A safelight test that is little more complicated but more informative than the Kodak test cited in post #2 is to first make strips of varying white light exposures in one direction across a piece of photo paper, and then make strips of varying safelight exposures at right angles to the first strips.
In detail, raise the enlarger head to its maximum height and stop the lens down to its minimum opening. There should be no negative in the negative holder. In total darkness place a sheet of fresh paper in the easel. Cover the 1/6 of the bottom of the paper. Make a 1 second exposure. Cover 1/6 more of the paper and make another 1 second exposure. Cover 1/6 more, and make a 2 second exposure. Repeat the process with 8 and 16 second exposures. I find it easier as well as quicker to move the covering material up at the 1, 1, 2, 4, and 8 second intervals. This will also eliminate any error due to the intermittency effect and light lag in the enlarger lamp. Now place the easel and paper under the safelight and cover 1/6 of one side of the paper. Turn the safelight on. After 1 minute, cover another 1/6 of the paper. At additional 1, 2, 4, and 8 minutes expose more 1/6 strips. After 16 minutes of safelight exposure turn off the safelight and develop the paper in darkness.
With your darkroom setup you may not need the longer enlarger and safelight exposures. You may also want more precision than provided by these one stop increments. If so, make the exposure steps of 1, 0.4, 0.6, 0.8, 1.2, 1.6, 2.4, 3, and 5 units. Yes, that’s too complicated for me, too.
Analyzing the results of this test may aid one in predicting the effect of pre-exposing film or paper to alter the toe of the characteristic curve of those materials. The results of this surprised me.
