Heliogravure VIII – More About Etching

In a previous post have been exposed a general method to reduce the number of etching baths and rationalize the relationship between the total etching time and the partial etching times in the respective baths. Here we will analyse a sequential fine tuning of a couple of ferric chloride baths having previously determined a total …

Heliogravure V – About Etching

In photogravure on copperplate, etching  is commonly done by immersing the plate in several solutions of ferric chloride of different concentration. As the pigmented gelatin is thicker where the image tone is higher, the trick is to allow the ferric chloride to penetrate beginning by the thin gelatin in the shadow areas and progressively do …