I love movies and had this star trek poster that my mother bought for me. So I look on this website to see how to make a back light for it, and with some tweaks to Timmyd_2's tutorial i created this little gem!! so go ahead and read on!!
now go buy or check your poster you have to measure it's width and length min was 36 x 24" (i believe) now go get one 2x4 measure both 24" and 36" ( the 36" will now become 33 due to the 2x4 being 3" in width see picture) you will end up cutting the 2x4 in half to make a total of 4 pieces. now screw all 4 sides to make a rectangle. next fill in and knots of crack with puddy and let dry..... an hour later sand the puddy smooth and make the sides fit flesh with one another. next get black gloss paint and paint it up!