Neutral Density Window Films are made of deep dyed (color stable) polyester films, laminated with acrylic adhesives with UV inhibitors.  Solar Graphics’ ND (Neutral Density) Films are true gray, designed for blocking percentages of visible light transmissions (VLT) from 400um to 700um and blocking 99% of the UV’s from 200um to 400um.  ND Films are used on glass to control the density of light or “glare” from most incoming light sources, such as ambient light coming in through windows.  This control neutralizes or stabilizes light for better digital camera and photo production operations, extending the quality of color and resolution. (Additional F-stops)