Bichromated gelatin

Photomechanical stencils are of two types direct coatings and transfer films. Direct coatings are either bichromated gelatin or bichromated poly(vinyl alcohol) (PVA). The coated screens are exposed through a positive, washed, and inspected. These screens are used for printing electronic components. They are not practical for commercial work because of the difficulty of reclaiming the screen after use. 

Chrom-gehaltf m. chromium content, -gelatine, /. chromatized gelatin, bichromated gelatin, -gelb, n. chrome yellow (lead chromate) Cologne yellow (lead chromate and... 

The sensitive coating for receiving tho image, is prepared by adding to about a quarter of an ounce of gelatin, dissolved in eight or ton ounces of water, by the aid of heat, one ounco, by measure, of a saturated solution of bichromate of potassa in wator, and straining... 

The principal components of Carbonites are NG(gelarinized or not with collod cotton), K or Na nitrate and spent tan bark or woodmeal. Some Carbonites contain Ba nitrate, K bichromate, Amm oxalate, gelatinized silicic acid and soda ash or Mg carbonate... 

Natural polymers such as albumin, gelatin, fish glue, shellac, and gum arabic received attention up to the early 1900 s, after which time other materials such as bichromate, diazo compounds, iron salts, and silver halides were added to resins in order to hasten or accomplish their crosslinking. These systems were neither photopolymerization nor photocrosslinkable polymers. Instead, the added second component, when excited by light, produced a species which itself caused the formation of radical sites on a prepolymer or polymer chain which then led to cross-linking. 

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