I print waterslide decals on the laser printer at work. If I want to use white or gold in the design, as is usually the case, I print the decals in mirror image and hand paint the desired color onto the back side of the decal.



When I do this, I put a thin smear of water soluble glue on frame where the decal will go, and put the wet decal over this. Then I carefully squeeze all the water and glue out from under the decal, working from the center outward. It's a little more difficult than putting the same decal on the usual way. Once the decal is in place, it takes a day or two to fully dry; once it's dry it is very stable, especially if clearcoated.