We applied the Kodak 2-Mask-Method to the Color transparencies, using the three kinds of the home-made sensitive materials and a Kodak Tri-X Type-B plate.
As for the color separation filters, Wratten's #33, #29, #47B and #58 were used in order to examine the relation between the developing time and γ which would be able to make the minimum Density of Mask and color separation negatives 0.4, and the Density Range of color separation negatives 1.2. We get each curve of special quality through each filter and made up γ-Developing time curve, by means of which, we got the proper Exposure time and put it into practice. In consequence we found that, so long as we did according to the Kodak's data, the plate of A company was the best.

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In high-speed wet printing, a piling-up of the three colors in the same area has to be avoided, and a special black printer must be required. A much heavier black printer is then substituted for combination of the three colored inks, and it is necessary to compensate for this by reducing the amount of the three colored inks which print in neutral areas. A method called “U. C. R. masking” is used for this purpose.
We have applied this to the reproduction of a color transparency having much shadowy detail, and found it very effective one. It makes printing more easy, more speedy and more economical. Moreover the detail of shadow is much better than usual one.

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Examining to make halftone-separation-positive from the color negative film using masking method without hand retouching, we had good results.
Used color negative films were “Ektacolor”, “Agfacolor negative”, “Fujicolor negative” and “Konicolor negative”. And we took the 1-stage masking method for the higher contrast film and the 2-stage method for lower contrast one, and the color correction masks were developed in a coupling developer which formed a magenta dye for yellow, magenta plates and blue dye for cyan plates.
Screening was done with the gray contact screen through the camera using a fluoresent light source. As a guide of tone and color reproductions, we used the gray and color scales.
Consequently, the tone-reproduction curve was not linear but it had a toe and a shoulder, and the shape of this curve was very important. The printings showed excellent results in those sharpness and were rich in details. However it seems to have some problems on the color reproduction.

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Examining the tone reproduction of deep-etch plates used gum arabic, polyvinyl alcohol and fish glue coating solution, we found that gum arabic plate was the best.
In this experiments we examined the tone reproduction represented with dots area, resolving power and sharpness of the image.
The microphotographic pictures were taken in order to compare with the original. As for loss of the tone, halftone dots in gum arabic plate, PVA plate and fish glue plate, we witnessed them 1.2%, 3.6% and 6.7% respectively.

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The condensation products of p-aminodiphenylamine diazosulphate and p-formaldehyde are used to produce sensitive coating film of presenstitized plate for lithography. The stability of this sensitive film is governed by the supporter.
On zinc plate, it will take place dark reaction at about 10°C within 24 hours but on aluminum plate within three days. When these metal plates are treated with the solution of sodium silicate, the coating films on the metal surfaces are stabilized and those lives are prolonged.
Even by this treatment, the coating film on zinc plate can be kept satisfactorily at about 10°C for only three days and on aluminum plate for seven days.
We found that the sensitive diazonium salts on the aluminum plate with alumite surface was very stable and the coating film could be preserved for eighty days without any change.

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After making a series of tests by reverse reflectance method to appraise penetration of printing ink, vehicle and color paste into various stocks, the authors have obtained satisfactory results.
In these tests, penetration is determined by evaluating reduction in reverse reflectance for ten minutes for a coated paper and five minutes for an uncoated paper. Under the testing conditions of temperature 20°C±1°C and relative humidity 60%±5%, penetration of a vehicle into a commercially available paper showed the maximum deviation of 4% (after 5 times repetition), and that of paste into a similar paper showed the maximum deviation of 30% (after 5 times repetition); indicating thus, this process is generally useful for penetration tests.

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In roller setting of printing machine, the roller pressure is adjusted by using the “Koban” (a kind of thickness gauge) or the friction of a paper piece. This can be set with fair accuracy through experiences only when conditions were constant. It is difficult that proper roller pressure is maintained with being human errors in various conditions
By adjusting, with some measure more superior to the above way roller pressure, the uniform printing shall be obtained. In place of the “Koban” or the paper piece being put between a plate cylinder (or a distributing cylinder) and rubber rollers (or damping rollers), our designed tool is measuring the tightness with steel sheet (a tongue plate of 8/1000 inch thickness) being inserted in and drawn out.
Chiefly this measurement is applied to the newspaper rotarypress. As for direction of the “Rollor Gauge” being drawn out, we did towards the direction of considering it the maximum contact and minimum contact (tangent direction) about two rollers consisted with a forme roller (6 inch φ) and an ink distributing roller (4.5 inch φ), and measured, when a plate cylinder or a distributing cylinder fixed on direction of the axis at 5 points (A-E) around the circumferences on 3 parts-left (G), right (P) and middle (M) of them.

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Surface measuring method by electric capacitance being considered most rational to evaluate the lithographic grain, theoretically, we practised this method on measuring many manifoldly grained surfaces and examined the possible effects of the method.
Facility of the procedure, scarcity of personal errors and good consistency of the method certify the advantage of the method over the Stylus-type surface measuring method and others.

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In this experiment, a new method for determining the thickness of chromium coatings on copper, iron, brass and type alloy printing plates with the micro vickers hardness tester has been studied.
The new method may be summarily explained as follows:
(1) At first, several tests of vickers hardness on the specimen are made under various loads from 25 to 1, 000g. The data thus obtained are plotted on a log-log co-ordinate, in which the ordinate represents hardness, H_v, and the abscissa, depth of indentation, h. Two straight lines connecting the plotts in the co-ordinate are drawn, and a point b is obtained as the intersection of these two lines. Letting the value on the abscissa (i.e., depth of indentation) of this point b equal h_b thickness of the chromium coating of the specimen can be calculated by the formula, t=Kh_b, where K is the coefficient. (Fig. 4, above and Fig. 6)
(2) In the above case, if the horizontal straight line (i.e., the hardness line of chromium coating) is predetermined, the point b can be obtained by merely determining the inclined straight line (i.e., mean hardness line of chromium coating and basic metal) by plotting two or more hardness tests. However, the value of hardness H_m to be tested in this case must be chosen within the limits H_p>H_m>1.5H_b where H_p and H_b represent the hardness of plated and basic metals respectively. (Fig. 4 below)
(3) The coefficient K in the formula, t=Kh_b, varies with the hardness ratio of plated and basic metals, H_p/H_b, as shown in Table 1 and Table 2, However, the coefficient K has a value of about 9 for the specimen which H_p/H_b is more than 5, as chromium coatings on copper, brass, iron and type alloy.
(4) The new method was applied to the determination of the thickness of the chromium coating on gravure cylinder plates and stereotypes, which revealed that the values obtained by this method were almost identical with those by careful micrographic measurement of the section. (Table 3)

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