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Sorry in advance for a simple and probably redundant question but...
I use a VC paper and a Super Chromega D Dichroic II enlarger. Will I emulate a #2 grade paper (of the same mfg, surface, etc.) by printing with NO filtration or some combination of M and Y?
thanx
All I can say is no filters are about grade 2 to 2.5 on most papers in most enlargers. So making negatives that print well with no filters is a fine target to shoot for.
Well, that's what I had heard before but, that's where I get confused. If that's the case, and I throw a #2 filter on my enlarger, will that have a "neutral" impact or will my contrast increase so that the #2 filter is producing a contrast equivalent to a, say, 3 or 4 grade paper???Quote:
Originally Posted by Larry Gebhardt
:confused:
It shouldn't change your contrast much, but I bet there is some change. Your times will get longer. The response of your paper to your enlarger will depend on the type of light bulb it has. The color temp of normal incandescents is warmer than halogens. I imagine that will result in slight contrast changes.
The filters don't create contrast by themselves. They remove blue or green light (plus some neutral density to match speed). So the number 2 filter will let about the same proportion of blue and green through as the bare bulb. But it will be slower. Changing to a grade 3 will let slightly more blue through than the grade 2.
Keep in mind that the filters do not give you the exact grade listed on them. They should be close for the manufacturers paper. The important thing is a higher filter will give more contrast, and that they do well at.
If you are printing with a color head I would use the yellow and magenta filters to control contrast. If you are using a condenser head I would use a filter all the time so the exposure times come out somewhat consistent.
The combined Y and M settings are for a 'constant exposure' series of settings.Quote:
Originally Posted by Pawlowski6132
Otherwise you need only Y, white or M
The best way to know is to test. Throw a step tablet in the enlarger and make prints. Attached is an example of a paper curve with the evaluation points - 0.04 over Pb+f and 90% of D-max. A grade 2 for a diffusion enlarger is between a log exposure range (LER) 0.95 and LER 1.15.
I went through this calibration exercise with my VC enlarger (Zone VI), determining the contrast settings needed to match a print on grade 2 paper. I tested three VC papers, using Ilford Gallerie grade 2 as the standard.
Using a calibrated 31-step 4x5 Stouffer tablet, I first made a contact print on the graded paper, using a constant exposure of 10 seconds, and adjusting the head height and aperture until I made a print with an equal number of solid black and solid white strips. I then measured the density of each strip with a densitometer and entered the data on a graph of exposure vs print density. I also made a straight print of a normal negative at this point.
Then I proceded to make contact prints on the VC papers, changing only the time and the contrast settings, aiming to match the grade 2 print. When I decided I'd come as close as I could, I entered these densities on my graph, and also printed the same normal negative.
In the next phase, I determined the contrast settings needed to achieve the other standard grades, as suggested by Steve Anchell in his book on VC printing.
It was a useful exercise. I now have starting points for contrast settings. I also can look up the exposure change needed when changing contrast settings. I'm convinced that the time spent testing has saved me many hours in the darkroom and a lot of paper.
I also learned two important facts. First, none of the VC papers came close to matching the graded paper at the ends of the scale range. The graded paper had far better separation of tones. In other words, it had more steps of almost black before it reached pure black, and more steps of almost white before it reached pure white. For this reason, I'm still using graded paper if it's appropriate for the particular negative I'm printing.
The second discovery was rather a surprise as a relative newcomer to VC printing; all three VC papers I tested required different contrast settings and exposure times to acheive the same grade. So as Stephen said, the best thing you can do is get a small pack of grade 2 and make some tests.
If you don't have a densitometer, printing a real negative may be more useful to you than a step tablet, especially the 31-step tablet, which is in 1/3 stop increments. It's hard to accurately match the densities by eye. The 1/2 stop tablet might be easier.