Thanks for the hi res pic.
A lot of people already know this about backglasses, but there are different layer features for different styles. I have noticed 3 basic features regarding ink layers.
This is the easiest to fix because the final or top layer is a light blocking mask. It represents any non-illuminated areas on the glass. Most factory masks will look silvery gray when viewed on the back.
This feature is not visible on the front of the glass unless illuminated from the back. Typical use is the match numbers. It consists of a first thin layer of base color(s) directly on the glass that matches the surrounding artwork. Then a layer of light diffusing color shaped by the number or word (TILT). The feature is not masked.
You can see these on the front and light up as general illumination or indicators. The feature is usually a light colored ink/paint directly applied to the glass and never masked.
Damaged masked areas are almost always the easiest to fix. Really the only problem I find is color matching. If the repair is not a *very* dark color then it will often need a mask applied or else it will be translucent and thus an ugly repair, letting unwanted backlighting through. I use a thick layer of black for a mask. The repair paint can be applied by regular brush or air brush.
Hidden, and especially translucent repairs *must* be applied by air brush with the only exception of very small areas and lines. If you use a regular brush then the unavoidable brush strokes look terrible when back lit. The base color that is part of the surrounding artwork for a hidden feature must be thin as possible especially if its color is dark so the diffuser layer behind it can shine through. The diffuser on a hidden feature is the actual number or character seen on the front when illuminated.
-->I like to use Liquitex Titanium white for diffuser. It applies evenly and transfers light well.
I always apply the diffuser layer thin as possible for maximum light transfer.
It takes as much back light as possible to illuminate the diffuser paint. That's why I painted the head's wood insert white. I am most definitely NOT a fan of LED lighting on EM's. Period. But that's a debate elsewhere.
I began collecting the things I need this evening. It started by inspecting the damaged areas and noting what colors I'll need. You may be surprised how many colors are repeated in different areas on a backglass. For example on my back glass, the light brown ceiling, people's skin and the billiard rack are all the same brown.
Some colors like black and white I already had. I am not skilled at mixing colors so I took photos of the colors with my cell phone and took it to the art store and matched close as possible with their stock. My photos didn't concentrate on pictures or patterns but rather colors. Here, for example shows 7 colors (+generic black and white) to match:
More such photos help cross-verify the selections in the store.
I noted the high reflectivity of the glass, that the darker colors are my target.
Tonight I set up most everything I'll need on a padded table.
Various tubes of colors both new, and stock I already had. I like Liquitex heavy body but other brands found in the store more closely matched my project. I'll see how the other brands do.
Other things are a heavy bowl to support the glass when overhang over the table, tape, paper, pencil, straight edge, pinpoint and broader brush, my cheap but trusty Badger 350 air brush, compressor, razor blades, mixing sticks and a color mixing wheel comes in handy.
I also have a #44 socket wired to a 6v 3a wall wart to test repairs while back lit. Also a bright LED trouble lamp to spot otherwise hidden ugly cracks and check translucent paint consistency. Also a magnifying glass for my poor vision and bright open space to work.
I stabilized the existing ink/paint with Tripple Thick last month.
I hope to start on this tomorrow evening. You'll get to see, step by step how I destroy this glass.