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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/28—Silver dye bleach processes; Materials therefor; Preparing or processing such materials
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F3/00—Colour separation; Correction of tonal value
  • G03F3/10—Checking the colour or tonal value of separation negatives or positives
  • G03F3/107—Checking the colour or tonal value of separation negatives or positives using silver halide photosensitive materials

Definitions

• a process for copying colored images for the production of photographic colored positive images for surfaceviewing is provided.
• This process also called color proofing, allows rapid recognition of the matching which the final printed product will show in the printing industry, especially in the manufacture of multi-color intaglio-printed products.
• the positive component color separations and the black separations of the original are projected onto a light-sensitive positively acting colorphotographic material containing silver halide.
• the black separations are not used during the whole time of exposure.
• the amount of light of the exposure of a color separation without and with the black separation is in a ratio of 1:19 to 1:1.
• the present invention relates to a process for copying coloured images for the production of photographic coloured positive images for surface-viewing which in the printing industry allow rapid recognition of the matching which the final printed product will show.
• a process has now been developed which does not have all these disadvantages and which leads to images which very closely approach the intaglio-printed product, espeprojected with light onto a light-sensitive positively working colour-photographic material containing silver halide, wherein the component colour separations corresponding to the individual colours are successively projected onto the light-sensitive colour-photographic material using the light of the corresponding colour, in each case once without and once together with the black separation, the amount of light in the exposure with and without the black separation being in a ratio of 1:19 to 1:1, preferably 1:9 to 1:1, and the exposed material is developed to give a positive image for surface-viewing.
• the process according to the invention is primarily suitable for simulating multi-colour intaglio-printed products.
• Photographic material for the silver dye bleaching process has proved particularly advantageous for the process according to the invention, since colour images can be produced therewith in which the colours correspond relatively well with the printing inks in colorimetric respects.
• a further advantage'of the photographic material for the silver dye bleaching process consists of the fact that positive copies of positive separations can easily be produced therewith.
• the present process is however not restricted to photographic material for the silver dye bleaching process and material which is for example used for the colour development process is also suitable, even if less successfully.
• a suitable colour-photographic copying material for the silver dye bleaching process advantageously has a silver halide emulsion layer on an opaque support, sensitised to red light and dyed with a bleachable cyan dyestuff; a silver halide emulsion layer sensitised to green light and dyed with a bleachable magenta dyestuff; optionally, a
• the component 'colour separations required for the process according to the invention for example a green, red and blue filter separation, and the black separation are produced in the usual and known manner. Since these component separations are in the form of monochrome and indeed generally black and white images, one only remains dependent on the spectral sensitivities of the copying material in choosing the copying lights for the further photographic processing. I i
• the component colour separation positives which are thus mostly black and white, in other respects correspond ,to the continuous positives used in the half-tone intaglio printing technique.
• these positives are contact copies or enlargements of separation negatives which have been produced by means of colour filters, either conven- .tionally or via. a so-called scanner.
• the contrast range that is to say the difierence between maximum and minimum density, of the colour separation positives, is as a rule adapted to the requirements of the individual printing works and is generally within the limits of 1.2 and 1.7.
• a black separation is also produced so as to improve the reproduction of the neutral grey a'fid 'black.
• the density and ,character of the black separation also vary from factory I to factory.-Depending on requirements, the black positive is for example produced as a skeleton of relatively high contrast or as a half-tone copy with good depiction in the middle shades.
• the total proportion of the printed maximum density attributable to the black separation also dilfers. As a rule it is between and 30%, but can incliease up to 100% using special techniques in grey and b ack.
• the process according to the invention is carried out in such a manner that, depending on the density and range of the black separation, the latter is co-exposed to a greater or lesser extent together with the colour separations, this being done in such a way that the proportion of the exposure of the black separation together with the colour separation amounts to 50 to 90% of the total exposure.
• a total of 6 component exposures is thus dealt with, proportion of the exposure together with the black separation relative to the total exposure being capable of variation within the specified liimts, depending on the subject and on the image character.
• the sub-division of the exposure looks as follows:
