It has been a long time since I last posted here, but my recent experiments with inking seemed like they were worth a post.
Klara had interest in a Neon with a Fractal design. She had a low res bitmap of a fractal she liked and I was wanting a challenge. There were two distinct challenges for this project:
1.) Taking a low res image and getting it separated into nice shapes and few colors
This was mostly a task I handled between PaintShop Pro and InkScape, but it was far more difficult than I thought. InkScape has a good bitmap tracer, but the image was so low res it didn't come out well. I wound up using a bitmap editor to scale it up then blur and sharpen it to get a better image to start from. I spent a lot of time lowering the image back down to just a few colors before bringing it to InkScape to trace.
In the end we settled on five colors with a brighter feel than the original, but keeping the red on blue basic theme.
2.) Inking multiple colors next to each other
This was more of a challenge. I had done single color inking fairly easily: Etch, ink, then wipe away the ink that flowed out of the etched areas with an alcohol wipe (I use alcohol soluble pens, so don't spill your drink on your Neon!)
I have even recently done two color inking where I do a deep etch, ink, then do a shallower etch and ink with another color. The second color doesn't tend to drop off into the shallower trenchs, and the excess can still be wiped from the unetched top. I might be able to extend this technique to do three colors, but 3mm acrylic isn't very deep and at some point each level has to have a certain height difference or the inking will hit the next layer.
Here is an example of the two color technique: I etched the red of the SuperMan logo deep, then the yellow shallow:
What I tried to do better than this was etching and inking on the back side of transparent acrylic.
I initially tried to etch, ink, wipe in a series of colors. The idea was each time I wipe it would only be the unetched top acrylic being cleaned. This fails pretty quickly and also the acrylic cracks easily when acohol from the wipe is applied to the etched are too much. My first trial looks pretty bad with lots of cracks.
My solution was to not wipe away ink at all, but to overlay it on the previous layer. By doing this and going dark to light in color, I could overlap inks that wouldn't show through the front. Each new etch would expose new transparent area through already inked acrylic.
It worked, but not without some difficulties. The first came fairly quick: The solvent in the paint pens can start to dissolve the paint already on the acrylic, causing a lighter color to get muddied by the darker color already there. I addressed this partially by letting things dry longer and alternating alcohol based pens and Xylene based pens. I tried spraying a clear coat of acrylic at one point and it actually dissolved the Xylene based ink and made it partially translucent. I had to re-ink over it. I did do a final clear coat over the final result, but that was after a long time drying and a layer of alcohol based ink.
Here is my second inking test next to the design. I just chose random colors from my collection of paint pens.
Here are two images of my third test with closer colors. You can see the streaking of the blue ink. It is hard to ink smoothly without the pen smearing what you inked before. And the pens dry out so quick! I can't keep them long.
Here is the first four layers inked, only yellow left to go. Yellow took two etchings as the first wasn't deep enough given the layers of paint and left an orange haze instead of transparent acrylic.
A few pictures of the pieces after being sealed with the transparent acrylic spray.
The final result. I accidentally had the upper left piece rotated. Not to worry, I fixed it
Klara has a few pictures here
The new technique gives me some options to do far more complicated designs, although at a high cost of design and production time.