Speed system for film. Adopted by the German Government in 1934 and known as the DIN system, the letters being an abbreviation for Deutsche Industrie Norm (German Industrial Standard). Exposure system based on the exposure step to produce 0.10 density above base plus fog. Written as°DIN. A logarithmic system. An increase of 3°DIN doubles the speed of the material, thus 17°DIN represents a speed twice that of 14°DIN.For comparison (12 DIN equals 12 ASA)