Quote Originally Posted by Ken Nadvornick View Post
I dunno' Greg. For b&w all I use is a single layer of Roscoe #19 Fire between glass sheets without any diffusion. The Roscoe spectral transmission chart says this should be sufficient. And for both my CD and pre-flashed fogging tests of Ilford MGIV, it is.

This filter is located in the lower filter position. The vanes contain only sheets of black mount board. That allows me to adjust down to total darkness for easel framing and focusing.

Ken
I tried that after your posts in the other thread. I had fog after very short times. I test using Kodak's method of using safelight exposure before a medium gray exposure, and again after a medium gray exposure on separate pieces of paper. Using the filters I mentioned gave me safe times after exposure of up to three minutes with the vanes fully open, and well past seven minutes with them fully closed. With just the #19 filter in place I had safe times of less than one minute fully closed after the paper received printing exposure. Just my experience.

I should note that I was using Ilford MGWT paper. Regular MG gave slightly longer safelight times, though I don't know why since printing times are shorter with MG than MGWT.

And, yes, I was meticulous about other sources of light being an influence. Even the glow from my watch face was eliminated from the darkroom first.