I hope this is the right forum; if not, I apologize in advance. I'm working on a 3d face scanner project, where I have a camera and a DLP projector very close to each other. This wikipedia entry titled "Structured Light 3D Scanner" explains very well what I'm trying to do. Basically, I take a picture of the face and within 100ms take another picture but with a projected binary (stripes) pattern (using an optical mask). The DLP projector has a visible light filter attached, so only near IR light is transmitted. What I have done is printed a binary black/opaque pattern onto a transparent sheet. However, the black does not completely block the transmitted light. Hence, I was wondering whether there is a chemical substance with which I can create a high-contrast optical mask (so the black is really black)? Or does anybody know of any commercial products? Thanks!