This materials have important uses in photography and in photographic screen printing, where it is used as an oxidizing agent together with a strong mineral acid.
Potassium dichromate has important uses in photographyand in photographic screen printing, where it is used as an oxidizing agent together with a strong mineral acid.
Gum bichromateprinting was one of the very first stable photographic printing processes, dating back to about 1850. A solution of gum arabicand potassium dichromate, once applied to paper and dried, will harden when exposed to ultraviolet light.
Chromium intensificationor Photochromos uses potassium dichromate together with equal parts of concentrated hydrochloric acid diluted down to approximately 10% v/v to treat weak and thin negatives of black and white photograph roll. This solution reconverts the elemental silver particles in the film to silver chloride. After thorough washing and exposure to actiniclight, the film can be redeveloped to its end-point yielding a stronger negative which is able to produce a more satisfactory print.