Horgan's half-tone and photomechanical processes .. . ormula will be found to work admirably: Water 10 ounces Le Pages glue 3 ounces Albumen, white of a fresh egg 1 ounce Ammonium bichromate 100 grains Chromic acid 5 grains Le Pages glue is not essential. Any good quality fish-glue will answer; in fact, some prefer what is known as 84 horgans half-tone belting cement, as it gives a still tougher enamel. Care mustbe observed with unclarified glues to filter out the globules offat that may be seen floating on the surface. HARDENER FOR ENAMEL ON ZINC. The hardener used with the above enamel is ma
Horgan's half-tone and photomechanical processes .. . ormula will be found to work admirably: Water 10 ounces Le Pages glue 3 ounces Albumen, white of a fresh egg 1 ounce Ammonium bichromate 100 grains Chromic acid 5 grains Le Pages glue is not essential. Any good quality fish-glue will answer; in fact, some prefer what is known as 84 horgans half-tone belting cement, as it gives a still tougher enamel. Care mustbe observed with unclarified glues to filter out the globules offat that may be seen floating on the surface. HARDENER FOR ENAMEL ON ZINC. The hardener used with the above enamel is made asfollows: Water 30 ounces Ammonium bichromate 60 grains Chromic acid 5 grains Methylated, or wood alcohol 5 ounces The developed enamel-coated plate should rest in this harden-ing bath for from three to five minutes. The secret in the use of an enamel on zinc is to use asstrong a nitric acid bath as possible, so as to etch the platequickly and wash the enamel under the tap only when abso-lutely necessary, as water is liable to soften the HALF-TONE WITH TWO-HUNDRED-LINE Frederick E. Engraving Co., New York and Boston. THE HALF-TONE PROCESS AS APPLIED TO RELIEF-PLATE ENGRAVING AND USED IN EVERY LARGECITY IN THE WORLD. The term Half-tone is a misnomer as applied to thephotomechanical method of making relief blocks for theprinting-press, for the reason that the word half-tone refers only to the intermediate color between the extremelights and the strong shades of a picture, while the half-toneprocess of engraving reproduces all the tones of a pictureincluding the high lights and the shadows. The term similigravure in French expresses the idea better, but theword half-tone has come into the language and willremain. One explanation of the way the word came into use isthat in the early days of the process it was usual to say of itthat it reproduced all the half-tones of the photograph,and this was eventually shortened to the half-tone process,and a
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Keywords: ., bookcentury1900, bookdecade1910, bookidhorganshalft, bookyear1913
