Puretch processing guide written by Jennifer Page, Cape Fear Press. All rights reserved ©2001-2015.


Description of Puretch™

Photo-etching is a time tested technique, and the good thing is now it can be non-toxic without compromising resolution, plate durability and traditional plate manipulation. Puretch is a biodegradeable, negative working 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.

Puretch features:

click to see enlarged details of resist and etched plates.

  • thinnest photopolymer film on market
  • 15 micron or 0.6 mil thickness
  • highest resolution etch capability
  • 1/1000 inch lines and spaces
  • yields consistent and predictable results
  • easy to apply and etch
  • use on any metal with any etchant
  • non-toxic and safe
  • water based processing
  • durable enough for deep etch
  • wide exposure latitude



2. developed copper plate, Puretch is purple

3. printed etching

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..

Puretch™ advantages

  • conventionally etched plates can print longer editions and/or be steel faced
  • no pre-thinning of film necessary
  • etched plates can be reworked with traditional processes
  • available in 24 3/4" rolls to accommodate 24" wide plates
  • all film is inspected when rolled, no damaged 'end rolls'
  • affordable price

Image applications

  • digitally generated ink jet printed bitmaps*
  • digitally imageset halftones and bitmaps
  • kodalith halftones and positives
  • photocopy on mylar
  • india ink or toner wash on frosted mylar
  • airbrush, pencil, pen or crayon drawing on vellum or frosted mylar...

Processing Basics

  • degrease and clean plate
  • apply film with firm squeegee and distilled H2O
  • bake plate to remove moisture (no long drying times)
  • expose art with UV point light and vacuum frame
  • spray or tray develop 1 minute with water and sodium carbonate solution
  • heat dry and cure in sunlight or UV source
  • etch and print
  • detailed instructions here
  • Solar exposing instructions here no UV lamp or vacuum frame needed
  • Trouble-Shooting Tips here

Other uses

  • photo etching jewelry and serving trays
  • photo engraved metal plaques or signs
  • fine line printed circuit board production (pcb)
  • chemical milling
  • Electro Etching process. 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."

"Stouffer 21 step guide"

Establish perfect Puretch exposure times easily with the Stouffer step guide. There are many different ways for exposing plates. There are an abundance of different exposure systems and processing techniques. The one constant is the step tablet. Use the step tablet as a benchmark for all exposures to achieve accuracy and repeatability.".

Click here for guide on instructions.