634 HANDBOOK OF PHOTOGRAPHY 



For a -io-oz. total solution a suitable compounding would be 



/"Water 34J'2' oz. 



M3< Stock solution A 7 oz. 



(stock solution BB 3J.2 oz. 



Use 15 OZ. for each tissue. 



It is not advisable to decrease the quantity of solution below 15 oz. for each tissue. 



It is a well-known fact that the color contrast of a blue pigment (spectral reflecting 

 power) is much less than that of a magenta and yellow pigment. 



This difficulty is greatly accentuated when copying a color print. The Eastman 

 Kodak Co. has lately advocated an automatic masking method in making paper 

 prints from original Kodachrome slides. But even when working from color-sepa- 

 ration negatives made directly from the original subject a vast improvement in 

 general color balance can be secured by chemically reducing the contrast of the 

 magenta and yellow tissues with respect to the blue. This procedure, however, 

 necessitates considerable increase in the exposure of the bromides for the magenta 

 and yellow tissues and a subsequently longer immersion in the carbro solution. 



It is necessarj^ to emphasize strongly at this time that the color contrast of the 

 tissues and the exposure of the bromides, although related to one another, are two 

 entirely different things. For instance if the three tissues are processed in strictly 

 identical manner and the bromides are so exposed as to give correct balance in the high 

 lights, then the shadows will tend toward orange. If now the contrast of the magenta 

 and yellow tissue is decreased to match the contrast of the blue without any change in 

 the exposure of the magenta and yellow bromide, the result will be a preponderance 

 of blue both in the high lights and in the shadows. 



With a correct set of negatives developed to gamma of unity and printed on an 

 Illingworth de luxe bromide paper, normal grade, and developed in Amidol, correct 

 color contrast will be obtained by sensitizing the blue tissue for 45 sec, the magenta for 

 1^2 min., and the yellow for 1 1<4 min. in the Type II single-bath method just described. 

 This applies equally well to M2 and M3 formulas. 



With the above treatment of the tissues it will be necessary- to expose the bromide 

 for the magenta tissue 1.6 times and the bromide for the yellow tissue 1.2 times the 

 exposure of the bromide for the blue tissue. 



A slight variation in this factor might be foimd necessarj^ with different stocks of 

 tissue. The above figures, however, will be found sufficiently accurate to start with. 



This is the factor appearing in column 5 of Table II. 



As the carbon tissues are removed from the carbro solution, they must be brought 

 into intimate contact with the corresponding bromide. It is necessarj' that each 

 soaked bromide be held in readiness by placing it face up on a piece of plate glass and 

 covered with an even pool of water. At the expiration of the time of sensitizing, the 

 tissue is withdrawn and, without draining, brought down face to face on the bromide. 

 The thin pool of water prevents intimate contact and allows time for squeegeeing. 

 The tissue and bromide are held together by steady pressure with the left-hand fingers 

 along the safe edge at the extreme left, and a flat rubber squeegee held with the right 

 hand moved across the sandwich from left to right with a steady, gentle, but quite firm 

 stroke. The next stroke of the squeegee is taken in the opposite direction by holding 

 it with the left hand and holding down the tissue and bromide with the fingers of the 

 right hand along the safe edge at the extreme right. 



Four strokes of the squeegee, two in each direction, will be foimd ample. 



It is extremely important to avoid any movement of the tissue when once in con- 

 tact with the bromide as the chemical action begins at once and any movement would 

 give rise to a double image and spoil the results. 



