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


Grayscales from your computer to the inkjet printer and to the plate.

In this section I am going to show you how to output a Photoshop grayscale to your inkjet printer, this produces a very detailed and smooth stochastic halftone. It seems that when printing a greyscale image at 1440 dpi on the Epson with the output reduced in Photoshop Curves, the ink is very condensed and unpredictable. The best way of adjusting the black output from greyscales (not bitmaps) is in the printing software, the curves can be adjusted there also. This also saves a lot of printer ink and builds in your "aquatint".

original Image

I have been using 900 dpi bitmapped greyscales for my positives. In the past I had tried skipping the bitmap step, reducing the curves in photoshop and then printing at 1440 with no extra print settings and I got very inconsistent blacks. So I returned to the bitmaps, they are slightly granier than the grayscales, but consistent. This printing curve is very consistent and the final etching is characteristic of the inkjet printed grayscale on paper.

The positive for this image was printed on an Epson 3000 using Posjet film and the postscript driver. The image was adjusted by 'eye' on the screen, then I went to File>Print Options... check Show More Options and click Transfer. The same can be done on a non postscript Epsn printer, just go File>Page Setup.

Detail of the purple square above

Slide the bar down to 85% or enter 85 next to 100. Click OK then Print. Print at 1440 dpi, black only, and select photo glossy paper. This curve opens up the blacks so no aquatint is needed. You can save this curve also, then when you return to this screen, click Load, then select the saved curve..

This plate was exposed with Puretch on a NuArc 1000 watt Mercury Vapor exposure unit at a #6 on the Stouffer scale. #7 is the ideal target and easier to process than the borderline #6. It was spray developed for 1 minute, then spray rinsed thoroughly for at least 60 seconds in cool water. The water was removed with high pressure air then hair dried with heat. Nothing mechanical touched the surface during processing. The plate was exposed again (30 seconds) to further harden the resist. The plate was 'wetted' with the developer, then etched in 42ºB ferric, agitating the entire time with a feather, for 11 minutes.
It is recommended that plates be polished for very high res positives because subtle scratches in the plate can cause light refraction and fog small dots. This was exposed on roofing copper posished with a metal polish to almost mirror finish. It was printed with Graphic Chemical- Etching Blue Black.
Visually, the greyscale almost resembles a photogravure, it can now be printed or reworked in traditional techniques.