Silvering is the frosted, silvery sheen that appears when microscopic air is trapped between a waterslide decal and a rough surface — the film bridges the texture instead of touching it, and the air gap scatters light.
Prevention is a smoothness sandwich: gloss-coat the area first, apply the decal onto a drop of setting solution, press out the fluid, soften, then seal. Existing silvering can sometimes be rescued by pricking the film and re-flooding with softener.
See it in context in our panel lining & decals guides, or explore the tools hands-on in The Bench.