ok so l wanna make some advertising displays like these:
http://brodwax.com/ILM.htm
but l need to know what kind of material are they using to make the pictures out of? what kind of paper is it?
i'm pretty sure l could make the frame and install the lights but the paperand where to get it is my problem. please let me know if you have any ideas. would love to make a big light sign with this.

The material being used for such light boxes in prof. printing houses is often a translucent vinyl foil (e.g. Avery Series 5500 QM, 50 my thickness). Just check for printing offices offering foil plots and ask them for assistance. If the foil / light box will be used in an outdoor environment you need prof. advice, also with the light system.