3171. Iodized Paper

3171.    Iodized Paper. Brush over the paper on one side (which should be marked) with strong solution of nitrate of silver (100 grains to 1 ounce); then dip it in solution of iodide of potassium (25 grains to 1 ounce); wash it in distilled water, drain, and dry it.

3172. Bromide Paper

3172.    Bromide Paper. Soak the paper in solution of bromide of potassium (40 grains to 1 ounce); then brush it over with strong solution of nitrate of silver, and dry in the dark.

3173. Chromatype Paper

3173.      Chromatype Paper. Simple chromatype paper is prepared as follows: Soak the paper in the simple solution (see No. 3182 (Chromate Photographic Solutions)), and dry it at a brisk fire. To fix the drawing, careful immersion in warm water is all that is required. It is not sufficiently sensitive for the camera.

For Compound Chromatype Paper. Wash the paper with the compound solution (see No. 3182 (Chromate Photographic Solutions)), and dry it. After the paper has been exposed to the sun with the article to be copied superposed upon it, it is washed over in the dark with a solution of nitrate of silver of moderate strength. A vivid picture makes its appearance, which is sufficiently fixed by washing in pure water. For copying engravings, etc.. Another method is to brush writing paper over with a solution of 1 drachm of sulphate of copper in 1 ounce of water; and when dry, with a strong but not saturated solution of bichromate of potash.

3174. Cyanotype Paper

3174.    Cyanotype Paper. Brash the paper over with a solution of ammonio-citrate of iron. Expose the paper in the usual way, then wash it over with a solution of ferro-cyanide of potassium.

3175. Crysotype Paper

3175.      Crysotype Paper. Wash the paper with solution of ammonio-citrate of iron, dry it, and afterwards brush it over with a solution of ferrocyanide of potassium. Dry it in a dark room. The image is brought out by brushing it over with a neutral solution of gold or of silver.

3176. Calotype Paper

3176.    Calotype Paper. The paper is saturated in 1 ounce water, containing 20 grains iodide of potassium, and dried. Then made sensitive by soaking in 1 ounce distilled water containing 20 grains nitrate of silver and 1/2 drachm glacial acetic acid, and dried in a dark room.

3177. Instantaneous Positive Paper

3177.    Instantaneous Positive Paper. Mix 6 drachms of a saturated solution of bichloride of mercury with 1 pint distilled water. Float the paper on this solution in a flat dish. Dry it; take into a dark place lit by a candle with a yellow glass, and render it sensitive by a solution of 38 grains nitrate of silver to 1 ounce water. To print, expose to a perpendicular light from 2 to 10 seconds in summer, about 1 minute in winter; then immediately cover with a black cloth. The image, at first very feeble, is developed by this solution; sulphate of iron, 15 grains; glacial acetic acid, 25 grains; distilled water, 1 ounce. The deepening of tint must be watched, and arrested at the proper moment. Then wash, and fix with hyposulphite.