which the light-absorbing layer comprises a dye which is bleached during processing.
5. A radiographic film as claimed in claim 2 in which the means to reduce cross-over comprises a tinted support.
6. A radiographic film as claimed in any of claims 1-5 in which the direct-positive emulsion comprises internally sensitive silver halide grains and a nucleating agent.
7. A radiographic film as claimed in any of claims 1-5 in which the direct-positive emulsion comprises a negative silver halide emulsion layer of low coating weight containing silver precipitating nuclei.
8. A radiographic film substantially as described herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7927142A GB2052770B (en) | 1978-08-03 | 1979-08-03 | Silver halide photographic material providing an image and an unsharp mask |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7832192 | 1978-08-03 | ||
| GB7927142A GB2052770B (en) | 1978-08-03 | 1979-08-03 | Silver halide photographic material providing an image and an unsharp mask |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2052770A true GB2052770A (en) | 1981-01-28 |
| GB2052770B GB2052770B (en) | 1982-09-22 |
Family
ID=26268442
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7927142A Expired GB2052770B (en) | 1978-08-03 | 1979-08-03 | Silver halide photographic material providing an image and an unsharp mask |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2052770B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0345766A2 (en) * | 1988-06-10 | 1989-12-13 | E.I. Du Pont De Nemours And Company | Unsharp masking of diagnostic radiation intensifying screens |
-
1979
- 1979-08-03 GB GB7927142A patent/GB2052770B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0345766A2 (en) * | 1988-06-10 | 1989-12-13 | E.I. Du Pont De Nemours And Company | Unsharp masking of diagnostic radiation intensifying screens |
| EP0345766A3 (en) * | 1988-06-10 | 1990-10-24 | E.I. Du Pont De Nemours And Company | Unsharp masking of diagnostic radiation intensifying screens |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2052770B (en) | 1982-09-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |