>>4133519The orange "base" of color negative film. The base is actually completely transparent, and the orange color is caused by colored dye couplers that lose their color when they turn into dyes. This way the mask is present only where it's needed, in areas with low exposure. It is orange because it consists of two masks in two separate channels. Mask for green channel(magenta dye) is yellow. Mask for red channel(cyan dye) is reddish. After you substract the mask, dyes become closer to "ideal',more clean
