I stumbled into an interesting VC printing filter combo

While printing some pinhole negs yesterday for an upcoming show, I discovered a safelight (sort of). In working with a thin, flat negative requiring a #5 filter, I wasn't getting any exposure at f/32 for 20 seconds. It should have been plenty but completely white paper after 2 minutes in the dev. I opened up to f/16, same 20 seconds and still no trace of exposure after 2 minutes.

Hmmm, suddenly dead developer? Not likely and the person printing at the same time had no trouble. Dead paper in the middle of the box? Not likely. Paper in upside down? Possible but I've been at this long enough to know better plus it was Ilford MGWT matte and it was the middle of the printing session. The curl and surface make identification easy.

Then I had the Homer moment. Filter drawer? Yes inside was the #5 plus the #00 from the previous negative and the light was quite red but I didn't connect it while watching the exposure. It's hardly a "substantive discovery" and not one I'll play with but I thought it was an interesting curiosity.

Steve

The several emulsions on the paper are sensitive to blue and green light to a greater or lesser extent. The #5 filter is effectively a minus-green while the #00 is a minus-blue with the result being not much effective exposure as you have seen. Ilford have a useful data-sheet here.