Poor highlight contrast
I'm pretty new to this printing thing and I'm having trouble with poor local contrast in the highlights. I have great contrast in the shadows though. I'm doing split-grade printing using a colour head on Ilford MGIV and Kentmere Fineprint VC.
What I'm doing is this:
a) find magenta exposure to get max-black somewhere
b) find yellow exposure (additional to (a)) that gives detail in whites that I care about
The problem is basically that the shadows are composed mostly of the high-contrast layers of the paper and the highlights are composed mostly of the low-contrast layers. The net effect is all-shoulder and therefore pretty flat-looking because the highlights just don't have that bite. If I combine the two exposures into one (by doing partial settings on the colour head), I get an identical result as expected - it doesn't matter if the blue and green light arrive concurrently or not.
I find that to get the contrast I want, I'm burning in the highlights with magenta (blue) rather than letting the yellow (green) exposure take care of them. Net result is I can have a flat-looking print that's about the right overall tone, or a more contrasty print that's too dark.
Is this a fundamental problem with multigrade paper? Do I need to switch to graded paper to solve it? I'm finding that I have (for a given film) a pretty constant ratio of magenta:yellow exposures on the enlarger so I could probably get away with using only a couple of grades.
Or am I doing something wrong? If I could get better results with my current materials, that would be preferable.
Try a weaker yellow filtration.
Make the soft evaluation first, then add the blacks. Soft on hard adds more exposure everywhere, so instead get the highlights you want, then add the black you need.
Jon: you mean weaker yellow as in a different cutoff wavelength, or yellow with more magenta in it? My enlarger has dichroic filters and turning the knobs just winds the filters in/out. So "less yellow" just means more blue gets in - seems to me it would be the same as extending the magenta exposure. Using actual designed-for-multigrade filters could well be different, I don't know.
JBrunner: OK, I shall try that.
Using too high of a yellow filtration can cause a flat tone, ie like trying to print with a grade 00 filter. In cc terms, instead of using, for example 90Y, try 30Y. Does that make sense?
In my experience, getting highlights to properly print on some fibre based papers is far harder than on RC paper. I recently printed a test print on some AGFA RC that I still had laying around. Good overall tonality from highlights to blacks. I than switched to my Kentmere Fineprint VC and started printing. The first thing I noticed was the lack of highlight detail, compared to the RC.
This was something I have only subconsiously been aware of before, as I usually don't proof my FB prints with RC.
However, the solution for me is really to pre-flash my papers. This kicks the highlights into the printable range. With only minimal additional burning in, I was than able to match the RC print.
I am slowly getting more and more convinced that pre-flashing paper is almost a necessity for all fibre based papers if you want to be able to capture the full density range of a negative... and that means shadows as well, as it will allow shorter exposure times, and a slightly lower overall contrast (although that mainly seems attributable to the lost highlights without pre-flashing)
Jon: in terms of discrete filters (00 vs 0 vs 1) it makes sense. In terms of dichroic filters, I'm not convinced it will work due to the mechanics of the filtering but I'll certainly give it a try.
Marco: indeed, I have a number of Ilford RC prints with lively highlight detail and in comparing them with my Kentmere FB prints thought maybe it was a brand issue. I can check that though because I have plenty of Kentmere RC (ignored up 'til now except to check it's speed against the FB) and a couple sheets of Ilford FB though that's warmtone.
I'll give the preflashing a shot... do you preflash white? filtered? Seems to me (totally guessing here) it might be useful to preflash magenta to get an upswept curve: high contrast will register immediately in the highlights but the lower contrast won't have any effect until perhaps VI.
Polyglot, why don't you post an example.... or link us to one you've already posted...
RE: preflashing, I usually do three stops under (=shorter than) the normal exposure.
Note also that with split grade technique you can manipulate any part of the tone curve. But... pardon the insult if it is one... maybe the issue is more to do with your negs? Consider where the details are falling on the density/exposure curve of the film. If the highlights that you'd like to see in the print are way up on the knee, then they will clump/posterize unless you work quite hard in the print phase. If you lower your exposure a bit, some of that highlight detail will slide down along the shin of the curve where it has more slope... hence better highlight differentiation. Of course, shadows will also slide more into the toe, but from what you describe, you can afford that.
RE: Marco's comment about fiber vs. RC, a big issue for any newcomers to FB is the drydown and how much that changes the apparent contrast. I go at it two ways: (1) print a grade or so more contrasty on FB or at least "bracket" the contrast on a test print that I can microwave and quickly see the result; (2) overexpose the FB print and bleach back a bit. Though this method I find that I can get about as much highlight zing as I could ever want.
I preflash with a grade 2. To be honest, I haven't tried any other grades, as I simply assumed using the "ideal" grade 2 would give the best results as it would effect both of the VC "layers". But your thinking may have some usage. Try it out with different grades and report the results here for all of us to learn something new if anything interesting comes out of it...
Originally Posted by polyglot
In terms of exposure time: as required for pre-flashing, I determine the maximum exposure that still leaves my paper white. On my Laborator L1200 with Ilford Multigrade 500H head, that means 0.4 seconds at F16 and enlarger head set at its highest position.
Maybe I just simply don't understand this - I always had the understanding that preflashing reduces the contrast in the highlights and adds more detail (bringing back blown out highlights by reduced contrast).