FP4/Pyrocat HD (in glycol), 1:1:100.
FP4/Pyrocat HD (in glycol), 1:1:100.
What I personally do with pyro-stained originals is to generate the contrast mask using blue light to make it inversely proportional to the yellowish-brown or greenish-brown pyro stain itself. Ortho film will obviously work, since it's mainly blue sensitive anyway. But I'd try to keep things simple, and just use FP4 for the mask too. It's an excellent film for masking. But don't develop the mask itself in pyro or you might get excess cumulative edge fog. It's better to have something non-staining for the mask itself. I use very dilute HC-110 with a pinch of benzotriazole to act as a toe and fog cutter. I can provide the specific formula later if there is interest. The idea is to get a very low contrast straight line mask, aiming for a DMax of only about .30 above fbf, at least at the start of the learning curve. What you're really doing is shadow masking all the way up into the highlights, more and more gently, then actually printing to a harder grade to accentuate micro-contrast, and optionally edge effect too. A happy result would be more subtle sparkle and detail. One can experiment with manual lightbox registration for earlier stages of the learning curve; but reliable results without going insane really need investment in dedicated gear. But the FP4 originals you already have should be excellent candidates for this kind of enhancement.
“Micro contrast” and edge effects are the same thing.
John, in the context of black and white, the idea behind a basic unsharp mask is the following:
1. Since the mask is a thin positive, when printed as a sandwich with the original negative overall contrast is reduced
2. Since the mask is slightly blurry, when printed sandwiched with the original negative, the mask causes hard edges in the image to increase in contrast
So, overall contrast is reduced, but at sharp boundaries in the image (hard edges, details, textures) the original contrast is retained.
When printing the sandwich, in order to compensate for the reduction in overall contrast you need to print at a higher grade, which gets you back to where you began when printing the original negative by itself. However printing at a higher grade means sharp boundaries now have more contrast than they did when printing the original negative by itself. These higher contrast edges in the image are what enhances the subjective sense of sharpness in the print.
An illustrative example. Suppose you have a negative that prints at grade 2. You make an unsharp mask and sandwich it with the negative. Now when you print, overall contrast is too low, but contrast between tones at sharp edges is the same as in the original grade 2 print. In order to get overall contrast and tonality back to where you want it, you need to print at grade 3. In your final print, overall contrast is now back to where it started at grade 2, but edge contrast is at grade 3. This makes fine detail more punchy.
Not really in this case, Michael. It's an important distinction because visible edge effect can be differentially controlled by masking, just like with digitally controlled edge effect. That's why I hinted there's more to it than just basic contrast masking. When people don't have precise registration gear or know specific techniques, they tend to make masks too unsharp for sake of easier alignment; but then they lose control of precise edge effect. He's already enlarging the heck out of his 5x7's. Any further edge sharpening would need to be very carefully tuned or it would stand out like a sore thumb on that scale. A good illusionist never shows their hand. In this case, think about killing two birds with one stone - tonal gradation enhancement being one thing, visible edge effect another (not to be confused with the micro Mackie line topic, which is not even visible on a diffused UNSHARP mask itself). Lots to explain, but otherwise, pretty darn obvious in before and after prints (not web images). It's actually easier to do than to explain.
Edge effects and micro contrast are the same phenomenon. In direct development, the are caused by diffusion. With unsharp masking, they are caused by the fuzziness of the mask. From a sensitometry perspective the result is the same. The difference is that with masking, more extreme effects can be created, all the way to halos around objects.
You're getting hung up on terminology and missing the point, Michael. Instead of micro-contrast (which is indeed a real effect somewhat controllable by masking), think of micro-gradation or internal tonality expansion as another cumulatively controllable outcome based on contrastier printing. We've had this conversation before, but in reference to why I prefer masking to traditional Zone System minus or compensating strategy, which tends to do the opposite, and flattens internal tonal contrast - my smashed peanut butter and jelly sandwich analogy. This is a contrast issue, whereas any mask halo effect is diffusion sheet and light source related. Hence they can be independently controlled.
Halo edge : controlled by size of point light source in relation to angle of incidence, as well as by degree of diffusion via frosted sheets.
Internal gradation : degree of paper contrast increase in relation to density of mask
There is no micro-gradation vs micro contrast. It’s all edge contrast. You might be confusing it with Planck-scale contrast, but only your darkroom equipment can generate the energy required to probe those effects.
The smashed peanut butter and jelly was something else, and we probably agreed on that.
John Layton,
You have the kit and the coaches... go for it.
I'm amused that Photosharp unsharp masking uses similar parameters, but bemused that everyone who uses it has ruined the look.
So I would go for it but touch lightly because you don't want to look like everyone else.
Folks...I truly appreciate this discussion - thank you!
I likely will not get around to this any time soon...but seeing as I have the Radeka kit for 4x5, and I ultimately (might) want to mask more 5x7's than 4x5's - my thought at this point is that I'll just cut a "spare" 5x7 negative (one of multiple negs from a desired example) to fit ...making sure that this section contains an appropriate mix of relevant material - and work with this up to my desired size. This should give me enough to make a comparison to one or more existing 40x60 prints.
If the above experimentation (assuming I can either get it right, or find someone to help further until I do) then indicates that I would indeed find such masking beneficial - then I'll go ahead and either find or build a masking system which would either fit my Zone VI (series 2) enlarger, or perhaps a larger one to fit my DIY 8x10 horizontal enlarger - whichever makes sense in terms of available negative stage area, and how much of this might be required to accommodate the masking/registration gear. Make sense?
Makes sense to me.
Lynn Radeka’s kit explains things quite well.
For a nice beginner’s demo, Greg Davis (first reply in this thread) made a video on his Naked Photographer YouTube channel.
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