File:Horgan's half-tone and photomechanical processes (1913) (14593791278).jpg

Identifier: horganshalftonep00horg (find matches)
Title: Horgan's half-tone and photomechanical processes ..
Year: 1913 (1910s)
Authors: Horgan, Stephen Henry, 1854-1941
Subjects: Photomechanical processes
Publisher: Chicago: Inland Printer Co
Contributing Library: Getty Research Institute
Digitizing Sponsor: Getty Research Institute

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e use of asharp palette-knife between the shellac and the zinc, whenthe film will split off. For a permanent support the surface of the zinc isroughened with sandpaper to which the shellac adheres 68 HORGAN S HALF-TONE firmly. Rubber, gutta-percha and even strong glue havebeen used to secure the gelatin-relief film to its support. Large editions have been printed from the original gela-tin film without electrotyping. The gelatin was, however,after washing out and dried, either exposed to light fromthe back for a long time or hardened with a bath of chromealum. It was also the custom with some operators to exposethe back of the film to light for a short time before the firstwash-out. It was said of the washed-out films that they could befiled away for use at any time. Such films in the writerspossession for twenty-five or thirty years are even morebrittle than if they were glass, due possibly to the continuingaction of the bichromate left in the film and the evaporationof the glycerin.
Text Appearing After Image:
LINE ENGRAVING.Globe Engraving & Electrotype Co., Chicago. RELIEF-LINE ENGRAVING. WHICH IS THE MOST IMPORTANT OF ALL THE PHOTOMECHAN-ICAL ENGRAVING PROCESSES. The engraving of drawings in lines, or the reproductionof type by photoengraving, comprises the greater part ofprocesswork the world over, and still the complaint can bejustly made that in most cases either no improvement hasbeen made in this class of engraving or frequently the qualityof the work has deteriorated. The causes for the deterioration can be briefly stated.Line engraving, and particularly the reproduction of type,requires even greater skill on the part of the workmen thanhalf-tone engraving, and still the charge for the work usuallydoes not pay the cost of producing it properly, consequentlythe work is slighted. Then the same collodion is used forline-negative making that is used for half-tone negatives,which should not be done. And worst of all, the line opera-tor uses cutting solution on the negative which des

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