When doing any kind of alternative printing , contact printing is required. Gum Bichromate requires multiple negatives in the CMYK or RGB color space. This requires a repeatable system that is easily done under low light conditions. This can be a system that costs hundreds of dollars or just a few bucks. But whatever it is it better work because nothing is worse than layers out of alignment.
So this is what I came up with and it easy and works pretty well. First I cut the paper to fit the negs with extra space all the way around but make sure it fits in your contact frame. Next I put all of negs together and align them perfectly. Using paper clamps I clamp 1 side. Then I align the opposite side to the paper and clamp that to the paper.
You will notice 3 holes through the all of the sheets. These are made with a leather hole punch.
I use at least 3 holes punched in one side then I bought copper rivets from the local hardware store
Simple . Coat the paper and put the required neg into place. Punch the rivets through the holes. (Make sure the rivets are tight in the holes and be careful not to force through and oblong the holes in the paper.
The contact printing frame has a split back that allows you to clamp the paper in the holder and open the other side. Remove the rivets and clamp the back closed.
I always clean the outside of the glass before it goes in the UV box.
Now your ready to print.
I hope this gives you an idea and helps you over another hurdle.
Any questions or comments please . I appreciate them all
BLUE DOOR STUDIO 