Horgan's half-tone and photomechanical processes .. . n the sensitive gelatin or albumen coating onthe stone. The negative is stripped from the glass by themethod described elsewhere, and the side that is to comeinto contact with the stone is smeared over with vaseline,glycerin, castor oil or olive oil, taking care not to formsmall bubbles. The film is then turned over on the sensi-tized and slightly warmed stone and slid into its properplace, after which a thin sheet of paper is laid over it andthe surplus oil squeegeed out from between the film andstone, with a roller squeegee by preference.
Horgan's half-tone and photomechanical processes .. . n the sensitive gelatin or albumen coating onthe stone. The negative is stripped from the glass by themethod described elsewhere, and the side that is to comeinto contact with the stone is smeared over with vaseline,glycerin, castor oil or olive oil, taking care not to formsmall bubbles. The film is then turned over on the sensi-tized and slightly warmed stone and slid into its properplace, after which a thin sheet of paper is laid over it andthe surplus oil squeegeed out from between the film andstone, with a roller squeegee by preference. The oil is thencleaned from the surface of the negative film with a softrag and benzin. After printing in sunlight, electric light(or, if a cloudy day, see that the light reaches the film atas near right angles as possible), peel the negative carefullyfrom the stone, in the darkroom, wipe off the oil with asoft rag and benzin and then develop with water. Thismethod can, of course, be applied to metal plates too largefor the printing-frames at FROM A NEGATIVE ETCHED WITH NEEDLE York Daily Graphic, June 26, 1873. NEGATIVES ETCHED BY HAND. ALSO THE VARNISH FOR SCREEN RULING HERE USED IS A* MOST VALUABLE FORMULA. There is a little-known method of producing negativesmechanically that was practiced on the New York DailyGraphic from 1873 to 1876. It has some advantages forexceedingly fine engraving and for scientifically accuratework. It is here published for the first time. Instead of drawing in waterproof ink over a photographon plain paper, as described elsewhere, a photographic posi-tive is made from the copy on glass, similar to a magic-lantern transparency. This positive must be the exact sizeof the intended reproduction of the photograph, engravingor lithograph. It is better to make this positive by thecollodion process, either wet or dry, though a gelatin dryplate can be used. A MOST VALUABLE VARNISH FORMULA. When the positive is dry it is slightly warmed an
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Keywords: ., bookcentury1900, bookdecade1910, bookidhorganshalft, bookyear1913