• the copying light in each case does not have to be monochromatic in the strict sense. This is because particularly good images resembling the mechanically printed product'are obtained when the light used extends into regions where the sensitizations of the individual layers overlap, or when the separations are copied with certain proportions of wrong light.
• black component does not haveto be the same for all three colour exposures. In some cases better results are obtained when twoor three diifer'entblack components are used.
• the light-sensitive positively working colour-photographic material containing silver halide which has been exposed in accordance with the process of the invention may be developedin a usual and known manner.
• the silver is first developed, the dyestulfs are then bleached in the areas where there is metallic silver, and finally the excess silveris removed.
• a colour image is obtainedin all cases which comes close to the mechanically printed product which can be obtained from the same separation positives.
• Circumstances can, particularly in cases of wide differences between the colours, be such .that this general rule is no longer valid. Since however, every printing works uses a very particular separation characteristics, the correct black component in the colour copy must once be empirically determined with accuracy. The exposure ratios thus determined are then valid for the particular works as long as the character of the colour separations is not changed.
• Another way of determining the correct black component consists of first setting up so-called nomograms. Insofar as the density range of the black separation and of the individual colour separations is then known, the exposure component of the black separation in combination with the colour separation can be read off from-the nomogram. A particular nomogram is always only .pre-
• the exposure component of -the blackcolour separation combination can be calculated as follows:
• EXAMPLE 1 The separation positives of a coloured original image are copied in the following manner onto a photographic material for the silver dye bleaching process which contains a red-sensitised, green-sensitised and blue-sensitised layer: a
• the blue separation B- is combined with the black separation S and projected through a blue filter.
• the black separation is then removed and the blue separation by itself is again projected.
• the exposure times are so chosen that the two exposures B-l-S and 3 give the correct density scale and shade value scale on the photographic material.
• the same procedure is repeated with the green separation and the red separation, using the corresponding green and red filters respectively.
• the empirically determined black component is thus 75%.
• the colour copy thus obtained comes very close to the printed products made with the same separations, particularly as regards the neutral grey shades produced by the three colour separations.
• the empirically determined black component is thus 67%.
• the colour copy thus obtained comes very close to the printed products made with the same separations, especially as regards the neutral grey shades produced by the three colour separations.
• the black component is not the same in all three colour exposures because in order to achieve better results it is often advantageous to use two or three diiferent black components.
• the empirically determined black components are here 85%, 89% and 79%.
• the colour copy thus obtained comes very close to the printed product obtained with the same separations, particularly as regards the neutral grey shades produced by the three colour separations.
• EXAMPLE 5 Separation positives of an original colour image are copied onto a positively working photographic material for the silver dye bleaching process in the same way as described in Example 1.
• A Axis for the density range of the black separation
• B Axis for the density range of the color separation
• C Proportion of the exposure time for black-colour separation combination in percent.
• the colour copy thus obtained comes very close to the printed product made with the same separations, especially as regards the neutral grey shades produced by the three colour separations.
• EXAMPLE 7 Separation positives of an original colour image are copied onto a positively working photographic material for the chromogenic colour development process in the same way as described in Example 1.
• the black component was determined as 85% for the blue separation with the aid of the same nomogram as specified in Example 5, and was for simplicity also used for the red and green separation.
• a process for the production of a photographic copy which simulates a multi-colour print in which the positive component colour separations and the positive black separation of the original are projected onto a light' sensitive positively acting colour-photographic material containing silver halide, wherein the component colour separations corresponding to the individual colours are projected successively onto the light-sensitive colour-photographic material using the light of the corresponding colour, in each case once without and once together with the black separation, the amount of light of the exposure without and together With the black separation being in a ratio of 1:19 to 1:1, and the exposed material is developed to give a positive image for surface viewing.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=4394389

Family Applications (1)

Country Status (7)

Cited By (7)

Families Citing this family (3)

• 1968
  • 1968-09-12 CH CH1367468A patent/CH501250A/de not_active IP Right Cessation
• 1969
  • 1969-08-21 DE DE19691942682 patent/DE1942682A1/de active Pending
  • 1969-09-05 FR FR6930327A patent/FR2017876A1/fr not_active Withdrawn
  • 1969-09-08 US US856152A patent/US3576627A/en not_active Expired - Lifetime
  • 1969-09-10 GB GB44658/69A patent/GB1267823A/en not_active Expired
  • 1969-09-11 NL NL6913872A patent/NL6913872A/xx unknown
  • 1969-09-11 BE BE738755D patent/BE738755A/xx not_active Expired

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