. The book of photography; practical, theoretical and applied. Fig. 910.—Steel Burnisher with Wooden H.^ndle. Fig. 913.—Roulette with Milled Li.\es» before described, but of rather greaterstrength. A red powder known asdragons blood is sometimes used in-stead of asphaltum ; in this case a stifferink is required, known as American etch-ing ink. The powder is brushed on asbefore, and the plate heated till the imageassumes a deep brown colour. In a modi- whirler. It is usual to dust the negativewith French chalk to prevent the bitumensticking to it during printing. Develop-ment is accomplished by
. The book of photography; practical, theoretical and applied. Fig. 910.—Steel Burnisher with Wooden H.^ndle. Fig. 913.—Roulette with Milled Li.\es» before described, but of rather greaterstrength. A red powder known asdragons blood is sometimes used in-stead of asphaltum ; in this case a stifferink is required, known as American etch-ing ink. The powder is brushed on asbefore, and the plate heated till the imageassumes a deep brown colour. In a modi- whirler. It is usual to dust the negativewith French chalk to prevent the bitumensticking to it during printing. Develop-ment is accomplished by flowing over withturpentine, aided, if necessary, by gentlerubbing with cotton-wool. When develop-. 914.—Roulette with Dots. Fig. 911.—Roulette with Fine Milling. fication of the albumen process, known asthe blue process, the plate is sensitisedwith bichromated albumen, exposed underthe negative, and flowed over with aspecial solution of aniline violet, chloro-form, benzole, and alcohol, with mastic orasphaltum added as a resist. When thesolvents have evaporated, the plate is de-veloped in water, and, after drying, may
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectphotography, bookyear
