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


Troubleshooting tips

Problem: Film coming off when removing top mylar for development

Cause & Trearment:
Moisture is not being removed from film after water lamination. Use a blown heater or hairdryer to remove moisture from film and improve adhesion. If you are not able to get plate surface up to 180ºF then dry the plate for much longer time than recommended. Humidity in shop may also be too high, humidity should be 60% or lower. Plates can be dried overnight without heat in proper humidity.

Problem: White, cloudy spots forming under film after lamination

Cause & Trearment:
Usual cause is contaminants. Powdered cleansers not rinsed fully are also to blame. If problem persists, eliminate powdered clenser and switch to a good metal polish, followed by a high strength degreaser such as Right Stuff. Do not use cleaners with orange oil or D-limonene. DO NOT SAND YOUR PLATES. Sanding plates makes microscopic valleys and ridges that can trap cleaners and prevent Puretch from adhering because it may not let Puretch reach the valleys. This method only works for thicker films and is not recommended for Puretch. Sanding plates creates too much plate tone and can also negatively affect resolution fidelity because surface is roughened.

Problem: Not able to etch small dots in hilghights

Cause & Trearment:
Exposure too long. Shorten exposure and use a Stouffer to determine exposure times. Do not adjust development time, always keep this standard and adjust exposure instead. Flourescents can cause this too, always use a point light; one clear bulb light source from one point.

Problem: Film breaking down during development

Cause & Trearment:
Exposure too short, use a Stouffer to determine correct exposure, do not adjust development time, always keep this standard and adjust exposure.

Problem: Plate not biting evenly

Cause & Trearment:
Plate may be overexposed. See Stouffer info above. It is also helpful to wet plate surface with Puretch developer or soft water prior to placing in etch. The developer is a slightly base solution and lets the etchant flow quickly into the metal similar to how a spit bite medium works. Plate may not have been hadled carefully after development, do not touch plate surface with fingers after drying. Plate may be oxidising from slow drying. A good way to dry plates after rinsing is to blot surface with a clean piece of newsprint, then air dry or hair dry. Etch that day if possible to prevent oxidation of exposed copper.

Problem: Film not adhering at edges of plate

Cause & Trearment:
Do not bevel plates before lamination. A slight burr from shear may cause an air pocket at edge, carefully knock this off with a scraper or file without over beveling. Clean back of plates around edges to keep grease, etc from creeping in at edges. Always trim film from front side of plate with very sharp blade. Do not prop plates on edge for drying, this can cause delamming at that edge, dry flat instead.

Problem: Small holes in film and etch

Cause & Trearment:
Dust and dirt particles in lamination or exposing unit. Always work in a clean, dust free lamination room and close off or filter air vents. Use compressed air on plate prior to spray and lamination.