By weight
I.—Acridin yellow or acridin orange, N. O.  1 part
Alcohol100 parts
Water, distilled400 parts
II.—Congo rubin  1 part
Alcohol100 parts
Water, distilled400 parts
III.—Tetraethyldiamidooxytriphenyl carbinol  1 part
Alcohol100 parts
Water, distilled400 parts

The screen solutions, after being filtered through paper filters into clean dishes, are utilized to bathe 6 clean glass plates previously coated with 2 per cent raw collodion; we require 1 plate for blue violet, 2 plates for red, 2 plates for yellow, and 1 plate for green, which in order to obtain the screens are combined in the following way: Yellow and red plate, yellow and green plate. For special purposes the other red plate may be combined with the blue violet. Another method of preparing the screens is to add the saturated solutions drop by drop to a mixture of Canada balsam and 2 per cent castor oil and cement the glasses together. Those who consider the screens by the first method too transparent, coat the glass plates with a mixture of 2 to 3 per cent raw collodion and 1 per cent color solution. Others prefer gelatin screens, using

By weight
Hard gelatin (Nelson’s)  8 parts
Water100 parts
Absolute alcohol 10 parts
Pigment  1 part

This is poured over the carefully leveled and heated plate after having been filtered through flannel.

The collodion screens are cemented together by moistening the edges with Canada balsam (containing castor oil) and pressing the plates together in a printing frame, sometimes also binding the edges with strips of Japanese paper.

On the evening before the day of work, good dry plates of about 18° to 24° W. are dyed in the following solution:

By weight
Stock solution, No. 1 16 parts
Distilled water100 parts
Alcohol  5 parts
Nitrate of silver (1.500) 50 parts
Ammonia  1–2 parts

This bath sensitizes almost uninterruptedly to line A. The total sensitiveness is high, and the plate develops cleanly and fine. Blue sensitiveness is very much reduced, and the blue screen is used for exposure. As far as the author’s recollection goes, the plate for the yellow color has never been color-sensitized, many operators using the commercial Vogel-Obernetter eosin silver plates made by Perutz, of Munich; others again only use ordinary dry plates with a blue-violet screen. This is, however, a decided mistake, necessitating an immense amount of retouching, as otherwise it produces a green shade on differently colored objects of the print.

For the red color plate the dry plate is dyed in

By weight
Stock solution, No. 2 10 parts
Distilled water100 parts
Nitrate of silver (1.500)100 parts
Ammonia  2 parts