Our typical mask type is low reflective chrome oxide on soda lime glass or quartz (fused silica). These are very high resolution, easy to clean, and hard wearing. Soda Lime Glass is a very popular low cost alternative to quartz , with high light transmission in the visible spectrum. Quartz has a much lower thermal expansion, and a slightly higher light transmission rate. The chrome coating has an OD (optical density) >3 and has a low reflective oxide coating on the top surface, but equally can also be supplied in high reflective or blue oxide variants. Please also see our "special materials" section which contains different materials, special chrome coatings, various thickness plate etc.