However, because the areas for color tints usually are irregular in shape and require more skill in applying them, the cost of color tinting may be greater than the cost of the halftones.

One definite problem arose regarding the use of the color "green." As shown opposite, green may be secured from a combination of full yellow and full blue. If this "combination" green were used, both blue and yellow color plates and an extra press run would have been necessary, whenever green was wanted. As a result, a green ink was used instead of the "combination" green in some chapters.

The subject "Color and Its Use" is discussed on pages 423 to 428.

DS-25

DT-60

Transograph Corporation, New York City.

Shading Film.

1. A transparent film on which cross-hatchings and halftones are printed in ink has been

developed by several firms. This shading film is placed over the original drawing on those sections to be shaded and a photograph is taken of the combination. The halftones available in this film are those used for newspaper work, that is, from a 2S-linc to a 60-line screen. Perhaps in the future, they may also be made with a finer screen. Film is made for light or dark background.

2. A modification of the transparent film is also available in the form of illustration

board, which when treated with a chemical solution brings out the shadings in the desired sections. A screen as fine as 80-line may be secured in this form. This may be secured from The Craftint Manufacturing Company, Cleveland, Ohio.