. The book of photography; practical, theoretical and applied. ructurecapable of holding 3,000 gal., and measur-ing 48 ft. by 6 ft. by 30 in. The sensitivepaper, with an opaque outer covering, wascarefully attached to the wheel, and thedeveloping vat run into position, the pro-tective covering being removed as thepaper was allowed to go into the development was employed on partswhich appeared too light or too dark, andfinally the huge enlargement was sprayedwith a weak solution of acetic acid appliedwith a hose to stop development. Anothervat with acetic acid solution was then
. The book of photography; practical, theoretical and applied. ructurecapable of holding 3,000 gal., and measur-ing 48 ft. by 6 ft. by 30 in. The sensitivepaper, with an opaque outer covering, wascarefully attached to the wheel, and thedeveloping vat run into position, the pro-tective covering being removed as thepaper was allowed to go into the development was employed on partswhich appeared too light or too dark, andfinally the huge enlargement was sprayedwith a weak solution of acetic acid appliedwith a hose to stop development. Anothervat with acetic acid solution was then run print may be produced by sulphocyanideof ammonium and gold, on one which isbrown from piolonered development. Take20 grs. of ammonium suiphocj^anide, anddissolve in 1 oz. of water. Mix 2 grainsof gold trichloride with 1 oz. of gold solution should be added to theother in small portions, well mixing. Theprint is immersed in this until of thedesired colour. Sepia Bromides. These are most commonly produced bythe hypo-alum treatment. This gives, me. Fig. oiU.—ilETOCCHING FINISHED into position, and the wheel rotated inthis for twenty minutes. After anotherrinsing, it was treated with the fixing bathfor three-quarters of an hour, and againflushed. Finally it was drawn off thewheel, and washed in frequent changes ofwater for eight hours, 66,000 gal. of waterbeing used in the process. Drying occu-pied ten hours, and it was then mountedon canvas and retouched. An idea of themagnitude of the retouching operation isconvejed by Fig. 340. Toning. The normal colour of a bromide printbeing black, any other colour must be pro-duced by after treatment. A blue-black with a bath that has begun to work pro-perly, a rich sepia colour. Dissolve 5 hypo, in 35 oz. of hot water, and add1 oz. of alum. The addition of the alumwill cause a thick, milky precipitate. Thisprecipitate must not be filtered off, butremain suspended as far as possible in thesolution. The prin
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectphotography, bookyear
