Photographica said:I'm conducting contrast tests on Ilford Multigrade MG IV FB using Dektol 1:2. I've got a Chromega D Color head for the contrast filters and extra sheet filters to get extra magenta.
I'm contact printing a 31 step tablet negative on the paper for tests and measuring the reflected density from the contact prints.
My problem is that I can barely get to Grade 5 using all of the color head magenta, 150, and another 150 with sheet filters. Measuring the density range (distinguishable steps) with the densitometer, I get 1.5 with 0 filter, 1.3 with M25, 1.1 with M50, .9 with M150, .8 with M200, and .7 with M300.
Taking a shot in the dark, I tried using PF130 stock, from the Photographer's Formulary and got a little less than .7 with M300 (I'm calling it 6.5, my Grade 5 target).
Has anyone else gotten similar results? I may be on the upper end of the Ilford Multigrade paper range and would like to check to see if anyone has had similar numbers.
I've searched Apug for an answer but haven't found a thread with contrast measurement numbers. If this road has been traveled before on Apug, please point me in the right direction.
Cheers,
Bill Riley
Donald Miller said:While I have not tested this paper, I suspect that you are reaching the upper limits of that paper with the diffusion light source that you are using. You would get more out of the paper if you were to use a condenser source and still more yet if you were to use a point light in conjuncton with condenser source.
Bob F. said:Somewhere here (OK found it: (there was a url link here which no longer exists) ) I have plotted MGIV FB and Fineprint FB for grades 00 and 5 - don't know if there is sufficient detail for you to calculate the density range of the MGIV. I just had a look and the original spreadsheet has gone AWOL. X-axis is 1/2 stop steps on the step wedge, developer is homebrew Ansco 130 1+1.
Cheers, Bob.
donbga said:It's been my experience that you can't get a grade 5 with just a color dichro head.
Donald Miller said:Bill,
For instance if you have a negative that has a density range of 1.75 and an unsharp mask with a peak density of .35 (net density range of 1.40) you will print at about grade one with the figures that you posted earlier. Or if you have a negative with a density range of 1.65 and an unsharp mask with a peak density of .45 you will have a net density of 1.20 which should put you in the grade two and one half range.
The key is always matching the scale of the paper...whether that is USM or not.
Donald Miller said:Bill,
I assume that you have transmission densitometric measurement capability since you have reflection. If you measure the scale of the paper and then arrive at the density range of the unsharp mask and negative combination that matches the scale of the paper, it doesn't make any difference whether you get to grade five or not.
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