Solid, but lacking color

I got these as a free experiment from StickerMule, so there was no proof approval involved. The design I uploaded featured some line art with a color overlay (a rainbow of pinks, blues, greens, oranges) against a black background. The result was, the black did NOT have any glitter effect (which is exactly what I wanted and makes the rest of the design really pop!), however the design, which DID have the glitter effect, did not have any color on it. The glitter part was just the default silver glitter with no color in it. They still look pretty cool, and the paper is really thick and sturdy, making for great laptop or even car decals. However I'm not confident yet to order their glitter material again if it's not possible to add a color filter onto the glitter.