GB2089054A - Photographic colour process - Google Patents

Abstract

The invention provides a photographic colour image which is masked to improve the sharpness thereof by the addition of edge effects. The main impression of sharpness comes from a luminance variation at the edge of the image. In the invention desirable effects are obtained by superposing a sharp retained dye image upon its complementary unsharp dye image of opposite sense obtained by diffusion transfer. In particular there is provided a photographic element comprising a support and containing a colour image and a mask therefor which produces edge effects and whereof a first component is a diffusion transfer image formed of a masking dye of neutral or degraded colour and whereof a second component is a sharp retained image formed of said masking dye and of the same sign as said colour image.

Description

SPECIFICATION Photographic colour process This invention relates to photographic masked colour images useful for the production of prints therefrom and to materials and processes for making such colour images.

The unsharpness of a transferred dye image arises partly from the distance the dye has to diffuse from its point of origin in the exposed light-sensitive silver halide unit, which provides the dye on development, to the receiving layer in which the colour transfer image is thus formed. The greater this distance the more the dye spreads.

In addition, the latent image in the lower lightsensitive layers of a multilayer pack is rendered less sharp on exposure by increased scattering as the light penetrates down into the pack. Thus, if the yellow dye-providing unit is on the top of the pack, the yellow dye image will be sharper than the magenta and cyan dye images.

The main impression of sharpness comes from a luminance variation at the edges of the images. It is an object of this invention to improve the sharpness of a colour transfer image by addition of edge effects.

We have found that by superposing a sharp retained dye image upon its complementary unsharp diffusion transfer dye image of opposite sense (i.e. negative v positive) desirable edge effects can be produced.

According to the present invention there is provided a dye-receiving element containing a colour transfer image in a layer of the element and containing also a mask whereof a first component is a transfer image formed of a masking dye of neutral or degraded colour in said layer and whereof a second component is a sharp image formed of said masking dye in an adjacent layer, said three images being derived from one light image, said first component transfer image being of the opposite sign to said colour transfer image and said second component sharp image being of the same sign as said colour transfer image and as sharp as possible.

In an imaged dye-receiving element of this invention the transfer image slightly overlaps the sharp image giving rise to an increase in density at the edges of the colour transfer image and thus providing the required edge effect.

In the element of the invention containing a colour transfer image there is no major change in contrast due to the presence of the mask of the invention because the sum of the two images constituting the mask is constant except at the edges. Also colour saturation is not reduced by the mask except for very fine detail where colour saturation is not important.

The colour transfer image plus mask of the invention can be used for the production of pictures of improved sharpness. Preferably the colour transfer image is a negative.

Preferably in the dye-receiving element of the invention a spacer layer is provided between the mordant layer and the layer which is to contain the sharp retained image i.e. the second component of the mask, when these are distinct layers. The microdensity profile of the edge will depend on the relative unsharpness of the transferred mask image, which in turn will be controlled by the distance over which the dyes migrate. Thus, by varying the thickness of the spacer layer and the density of the masking dyes the profile may be adjusted to achieve the effect desired.

Preferably, in a dye-receiving element of the invention comprising a support, the layer which is to contain the second component of the mask is outermost from the support.

The colour transfer image in the element of this invention can be made of dyes of one or more colours and the colours may be the subtractive colours, i.e. yellow, magenta and cyan, usually associated with the blue- green- and red-sensitive layers, respectively, in a multilayer colour film.

The masking dye should preferably have a density of half that of the maximum density of the main image, although useful effects may be obtained at lower densities, and the dye or dyes should preferably be monochrome to avoid fringing, although it is not necessary that the colour should be absolutely neutral.

The neutral colour of the mask can be grey but it can also be a degraded colour if it is desired to add an edge effect to the image formed by only some of the colours in a multicolour image. Thus, the mask will be a degraded blue colour if it is desired to add an edge effect to the magenta plus cyan components of a multilayer subtractive colour image.

According to the present invention there is also provided a method of making a dye-receiving element containing a colour transfer image which comprises exposing and developing a light-sensitive silver halide emulsion layer with which is associated a dye-providing compound such that an imagewise distribution of diffusible image dye is formed on said development, allowing at least some of said imagewise distribution of diffusible image dye to transfer in register to a mordant layer and which comprises exposing to the same light image a lightsensitive silver halide emulsion layer with which is associated in an adjacent layer a compound of neutral or degraded colour such that an imagewise distribution of diffusible dye also of neutral or degraded colour is formed on said development and which is of opposite sign to said imagewise distribution of diffusible image dye and allowing at least some of said diffusible neutral dye or dye of the degraded colour to transfer in register into said mordant layer and thus also forming a retained image of said neutral dye or dye of degraded colour in said adjacent layer, and associating said retained image in register with said transferred diffusible image dye in said mordant layer.

