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Show PHOTOGRAPHY IN THI DARK. Carman Profeesor Says Light la Net ' Needed for Making Picture. Th light Is not needed for tb printing of photographs la dlaoov- t ery which has boon made by Dr. Wll- y helm Oswald, professor of chomlttry la F th University of Lelpalc. He produce th required changes In the sensitised . paper by the uae of allver oa nega- I tlves treatod with a solution of per- ' oxide of hydrogen. The presence of silver cauaea the elements of the aolu-lion aolu-lion to react against each othor. la a very short time In those placea le whuro thure la allvor In tho negatlv the aolutlon will disappear; In th other spots remain. Thla Invisible plo- lure la then transferred to gelatin paper and finally dovoloped by Iron eulphnta In aolutlon. Gulllo acid ll then applied and the result la a genu- iua-Ine iua-Ine Ink picture. Dr. Oswald declares that In thla method the aeualtlxad do paper will keep indefinitely and th enl allvor can be used over any number of th times. He says the process Is far cheaper and quicker than any now la use, bosldes requiring no light By It any design or drawing can b quickly av copied. |