DE2136064A1 - Process for the production of a screened, photographic color copy simulating a multicolor print - Google Patents

Description

Case TEL

Attorney's file 21 2o5 July 19, 1971

Process for the production of a screened, photographic color copy simulating a multicolor print.

The present invention relates to a method for the production of screened colored positive reflective images, which in the printing industry rapidly

BATH ORIGINAL 109885/1328

'Let the mood of the partial print positives recognize, which that final print product will have. The color tones of the primary colors yellow, purple and blue-green become through the copying process controlled so that they are adapted to the printing colors *

Even today, printing a photolithography is a time-consuming and costly affair. Different Attempts have been made to switch to faster and cheaper way proofs with color and tonal value correct to the exclusion of the usual pressure path. So far, however, the methods have been too laborious, or the ' Results are not satisfactory. .

Particular problems arise in the production of so-called "color proofs" on photographic multicolor material, because in the graphics industry, a "proofing system" is required to be able to vary the Basic shades and color densities.

A method has now been found that meets this requirement fulfills and leads to images that are very appealing to the printed product to come close.

The invention accordingly provides a method for producing a multicolor print, preferably Simulating, screened, 'photographic' offset printing Color copy, in which the screened positive partial color separations assigned to the individual colors of the

10 9 8 8 5/1328 ^ßAD ORIGINAL

3 2V3606A

Template together with the rastered black extract and, if applicable in addition, the black separation alone is exposed on a light-sensitive, positive working., color photographic material are characterized in that

(a) at least one of the partial color separations with

(b) the black extract and

(c) at least partially with at least one of the others Partial color separations

exposed to the light-sensitive color photographic material with the light of the color assigned to the partial color separation (a) and the material exposed in this way is processed into a screened, positive reflective image, which has basic colors matched to the printing inks.

In the method according to the invention, one proceeds in such a way that the screened positive partial color separations are used the original (blue = B, green = G, red = R) and the black separation (black = S) brings the template as combinations BS, GS and RS into congruence with one another, and then one after the other in any order with the associated filters (blue = b, green = g, red = r) onto a light-sensitive, positive working photographic material in the combinations BS-b, GS-g, RS-r and optionally also S alone exposed, with the improved adaptation of the color impression the color copy to the printing inks is achieved by adding at least one of the following combinations exposed: BGS-b, BGS-g, BRS-b, BRS-r, GRS-g, GRS-r, BGRS-b, BGRS-g or BGRS-r.

BATH ORIGINAL

109885/1328

The exposures, with and without a 2nd and possibly J. partial color separation (ο), are based on the densitometric Measurement of the printing color and the colors on the photographic copy calculated.

In the method according to the invention, the procedure is such that, depending on the measured color deviation of the individual primary colors of the "color" proof "to the printing ink, a second and optionally third partial color raster positive is exposed to a greater or lesser extent with the partial color positive to be copied, namely in such a way that the The proportion of exposure of the additional second or third partial color separation with the main color separation together is generally 10 to 100 %, preferably 40 to 80 %, of the total exposure time of the first partial color separation.

The second possibility to adapt the "proof" to the printing conditions is besides the variation of the color tones the setting of the maximum densities of the individual basic colors, or reduction to the printing color density. To this The purpose is an exposure with the complementary color filter to the reducing color through the black print positive made. The exposed material is then developed into a positive reflective image.

The method according to the invention is primarily suitable Line for simulating screened multi-color offset printing products.

BATH ORIGINAL 109885/1328

For the method according to the invention, photographic has proven Material for the silver dye bleaching process proved to be particularly advantageous because it produces color images in which the colors are proportionate to the printing inks correspond well. Another advantage of the photographic material for the silver dye bleaching process is that it enables positive copies of positive separations to be made with ease. That_ However, the present process is not limited to photographic material for the silver dye bleaching process, either Material used e.g. for the color development process is suitable.

The partial color separations required for the method according to the invention, e.g. green, red and blue filter separations, as well as the black extract are more common and well known Way made. Since these partial excerpts are available as monochrome and generally as black and white slides, one is in the photographic processing in the The copying lights only depend on the spectral sensitivities of the copying material.

The mostly black and white partial color separation positives correspond to those usually used in raster offset printing technology used positives. These grid positives are usually contact copies or enlargements of gridded ones or halftone separation negatives, with halftone negatives a contact grid must also be copied. The halftone

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or halftone negatives are ENTV with color filters manufactured ^r Eder conventionally or via so-called "scanner". The "retouching and correction of the color separations" is coordinated with the color scale of the individual printing works.

BATH ORIGINAL

109885/1328

example 1

If a warmer (more yellow) purple ink is used, so you can adjust the "color proof" of the printing color, 'by the proportion of yellow in the purple is increased. The way it works is as follows:

Partial exposure ($ 40) 1. Blue filter positive Black print positive Partial exposure (60 #) 2. Blue filter positive Black / print positive H-green filter positive

Green filter positive Black print positive

Entire blue exposure

entire green exposure

4th Red filter positive
Black print positive entire
Red
exposure

Effective relative exposure times:

1. 1.6 seconds

2. 2, 3/4 seconds

1 098 ^ ^{5/1 3 2 e SGleunden}

4. 2 seconds

EAD ORIGINAL

The blue filter positive becomes register with the black print positive precisely combined and copied onto the blue-sensitive emulsion in a partial exposure to blue light the green filter positive was added and the second partial exposure was exposed to blue light. For the green filter exposure the green filter positive and the black print positive are used and the red filter positive is used for the red exposure also again with the black print positive.

After these exposures it becomes color photography Material developed into a positive reflective image similar to that of the same using the silver dye bleaching process Print product produced excerpts comes close.

