My aim here was to use aquatint tones to produce a detailed image without any line. Not that I have anything against line. I've always struggled with tonal drawing/painting, being much more of a scratchy line kind of person, so this was in interesting challenge.
The process I used was a combination of Acrylic aquatint and toner transfer. A watered down acrylic medium and acrylic ink solution was sprayed on using a £10 airbrush.
I used photoshop to make masks for the three levels of etch by making a mock version of how I wanted the image to look. Each tone painted on a seperate layer, then converted to black and inverted - I need the white areas masked on the copper which means they need to be printed black.
After a few epic fails with various shiny papers, I had a forehead slapping moment when I discovered that the best result came from ordinary photocopy paper. My laser printer, a cheapy Brother HL-2035 (with third party toner cartridge) does not seem to be overly generous with the toner so I ran it through twice. Took me and my middle aged brain a while to work out which way to feed the paper in for the second going over and no matter how many times I tried, it was always out by a mm or so (which means this would not work for very fine detail).
The first mask (the white areas) was stuck to the (already sprayed with acrylic) PCB by running through a laminator a few times, till it gets too hot to handle really. The boards are pretty thick and the laminator grumbles a bit but so far so good. Then the whole thing is dunked in water till the paper comes away, leaving the toner mask stuck to the board. That is the theory. In reality, the toner never seems to stick too well at the edges, thinking this may be due to my greasy fingers handling the edges? Anyway, I tried to mask them in with my trusty Sharpie pen but as can just about be seen at the top and bottom edges, this does not produce as good a mask as the toner. The board is then floated upside down, stuck to its foam lilo bed for 1 minute for the lightest tone.
Rinse and repeat. I did another 1 minute for the next tone (so 2 minutes in total, come on, keep up), then another 6 minutes for the darkest tone (a total of 8 minutes). So that's 3 seperate masks, 3 times in the Edinburgh Etch solution.
Now, 3 layers of toner are an absolute pig to get off. Next time, I will make each mask with the previous subtracted from it rather than just pile it up, so the total layer is only 1 thickness of toner and not 3. Don't know why I didn't think of that first. Anyway, much scrubbing with nail varnish remover (for the acetone) later and a very satisfactorily etched board appears.
Again, printed with Sepia Caligo ink onto BFK Rives paper. A successful day.
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