I am attending a 3 day course on photo etching at City Lit over 3 weekends.
On Day 1 we were introduced to the principles of photo etching; the three different techniques to get source material onto transparent acetate in readiness to expose to a prepared photopolymer plate. We produced a test plate and printed it to understand the process and how to get tones to print successfully. You can read about Day 1 here.
To photo-etch and print a tonal image successfully from my source photographs or original artwork, I have to introduce digitally texture, like ‘dots’ to the image (like a newspaper image is made up of dots), so that the image photo-exposes and acid etches these ‘dots’ as ‘pits’ to hold ink and so print a tonal image.
Photo into Etching Day 2: Source Image
First of all I wanted to find a really good tonal image so that I could fully get to grips with the Photoshop techniques required for adding texture to the different areas of tone. I found a tonal colour image that worked well in grayscale, but I felt it was a little boring, so I combined it with a line drawing I made of the same subject. Combined in Photoshop using ‘clone stamp’ tool, and ‘multiply’ option on new layers.
Adding Texture to Tones in Source Image
The next step was to separate onto different layers the dark tones, midtones, light tones and white areas of my source image. Using the ‘magic wand’ tool I could make these specific selections of tonal values and copy to a new layer. To add texture to the tonal areas we would simply be applying the filter ‘noise’ to each tonal layer; the darker tones would require a higher value of ‘noise’ than the lighter tones. As I wanted areas to remain as white paper, I did not apply the ‘noise’ filter to my ‘white areas’ layer. See below for a close up of a section of my image for before and after ‘noise’ filter is added. It is a bit difficult to see the ‘texture’ below; in Photoshop when you view ‘actual pixels’ you can really see a difference.
Once I was happy with my filter application I printed out the source image onto acetate and printed a test plate to see how the tones would print.
It is hard to see in the images below but after my first print I felt I could add more ‘noise’ to the darker tones in my image and lessen the amount of ‘noise’ on the midtones i.e to make dark areas darker and midtones area lighter.
I adjusted my image; printed onto acetate and printed a second test plate; which I think printed better than the first – though admittedly hard to see the difference on here.
Anyway I managed to prepare a final printing plate from the 2nd acetate I prepared, so Day 3 will be spent in final proofing of the image; trying different ink colours, trying different paper, trying areas of chine-collé, and maybe trying colour rolls.
(© Catherine Cronin)