Painting the back of a hologram black is a great way to enhance the contrast of the image. Care must be taken to not destroy the image while painting it. (Do not try this before sealing DCG holograms!)
- Paints that dry too quickly can damage some emulsions by shrinking them and making a crazed glass pattern.
- Krylon Ultra flat black can dry very quickly if not applied in very thin coats.
- Krylon gloss and flat seem to work well.
- Make sure to protect the front of the hologram while painting.
- Paint the edges if you are not going to frame the hologram to keep stray light from entering.
- More thin coats is better than one thick coat.
- Don't try to rush the drying.
- Examine the hologram from the front after painting with a light source behind it to look for any thin spots.