Adhesive lettering adheres best to smooth, clean glass surfaces, such as those found on classic shop windows, glass doors, or office windows. It is important that the surface is flat and not textured. Standard clear glass is ideal and poses no issues in practice.
Heavily textured, rough, or coated glass surfaces are not suitable or only suitable to a limited extent, as the adhesive cannot make even contact there. If you are unsure whether your window is suitable, the rule of thumb is: If the glass feels smooth and can be cleaned normally, it can usually be covered with adhesive lettering.