By this method the diffusible image dye which transfers to the mordant layer forms the colour transfer image, the diffusible neutral or degraded colour dye forms the first component of the mask and the retained image forms the second component of the mask.

Preferably, in the method of the present invention all said light-sensitive silver halide emulsion layers are on the same support.

Preferably, the light-sensitive silver halide which is to control the imagewise formation of the masking dye is separated from the other light-sensitive layer by a scavenger layer for oxidised developing agent.

When all the light-sensitive layers are in one support the layer which is to contain the second component of the mask and the mordant layer which is to contain the colour transfer image and the first component of the mask are all on another support.

In orderto carryoutthis preferred method of the invention in one embodiment, the silver halide emulsion with which is associated the compound providing the neutral or degraded colour image is coated over the other silver halide emulsion layers with a scavenger layer for reacting with oxidised developing agent between it and said other emulsion layers. The layer containing said compound is coated over the mordant layer. The method can then be carried out by treating the two elements with a liquid processing composition while maintaining the layer containing said compound in face-to-face relationship with the photosensitive layers with the processing composition spread between them.

However, the silver halide emulsion with which the masking dye-providing compound is associated may be coated over the layer which is to contain the second component of the mask or may be coated with the masking dye-providing compound in the same layer. In this case the image-receiving element must be exposed and processed in register with the main colour transfer image-forming element, and the silver image subsequently removed from the mask-forming layer.

In a preferred embodiment of the method of the invention a multilayer photographic element is used comprising a blue-, a green- and a red-sensitive negative-working emulsion layer and compounds associated therewith which provide on development, respectively, a diffusible yellow, a diffusible magenta and a diffusible cyan image dye and comprising a pan-sensitive direct positive emulsion layer separated from the other layers by a scavenger layer for oxodised developer. There is also used a dyereceiving element comprising a mordantlayerfor said image dyes and, over the mordant layer, a layer which contains a negative-working compound or compounds, which on reaction with oxidised developing agent yields a neutral dye or mixture of dyes.

On development yellow, magenta and cyan dyes are liberated in the light-struck areas of the negative-working emulsion layers and oxidised developing agent is liberated in non-light-struck areas of the pan-sensitive emulsion layer which diffuses into the upper layer of the dye-receiving ele ment containing the compound which provides the neutral dye on oxidation. There is thus formed an imagewise distribution of diffusible neutral dye of opposite sign to the distribution of image dyes and a retained image of neutral dye of the same sign as the image dyes i.e. of the same sign as the colour transfer image.

In another embodiment of the method of the invention a light-sensitive silver halide emulsion layer is used with which is associated a compound such that an imagewise distribution of non-diffusible image dye is formed on development which dye is produced by reaction of said compound e.g. a colour coupler, with oxidised colour developing agent.

Such emulsion layers are present in films sold under the registered trade mark 'Kodacolor'. To carry out the method such a film is provided with (i) an additional pan-sensitive silver halide emulsion layer with which is associated, e.g. in the same layer, a compound which liberates diffusible masking dye in the non-light-struck areas of the pan-sensitive layer and (ii) a mordant layerforthe masking-dye. Preferably the pan-sensitive layer is coated on top of the main emulsion layers to give the sharpest possible retained image, and the compounds which liberate diffusible dye are transparent or in a spectrally shifted form so as not to absorb the exposing light.

The pan-sensitive layer can be a direct positive emulsion layer in which case the compound is negative-working i.e. liberates diffusible dye on reaction with oxidised colour developing agent or can be a negative-working emulsion layer in which case the compound may be such as to liberate diffusible dye on reaction with alkaline processing composition unless prevented from doing so by rapid reaction with oxidised colour developing agent.

The mordant layer may be spaced from the layer containing the masking dye-providing compounds to give the required mask density profile as disclosed above. Thus it may be coated below the main image recording emulsion layers or at any intermediate position.

The structures of one embodiment of a photographic element of the invention and a dye-receiving element (not yet imaged) designed for use in the method of the invention are shown in Fig. 1 of the accompanying drawings.

The manufacture of the photographic and dyereceiving elements involves coating a scavenger layer B and pan-sensitized emulsion layer C on top of the normal image forming layers of the donor A.

Also a layer D capable of releasing a neutral dye or dyes is coated on top of the mordant receiver E. For a main colour transfer image formed from negative emulsions and negative chemistry, layer C should be a direct positive emulsion unless a positive working chemistry is used in layer D. Exposure of the donor additionally records a sharp image in the added pan emulsion layer and is used to produce (a) a sharp retained dye image in the dye releasing layer D and (b) an unsharp transferred dye image in the mordant layer E.

