CHEMICALS USED IN COLLOTYPE
- Preparation of acid fluorhydrique (10cc of acid in 40° for 1 liter of water) : we overturn on the plate by beginning with edges and we spread with a scrubbing brush. The gelatin crinkles. We scrape with a steel spatula on your edges of the surface then the coat lifts up itself in a single film. Rinse in the water and scrape edges in the pumice. We rinse well in the clear water. (Noted : the technique of the acid fluorhydrique was collectively used for the lamination of pictures glass employed in collotype, because he allows the complete unsticking and the quasi–instantanné of all the coat, without altering it.
- For one plate dries, put inflating the gelatin of the plate in the water before crossing fluorhydrique acid ; useless operation for a plate which has just ended an edition, because of its residual humidity. The cleaning of patches by means of washing soda, although less fast, present fewer dangers.