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The réticulation occurs all the times when the gelatin, inflated by the water, until occupy a volume upper to the one that it occupied during the casting is prevented from dilating laterally both by its adhesion to the support and by the existence of a superficial tanned coat (consecutive to the sunstroke made in the light U.V. through the negative, or by chemical substances in the case of a direct drawing on the gelatin). This is thus during the wash in the cold water intended to eliminate the excess of bichromate that occurs this réticulation. - This is understandable by the fact that during the drying (see phase of étuvage of gelatin), the gelatin remains viscous during the evaporation of the water which it contains. It is only when there is not any more approximately than 25 % of water that it takes itself in frost. The contractions during her solidification are thus very weak.
- The dumping in some cold water quickly determines the inflation. In the parts of the superficial coat of the gelatin dichromated, which were tanned by the action of the light, the réticulation is practically immediate. The maximum inflation varies from a stitch to an other one, and are tall all the more as the quantity of light received during the pose was lower (clear part of the final image).
- The average diameter of the stitches of the network is equal to the thickness of the part not tanned of the total thickness of the coat of gelatin. Where from the importance not to put a too important thickness of gelatin on the glass plate.
- During the inking of the plate, the summit of wet grains refuse the ink which is accepted in the dry hollows.