New standard densitometer of NIM for visual diffuse transmission density

Abstract The national standard densitometer of NIM can be used for the calibration of photographic film and visual photo. The development of molecular biology image and aerospace technology needs high measurement range and uncertainty of visual density. A new equipment design using hemispherical emitter with optic fiber (HEOF) which is designed independently to enhance the diffuse coefficient of the light source to 0.945 which is higher than the old national standards, 0.02⿿0.03. Thus the measurement range of new standard densitometer of NIM can be expanded to 0⿿6.0 and the combined uncertainties are 0.0015 (0  D D