ray_g said:
Make sure your darkroom is really DARK! And test your safelight!
Otherwise your prints will have gray highlights, and you'll go crazy wondering why. You'll print with contrastier filters, try different developers, different papers. Nothing will help.
There are lots of ways to test a safelight. If you want a really critical one, here it is:
-- You'll need at least two pieces of enlarging paper. For the first one, do NOT use the safelight (yes, this will involve blundering around in the dark a bit.) Put a piece of film leader in the negative carrier (to simulate the most heavily exposed negative you'll ever print) and throw down some coins on the printing paper (you'll see why in a moment.)
-- Now make a test strip, increasing the exposure in small increments. Wash and dry the print.
Examine this print and look for the FIRST test-strip segment on which you can just barely begin to see the outlines of the coins. The segment just
before that one represents the most exposure you can give your paper before it starts to show tone in the highlights. Make a note of the exposure time of this segment.
-- Now you're back in the darkroom with the second piece of paper. Don't turn on the safelight yet! Set up the paper the same way as the first time, with coins etc. Expose it for the same amount of time you noted in the step above.
-- Now cover up the whole sheet, coins and all, with a big piece of cardboard. You're FINALLY ready to test the safelight! Turn it on, pull back the cardboard to expose about 1/6 of the paper, and wait two minutes.
-- Repeat every two minutes, pulling back the cardboard to expose another slice, until you've got one slice left covered. Stop here and process the print.
If your safelight were perfect, this print would look dead white. It probably doesn't, though -- after several minutes of exposure, you'll start seeing the ghostly outlines of the coins. The segment
before this one is your limit of safelight exposure -- the longest you can work under the safelight without degrading the highlights of your prints.
Why did we do print 1 before we actually tested the safelight? Because printing paper, like film, is subject to a phenomenon called "latensification." If you expose it to light just below its threshold of exposure, it temporarily becomes more sensitive to
further exposure.
If you just took a sheet of paper out of the box and did the step 2 safelight test, without doing step 1 first, your safelight test might look fine... but it wouldn't account for latensification. Once you started making actual prints, the paper would become latensified by the enlarger exposure, and be more subject to safelight fog. You'd get veiled highlights and think, "Why? I know my safelight is OK."
. Someone closer gave his setup away, but I missed it by two days.