As shown in Fig. 2 of the accompanying drawings the predicted result of two such images (a) and (b) is a pronounced edge effect. This "masking" image combined with the main colour image (originating from layer A) should improve sharpness without degrading the colours or changing the contrast.

It will be observed from Fig. 2 that the edge effects occur on a constant density background. As a result this method of masking is particularly useful in a diffusion transfer negative for making prints but may also be useful in a positive transparency if the background is neutral and not too high.

If, in another embodiment of the invention, layer D were coated with layer C on the donor using a direct positive emulsion it would generate a relatively sharp positive transferred image on the mordant E.

The sum of this image and the main colour transfer image would give enhanced sharpness upon printing, but the contrast of the main colour transfer image would be reduced.

The following Examples exemplify but do not limit the present invention.

Examples 1 and 2 describe two dye-receiving elements of the invention and method of forming a masked colour transfer image in them according to the invention. Example 3 describes dye-receiving elements of the invention and another use thereof according to the invention.

Examples 1 and 2 These Examples demonstrate the functioning of layers C, D and E (Fig.1) in isolation from layers A.

i.e. the technique of masking.

The following dye-receiving elements of the invention were prepared: Receiver A Units: mgs/s. metre Gel - 1200 CyanRDR(Cl) 260 Magenta RDR (MI) 400 Yellow RDR (Yl) 400 BVSME 18 Mordant 5380 Gel (pig) 5380 BVSME 108 lill/Antistatic 'Estar'lIlIll ReceiverB Units: mgs/sq. metre Gel 1200 Cyan RDR (C2) 260 Magenta RDR (MI) 300 Yellow RDR (Y2) 400 BVSME 18 Mordant 3500 BGE 174 pH5.5 gel 3500 HCHO 245 Mordant 3500 BGE 174 gel 3500 pH 5.5 HCHO 245 ETA 215 l//I/Antistatic'Estar' IIIII The redox dye releasers used were as follows:

In the case of C1 the RDR was dispersed in di-nbutyl phthalate and for C2 the same compound was dispersed in N,N-diethyl lauramide.

Magenta (M1)

The RDR was dispersed in N,N-diethyllauramide.

Yellow (Y1 )

The RDR was dispersed in 1,4 cyclohexanedimethyl bis(2-ethylhexanoate).

Yellow (Y2)

The RDR was dispersed in N,N-diethyl lauramide.

Mordants X poly(styrene co - N -vinylbenzyl - N benzyl - N,N - dimethyl - ammonium chloride-co -1,4 - divinylbenzene.

Y poly(1 -vinylimidazole) partially (ca 10%) quaternized with chloroethanol.

Hardeners BGE butanediol diglycidyl ether.

BVSME bis(vinyl sulphonyl methyl) ether.

HCHO formaldehyde.

Developer ETA 1 - phenyl - 4 - hydroxymethyl - 4 methyl - 3 - pyrazolididone.

It was found that both the elements A and B were soft and had to be prehardened before use. This was done by soaking the coatings in the C41 'Kodacolor' prehardener for 3K at 704 followed by washing and drying; normally this procedure would not be necessary.

The donor coating (represented by layer C in Fig.

1) was a coating of a silver chlorobromide emulsion (35% Br, 65% Cl 0.3cm), in gel (Ag 4.0 glum,, gel 4.8 g/m2) overcoated with a supercoat of gel (1 g/m2).

Emulsion and supercoatwere coated on 0.006 inch 'Estar' backed with a dyed pelloid layer. The emulsion was ortho-sensitized for ease of handling.

Process The following developer was used: KOH 56.0 g 5-methylbenzotriazole 3.0 g KBr 2.0 g 11-aminoundecanoic acid 2.0 g ETA 8.0g Waterto 1000 ml HEC (Hydroxyethyl cellulose) 28 g The undercut roller method of processing was used.

The donor coating was exposed to a knife edge placed across a normal silver sensitometric wedge.

Care was taken to ensure good contact between the donor emulsion and the knife edge during exposure.

The exposed coating was then laminated to a prehardened sheet of receiver A using the developer and a 0.002 inch undercut roller. Development was allowed to proceed for 20 minutes at 70 F followed by peel apart. The donor was washed, fixed, washed and then dried, while the mordant was spray rinsed to remove developer and dried. A microdensitometertrace was made across the edge (DmaxtO Dmin) of both the silver image on the donor and dye image on the mordant, and is shown in Fig. 3 of the accompanying drawings. The silver image showed a pronounced edge effect. The dye image showed the symmetrical double ears shown in Fig. 2.

