What causes that faded outline, and how to avoid it before you print
A decal itself usually does not damage paint or glass, but the surface underneath it can age differently than the area around it. After months or years of sun exposure, removing a decal may reveal a faint outline where the covered surface has retained more of its original color or gloss. This is commonly called a decal ghost image. It is usually caused by uneven UV exposure, oxidation, and dirt buildup rather than damage from the decal itself. How noticeable it becomes depends largely on where the decal is installed, how long it stays in place, and how much of the surface it covers.