Wikipedia
Diasec
Diasec is the registered trademark for the original method of face-mounting prints, such as photographs on acrylic sheet. The process was invented by Heinz Sovilla-Brulhart in 1969.
Because of the light penetration and refraction of clear acrylic compared to normal glass, the colours are more brilliant and the image sharper than with standard glass in a picture frame. A Diasec mount is usually of a high gloss finish. Because the print is glued to the acrylic glazing, the result is a completely flat mount of the image.
The print is also protected against ultraviolet (UV) light. Diasec contains anUV light inhibitors to help protect the image from UV light.