Example 3 The donor coating was exposed to 1000, 100 and 10 micron X-ray lines. The exposed coating was then laminated to a prehardened sheet of receiver B. A 0.003 inch undercut roller was used and development and subsequent treatment was carried out as described in Example 1. The microdensitometer traces of the silver and dye images are shown in Figs. 4, 5 of the accompanying drawings. The silver image (Fig. 4) showed marked conventional edge effects, while the dye image (Fig. 5) showed the symmetrical "double ears" for the 1000 micron line.

For the 10 micron line the "positive" ears add to give increased density.

CLAIMS (filed 9 Dec. 1981) 1. A photographic element comprising a support and containing a colour image and a mask therefor which produces edge effects and whereof a first component is a diffusion transfer image formed of a masking dye of neutral or degraded colour and whereof a second component is a sharp retained image formed of said masking dye and of the same sign as said colour image.

2. An element according to claim 1 wherein said colour image is a colour diffusion transfer image and is in the same layer as said first component of the mask, said second component of the mask being in an adjacent layer.

3. An element according to claim 2 wherein the support is transparent and said colour image is a negative.

4. An element according to claim 2 or 3 wherein there is a spacer layer between the layers containing said first and second components of the mask.

5. An element according to any of claims 1 to 4 wherein said masking dye has a density equal to not more than half of the maximum density of said colour image.

6. A method of making a photographic element according to claim 1 containing a colour transfer image which comprises (a) exposing a photographic element comprising a support, at least one lightsensitive silver halide emulsion layer (i) with which is associated a dye-providing compound such that an imagewise distribution of diffusible image dye is formed as a function of development and over said layer (i) a light-sensitive silver halide emulsion layer (ii), (b) developing the exposed silver halide layers, said silver halide layer (ii) being associated with, or (c) being brought into association with, a layer which is on another support and which contains a compound of neutral or degraded colour such that a diffusible dye also of said neutral or degraded colour is formed on said developing, the distribution of which dye is of opposite sign to the distribution of said diffusible image dye, (d) allowing at least some of said diffusible image dye to diffuse into a dyereceiving layer to form said colour transfer image on said other support and (e) allowing at least some of said diffusible dye of neutral or degraded colour to diffuse in register into said receiving layer thus forming also a retained image of said diffusible dye of neutral or degraded colour on said other support and, if necessary, (f) removing developed silver from the silver halide layer (ii).

7. A method according to claim 6 which is carried out by spreading a developer between silver halide layer (ii) and the outermost layer on said other support.

8. A method according to claim 7 in which said outermost layer contains said compound of neutral or degraded colour.

9. A method of making a photographic element according to claim 1 containing a colour-developed image which comprises (a) exposing a photographic element comprising a support, at least one lightsensitive silver halide emulsion layer (i) with which is associated a colour coupler such that an imagewise distribution of non-diffusible image dye is formed on development thus forming said colour image, a light-sensitive silver halide emulsion layer (ii) with which is associated a compound of neutral

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. Hardeners BGE butanediol diglycidyl ether. BVSME bis(vinyl sulphonyl methyl) ether. HCHO formaldehyde. Developer ETA 1 - phenyl - 4 - hydroxymethyl - 4 methyl - 3 - pyrazolididone. It was found that both the elements A and B were soft and had to be prehardened before use. This was done by soaking the coatings in the C41 'Kodacolor' prehardener for 3K at 704 followed by washing and drying; normally this procedure would not be necessary. The donor coating (represented by layer C in Fig.

1) was a coating of a silver chlorobromide emulsion (35% Br, 65% Cl 0.3cm), in gel (Ag 4.0 glum,, gel 4.8 g/m2) overcoated with a supercoat of gel (1 g/m2).

Emulsion and supercoatwere coated on 0.006 inch 'Estar' backed with a dyed pelloid layer. The emulsion was ortho-sensitized for ease of handling.

Process The following developer was used: KOH 56.0 g 5-methylbenzotriazole 3.0 g KBr 2.0 g 11-aminoundecanoic acid 2.0 g ETA 8.0g Waterto 1000 ml HEC (Hydroxyethyl cellulose) 28 g The undercut roller method of processing was used.

The donor coating was exposed to a knife edge placed across a normal silver sensitometric wedge.

Care was taken to ensure good contact between the donor emulsion and the knife edge during exposure.