For comparison, a densitometer is used to measure the printing ink with the photographic "color proof" with and without admixture of a 2nd or 5 · partial color separation measured. The following values result:

109886/1328 _BAD0R1GINAL

213606A

Measuring filter Relative densities purple blue
green Printing color in the densito
meter yellow 0.14
1.55
0.57 0.02
0.26
1.45 without admixture blue
I green
Red 1.32
0.85
0.20 0.18
1.40
0.58 0.02
0.30
1.45 with admixture of green
filter negative with
$ 60 the blue filter
negative bluish tinge
tion blue
II green
Red 1.31
0.56
0.28 0.18
1.50
0.58 0.02
0.31
1.45 blue
III green
Red 1.31
0.82
0.28

Explanation:

The printing inks used are measured here.

II These are measured values of a "color proof" without admixture.

III Here the selected division of the blue exposure into a partial exposure with blue filter positive + black print positive and a $ 60 partial exposure with blue filter positive + black print positive + green filter positive with unchanged exposure of the combinations green filter positive + black print positive and red filter positive + black print positive is shown. The exposure times are calculated as follows: The blue exposure with the blue filter positive and the black print positive is K seconds for a correctly exposed image. This exposure is now divided into a partial exposure of 1.6 seconds (4θ #) for blue filter and black print positive and 2. K seconds

for the second partial exposure of the blue filter, green filter and black print positives.

109885/1328 _BAD original

- ίο -

example

If warmer purple and blue-green printing inks are used, the working method for adapting the "Color-Proof" is the following:

Partial exposure blue filter positive black print positive

Partial exposure blue filter positive black print positive + green filter positive + Red filter positive

Green filter positive Black print positive

entire
Green exposure

4th Red filter positive
Black print positive entire.
Red
exposure

Geeanite "

fceJ ic.'i-

tion

Effective relative exposure times:

109885/1328

1. I ₃ 6th Seconds 2. 2, 4th Seconds 5. 4th Seconds 4th 4th Seconds BAD ORf ¹ QSNAL

2Ϊ36064

As in Example 1, there are 2 exposures on a photographic material for the silver color bleaching process with the blue filter:

The first with the blue filter and black pressure positive, the second exposure additionally with green and red filter positive. The green and red exposure remain the same as in Example 1. After the exposures, a positive "top-view image" is obtained, similar to that produced with the same separations Print product comes close.

Relative density values, same as measured in example 1:

Measuring filter Relative densities purple "blue- Printing color in the densito 0.14 green meter yellow 1.55 0.02 with subdivision of the bluish tinge
tung: blue 1.32 0.58 0.26 40 $ part seal with blue
filter positive + black print
positive green 0.85 0.18 1.45 60 ^ ige partial exposure with blue
filter positive + green filter positive
tiv + Schwarzdruökpositiv. Red 0.37 1.50 0.02 blue 1.31 0.61 0.31 green 0.82 1.48 Red 0.40

BATH ORIGINAL

109885/1328

The blue exposure is again divided into exposure for the first partial exposure of blue filter and black print positive and 60% exposure for the second partial exposure, in which blue filter, green filter, red filter and black print positive are used. This mixes yellow with the purple and blue-green color of the "Color-Proof".

Regarding the density values, it should be mentioned that a trained eye can see a difference of approximately 0.03 density units can perceive.

ORIGINAL BATHROOM

109885/1328

Example 3

Instead of the usual blue-green hue, a reddish blue-green is desired, with an additional one the maximum density of the cyan layer must be reduced. The way it works here is as follows:

Blue filter positive \ entire blue \ total
belich
tion 1. Black print positive exposure \ \\ 2. Partial exposure ($ 75)
Green filter positive
Black print positive Total
Green-
exposure 11 '■ Partial exposure (25 ^)
Green filter positive
Black print position Iv
+ Red filter positive (I. Red 4 ". Red filter positive exposure ι Black print positive ¹ Red
exposure 5. Black print positive

Effective exposure times: 1. H- seconds

2. 3 seconds

3. 1 second

4. 4 seconds

'.r: M 5 rf'lirdert the maximum density' of the blue-green

109885/1328

BATH

As described in Example 1, the Separation raster positives of an original color image on a photographic material copied for the silver dye bleaching process.

The exposure times of the partial exposure are based again according to the desired "percentage admixture" one basic color to the other basic color. Likewise, the exposure for the reduction of the cyan density is of the desired change · dependent.

With these exposures, a positive reflective image is obtained, similar to that produced with the same separations Print product comes close.

BAD ORIGfNAL

9885/1328

Claims (1)

2 ^ 36064 Claims 1. A process for the production of a rasterized, photographic color copy simulating a multicolor print, in which the positive, rastered partial color separations of the original assigned to the individual colors together with the rasterized black separation and additionally, if necessary, the black separation alone on a light-sensitive, positive working, Color photographic material are exposed, characterized in that a) at least one of the partial color separations with b) the black extract and c) at least partially with at least one of the other partial color separations exposed to the light-sensitive color photographic material with the light of the color assigned to the partial color separation a) and the material exposed in this way is processed into a screened, positive reflective image, which has basic colors matched to the printing inks. 2. The method according to claim 1, characterized in that the second part color separation c) during 10 to "100 $ the Total exposure time of the partial color separation a) is also exposed. BATH ORIGINAL 109885/1328 5. _ The method according to claim 2, characterized in that that the second partial color separation c) during 40 to 8o ^> the total exposure time of the partial color separation a) is also exposed. 4. The method according to any one of claims 1 to J>, characterized in that a "photographic material for the silver dye bleaching process is used as the color photographic material. 5. Method according to one of Claims 1 to K _3, characterized in that the photographic color copy is used to simulate a multi-color flat printing product. . BATH ORIGINAL 109885/1328