Photo-etching is a time tested technique, and the good thing is now it can be virtually non-toxic without compromising resolution, plate durability and traditional plate manipulation. Puretch is a biodegradeable, dry film photo etching resist. It was designed for the highest resolution etching possible with a dry film; the thinner the film the higher the resolution. It is ideal for high resolution halftone positives and fine line etch applications. Puretch is for the intaglio printmaking purist that wants to traditionally etch the image and have complete control over the plate surface and edition.
Two plates exposed with a point light Thicker films will not produce high resolution etchable resists. With thicker films, the light creeps in and undercuts the dots through the thickness of the film and hardens the film against the plate for all except large dots, thus not exposing the metal to the etchant. This diagram also demonstrates the need for a point light and not flourescents. Flourescents cause exaggerated undercutting because light is being cast from many different angles. The sun is the ultimate point light.
One of our customers writes in regarding the feasibility of using Puretch with the electrical etching process.
"I'm delighted to report that it works beautifully! It's very robust and reliable with this etching process. Even very small areas of resist are able to withstand the electric fields. It just hangs on -- I'm having a great success reproducing very fine details."