JPS5848897B2 - Kanzai Yakido Hanteihou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the degree of printing of a photosensitive material, and more particularly to a method for determining the exposure time of a printing photosensitive plate used in offset printing etc. more clearly than conventional methods.

Conventionally, to adjust the degree of baking, for example, the Kodak Step Tablet Arashi 3 is printed in close contact with the PS plate, and with a negative type, the 0.90 density part of the sixth step from the lightest density side of the Step Tablet is printed on the black plate. I was exposing it to light so that it would be crushed.

This method of determining exposure is not very clear and cannot express subtle differences.

For example, if you print a column that is not completely flattened on the plate, it may turn out to be flattened, and when it is reproduced over a long density range, it is difficult to judge where the solidity starts. The deciding point was that it was difficult to determine the appropriate exposure range.

The present invention eliminates these drawbacks and makes it possible to easily and visually determine the appropriate exposure amount without using special equipment or machines.

The present invention will be described in detail below with reference to the drawings.

First, a black and white transparent parallel line pattern 2 having the same number of screen lines as the image to be printed is prepared.

For example, the black and white ratio of the lines is 1:1 so that it is easy to see when printing.
The one is good.

These line patterns 2 are obtained by bringing a line contact screen and a lithium film into close contact with each other and applying appropriate exposure.

In the same manner, a flat screen pattern (not shown) having a screen area ratio of 50% is created.

Prepare a screen with the same number of lines as the screen to be printed.

These parallel line pattern 2 or flat mesh pattern are used in combination with Kodak Step Tablet 1 to measure the degree of baking.

In use, as shown in FIG. 2, line pattern 2 is placed on PS plate 3, and step tablet 1 is placed on top of it and exposed.

In addition, in order to make three types of step tablet 1 only, step tablet 1 and line pattern 2, and line pattern 2 only, step tablet 1 and line pattern are printed as shown in Figures 1 and 2. 2 are placed slightly apart.

The direction of the lines in the line pattern 2 and the longitudinal force direction of the step tablet 1 may be parallel or perpendicular to each other.

The prepared line pattern 2 and step tablet 1 are arranged as described above and printed on the PS plate.

In the conventional method, for a negative PS plate, the optimum exposure condition is when the step tablet with a density of 0 and 90 is flattened, but it is difficult to judge from which step the step becomes solid.

However, when printing Line Pattern 2 and Step Tablet 1 together, if the exposure amount is lower than the optimum exposure condition on a negative PS plate, the image part of the line pattern becomes thinner at the density level of 0.90. If the exposure conditions are higher than the optimum exposure conditions, the edges of black and white pattern images will be reproduced sharply.

This makes it clear how to determine optimal exposure conditions, which was previously unclear.

So far, we have talked about setting exposure conditions for halftone printing, but the same can be said for line drawings, characters, etc.

Among the line drawings to be reproduced, a line pattern with the same line width as the minimum line width is selected and printed overlappingly.

In the case of a negative type, if the density is 0.90 and the same dimension as the minimum line width can be reproduced, the exposure is optimal.

By observing lines under optimal exposure conditions, you can see how well the minimum line width can be reproduced by printing.

Further, if a document contains a certain density range and it is desired to reproduce an image with a certain density or higher, exposure may be applied so that a line corresponding to that density is reproduced in the step tablet.

The method described above can be used not only for offset PS plates but also for photosensitive resin letterpress plates.

Furthermore, it would be wise to implement the same concept for the physical PS version as well.

Example l As a result of exposing the step guide of the present invention in close contact with a Kodak Polymatic Chrysoplate LN (Kodak Company PS plate), the part with only the step tablet was reproduced in six stages, and the halftone part was In many cases, it is not clear where the pattern starts, but in the part where the step tablet and the line pattern overlap, the line pattern is interrupted at the fourth row, and the line is not reproduced at this point, and the line pattern is not reproduced at the third row. It was found that the edges of the line pattern were reproduced sharply.

The PS version is designed so that the 6th step of the Step Tablet with a density of 0.90 is solid, so this printing level is insufficient and if you apply 2.8 times the exposure, you can print the 6th step with a density of 0.90. It was found that the edges of the straight line pattern were reproduced sharply and the exposure was optimal.

Actual case 2 When exposure was carried out with the step guide of the present invention in close contact with Fuji Plano Super Negative Grain Coat, which is a PS plate manufactured by Fuji Photo Film Co., Ltd., the density was lower in the 5th and 4th rows in part 6, which only has step tablets. There is a difference, and when I printed it, I wasn't sure if it would be flattened from the 5th level or flattened from the 4th level, and I didn't know how much to increase the exposure to get the optimal exposure, but the step tablet and line pattern overlapped. In part 5, in the sixth row with a density of 0.90, the parallel line pattern was visible, but it was thinner and underexposed, and in the fifth row, the edges of the parallel line pattern were reproduced sharply.

Therefore, it was found that if the exposure was applied an additional 1.4 times, the lines would be reproduced like this in the 6th row.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a step guide of the present invention that combines a step tablet 1 and a parallel line pattern 2, and FIG.
A cross-sectional view at AA when the step guide shown in the figure is placed on a PS plate, and Fig. 3 is a reproduced image of the step guide exposed and developed on the plate material. 1... Step tablet, 2... Line pattern, 3... Photosensitive plate material for printing.

Claims (1)

[Claims] 1. A black and white line pattern with the same number of screen lines as the halftone image to be printed, or a flat screen pattern with a halftone area ratio of 50%, or a line pattern and step tablet with the same line width as the minimum line width in the line image to be printed. A method for determining the degree of printing of a photosensitive material, in which it is layered on a photosensitive printing plate material and exposed to light.