Formation of Cyan Leuco-dye in Color Photographic Materials Processing and Methods of its Prevention

During the chemical processing of color photographic materials,simultaneously three dyes,i.e.yellow,magenta and cyan,are formed in the respective photosensitive layers treated with the color developer;but owing to the fact that the electrode potential of the cyan dye leuco-derivative is much higher than those of the yellow and magenta dyes,thus cannot be oxidized by quinone diimine,consequently only the cyan dye leuco-derivative is actually formed during the color development and should be transformed into the cyan dye in the bleaching bath.Any untransformed cyan leuco-dye remained in the cyan image of the final color image will directly damage the color image quality.This paper elucidated the harmful effects of the cyan leuco-dye,the causes of its formation and methods of its prevention.