The exposed coating was then laminated to a prehardened sheet of receiver A using the developer and a 0.002 inch undercut roller. Development was allowed to proceed for 20 minutes at 70 F followed by peel apart. The donor was washed, fixed, washed and then dried, while the mordant was spray rinsed to remove developer and dried. A microdensitometertrace was made across the edge (DmaxtO Dmin) of both the silver image on the donor and dye image on the mordant, and is shown in Fig. 3 of the accompanying drawings. The silver image showed a pronounced edge effect. The dye image showed the symmetrical double ears shown in Fig. 2.

Example 3 The donor coating was exposed to 1000, 100 and 10 micron X-ray lines. The exposed coating was then laminated to a prehardened sheet of receiver B. A 0.003 inch undercut roller was used and development and subsequent treatment was carried out as described in Example 1. The microdensitometer traces of the silver and dye images are shown in Figs. 4, 5 of the accompanying drawings. The silver image (Fig. 4) showed marked conventional edge effects, while the dye image (Fig. 5) showed the symmetrical "double ears" for the 1000 micron line.

For the 10 micron line the "positive" ears add to give increased density.

CLAIMS (filed 9 Dec. 1981) 1. A photographic element comprising a support and containing a colour image and a mask therefor which produces edge effects and whereof a first component is a diffusion transfer image formed of a masking dye of neutral or degraded colour and whereof a second component is a sharp retained image formed of said masking dye and of the same sign as said colour image.

2. An element according to claim 1 wherein said colour image is a colour diffusion transfer image and is in the same layer as said first component of the mask, said second component of the mask being in an adjacent layer.

3. An element according to claim 2 wherein the support is transparent and said colour image is a negative.

4. An element according to claim 2 or 3 wherein there is a spacer layer between the layers containing said first and second components of the mask.

5. An element according to any of claims 1 to 4 wherein said masking dye has a density equal to not more than half of the maximum density of said colour image.

6. A method of making a photographic element according to claim 1 containing a colour transfer image which comprises (a) exposing a photographic element comprising a support, at least one lightsensitive silver halide emulsion layer (i) with which is associated a dye-providing compound such that an imagewise distribution of diffusible image dye is formed as a function of development and over said layer (i) a light-sensitive silver halide emulsion layer (ii), (b) developing the exposed silver halide layers, said silver halide layer (ii) being associated with, or (c) being brought into association with, a layer which is on another support and which contains a compound of neutral or degraded colour such that a diffusible dye also of said neutral or degraded colour is formed on said developing, the distribution of which dye is of opposite sign to the distribution of said diffusible image dye, (d) allowing at least some of said diffusible image dye to diffuse into a dyereceiving layer to form said colour transfer image on said other support and (e) allowing at least some of said diffusible dye of neutral or degraded colour to diffuse in register into said receiving layer thus forming also a retained image of said diffusible dye of neutral or degraded colour on said other support and, if necessary, (f) removing developed silver from the silver halide layer (ii).

7. A method according to claim 6 which is carried out by spreading a developer between silver halide layer (ii) and the outermost layer on said other support.

8. A method according to claim 7 in which said outermost layer contains said compound of neutral or degraded colour.

9. A method of making a photographic element according to claim 1 containing a colour-developed image which comprises (a) exposing a photographic element comprising a support, at least one lightsensitive silver halide emulsion layer (i) with which is associated a colour coupler such that an imagewise distribution of non-diffusible image dye is formed on development thus forming said colour image, a light-sensitive silver halide emulsion layer (ii) with which is associated a compound of neutral or degraded colour such that a diffusible dye also of said neutral or degraded colour is formed on development, the distribution of which is of opposite sign to the distribution of said non-diffusible dye, and (iii) a dye-receiving layer, (b) developing the exposed element, (c) allowing at least some of said diffusible dye of neutral or degraded colour to diffuse into said receiving layer and thus also to form a retained image of said neutral dye or dye of degraded colour and (d) removing developed silver.

10. A method according to any of claims 6 to 9 in which at least three light-sensitive silver halide layers (i) are employed sensitive respectively to blue, green and red each associated with a dye-providing compound such that on development a three-colour image is formed and in which layer (ii) is a pansensitive silver halide emulsion layer.

11. A method according to any of claims 6 to 10 in which there is a scavenger for oxidised silver halide developer between light-sensitive emulsion layer (ii) and light-sensitive emulsion layer(s) (i).

12. A photographic element which has been produced by a method according to any of claims 5 to 11.

13. An element according to claim 2 substantially as described in Examples 1 and 2 herein with reference to Receiver A or B.

14. A method according to claim 6 substantially as described in Examples 1 and 2 herein.

15. A photosensitive element as defined in claim 6,8,9,10or11.

16. A photosensitive element according to claim 15 substantially as described in Examples 1 and 2 with reference to Fig. 1.