Penrose's Annual: the Process Year Book and Review of the Graphic Arts

Abstract

THis volume fully maintains the reputation the previous members of the series have earned for the editor and publishers. The newest item in it is a description by Mr. Fishenden of the Pantone process, which Mr. Ronald Trist has now so far perfected that he no longer objects to publication of its details. “Planished plates of suitable metal are first coated with an electro deposit of copper to a thickness of, say, five one-thousandths of an inch, and then with a chromium deposit of two ten-thousandths of an inch.” The plate is coated with a solution of fish-glue and bichromate, exposed, washed, and burned-in as usual in photoengraving. It is then treated with hydrochloric acid, which dissolves the chromium where it is exposed, but as it does not attack the underlying copper it cannot etch too deeply. The plate is next dipped into a solution of a silver salt, and then a few drops of mercury are rubbed over it. Amalgamation takes place immediately except in those parts where the chromium surface remains, and the mercury surface repels the ink without the use of water. The plate is now ready for trimming and mounting. The advantages of the process are many. It saves much time, as underlaying, reproving, and fine etching are unnecessary Fresh plates can be prepared as rapidly and cheaply as electros. Chromium “is five times harder than steel,” and a plate that has been printed from every day for months shows by microscopical examination that each chromium topped dot retains its original perfection. An impression from a Pantone block made with a 175 to the inch screen printed simultaneously with type on a rough surfaced paper shows how perfect the dot formation is.

Penrose's Annual: the Process Year Book and Review of the Graphic Arts.

Edited by Wm. Gamble. Vol. 29, 1927. Pp. xvi + 127 + 70 + 72 plates. (London: Percy Lund, Humphries and Co., Ltd., 1927.) 8s. net.