Two research breakthrus in the 1870s paid off by the 1880s The first was cooking the gelatin emulsions makes the grain much larger but much more light sensitiv

Two research breakthrus in the 1870s paid off by the 1880s The first was cooking the gelatin emulsions makes the grain much larger but much more light sensitive. The second (minor) one was adding small amounts of dyes to emulsions make them sensitive to colors other than blue, so B/W looks more realistic and also is obviously more sensitive. http://thelightfarm.com/Map/Books/Osterman/MapTopic.htm http://thelightfarm.com/Map/Books/Osterman/MapTopic.htm