The Ilford set I tested the gray stripe on the step wedge exposure was somewhere near the geometric center of the grays visible. I did not measure the exact reflection density.Quote:
which midtone gray is supposedly to staying constant?
Well that is the tone you need to use to use the filter set correctly. If you try to judge exposure based on black, white or some other gray, you are not using the filter set properly as designed. I'd ignore criticism of a product what was used incorrectly.Quote:
and second, is that always the right tone the exposure is judged by?
The calibration technique from Paul Butzi in the original post describes calibrating to have consistent exposure for the highlights, which I think is what Ralph wishes the filter manufacturer had done.
So if you have a Dichroic head, you have a choice of approaches.
p.s. I use graded paper, so maybe I don't know what I'm talking about.
0.60 logD over paper base is the ISO paper speed point. My 500H, when adjusted, seems to produce this midtone at all grades at the same exposure, for a given negative, which I believe is the meaning of a speed-matched system. This agrees with what I read in Ralph's book, which shares useful suggestions how to take this fact further, and to arrive at an equal highlight while changing grades, which may be more useful than trying to keep a rather dark midtone constant.
More frustration. I ran the safelight test and everything came out "safe." I notice the enlarger has -2 EV attenuator plugged in. Don't know if that makes a difference.
This was done with a grade 3.5 filtration dialed in (75M+15Y) for 7 seconds (f/8). Ilford MG RC paper, 60 sec. in Ilford PQ.
If you'd like to send out one of the negs, I'd be happy to check to see if the problem lies in a thin neg. Send a pm... I'm sure others would be happy to make similar offer... It might be one of those things that is easy to see once its in hand.
[QUOTE=Rafal Lukawiecki;This agrees with what I read in Ralph's book, which shares useful suggestions how to take this fact further, and to arrive at an equal highlight while changing grades, which may be more useful than trying to keep a rather dark midtone constant.[/QUOTE]
exactly.keeping a meaningful highlight density constant is what a truly matched exposure system delivers. anythin else is a nice try.
There could be other issues (fogging of film?) and/or something going wrong in film processing. Assuming you've ruled out printing issues (safelight or other fogging, bad paper, faded filters, bad chemistry etc) it might be best to have someone look at the negatives.
Since you got the time right...
Check the D-76 developer temperature isn't/wasn't/couldn't have been too cold (if so, warm it up to 68-degrees F).
Or maybe it's just that your shots were in flat light (was the crowd shot on an overcast day?), in which case you would expect to print on higher grades.
I'd go back to the Ilford reference on post #3 from Michael R 1974. To simplify while things aren't going well, simplify. Use the single filter settings chart. (Adding Yellow doesn't help higher contrast grades).