There are other approaches if you have a cold light i.e flourecsent that produces more blue light.
Anchell provides data from Joe Englander's setup with a cold light head; this same setup could work for you by first including a cinegel colour corrector to shift from your tengsten source to a more daylight response, then experiment with the following setup for more conventional non-split filter printing techniques. As you see, these are mostly cinegel, which is more common in film than theatre, though some theatre lighting designers that do pull from the cinegel line when selecting thier pallet, particualrly in lighting musical theatre for a two colour yellow/blue or green/magenta wash.
389 Chroma Green
3304 Tough Plusgreen (30G)
3315 Tough Half Plusgreen (15G)
3313 Tough Half Minusgreen (15M)
3308 Tough Minusgreen or Roscolus 37 (30M)
3302 Full Bue (80A)
68 Sky Blue
my real name, imagine that.
Howard Bond wrote an article several years ago (Photo Techniques) in which he used/tested the magenta and yellow offerings from Roscoe--these work as well,
including under the lens with no degradation.
You're right. We use mostly Roscolux and, only occasionally, Cinegel.
We've got tons of #68 but none of the others you mention. I suppose I could order the right colors. They only cost about $5.00 per 24" sheet but, at that price, I could just buy the Kodak Polymax filter set and be done with it. Right?
Still, there's no reason I can't try Rosco for the purposes of experimentation.
Is there a place where I can find out what wavelengths of light different multi-contrast papers respond to? With that information I could go through the transmission charts and pick which colors match. If I have a set of filters on hand I could also just go through the swatchbook and find the closest matches and use those as a starting point.
That's the problem, ok. No one releases those numbers for the consumer, or at least I haven't seen them and I can understand why. Those data are probably a closely guarded industrial secret, much the way a chef will not release his seasoning recipes for the speciaties of the house. Aside from detracting from sales of VC filters, the whole thing will get very complicated very quickly. For starters, I don't think that the hard and soft contrast emulsions are exclusively sensitive to blue and green light respectively. I think it's more like the hard contrast emulsion is primarily sensitive to blue light and to a lesser degree sensitive to some green light, while the soft contrast emulsion is primarily sensitive to green light with a lesser sensitivity to blue light. So now you're faced with determining the blue/green ratio for the hard and soft emulsions, and mind you this will be different from one paper to the next and maybe even from batch to batch of the same paper. After that it becomes a balancing act to determine the ratio of blue to green light you'll need to achieve a given contrast grade. If you could find the numbers, it wouldn't be too hard to cobble together something yourself. Without the numbers you'll likely be on a quest for the Holy Grail. Oy! The whole thing makes my brain hurt just thinking about it. Better to just get a set of variable contrast filters and be done with it. Either brand is ok, but I'd probably want to go with the Ilford standard now. The Kodak standard was fine for Kodak papers, and they do work with every paper I've tried. But I think most, if not all, paper manufacturers today adhere to the Ilford standard and you might find them easier to work with.
Last edited by fschifano; 04-07-2010 at 06:07 PM. Click to view previous post history.
Well, at this point I am thinking strictly in terms of experimentation.
I will buy a set of contrast filters. Probably Ilford. I just automatically think "Kodak" when I think of film products. It's a function of upbringing.
Once I get them I plan to compare them to the Rosco, Lee and Gamcolor swatchbooks just to see how they measure up.
I wonder if I could put them on my scanner and use my computer to make a comparison.
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...soft emulsion... ...hard emulsion...
Ilford (and Kodak's late Polymax) all use 3 emulsions. The emulsions have the same intrinsic contrast, though different DMax's. All three emulsions are equally sensitive to blue. The 'cyan' and 'green' emulsions are equally sensitive to cyan light. The 'green' emulsion is additionally sensitive to green.
See the application note on VC paper on the Darkroom Automation web site.
(please email me if you are seeing a whacked-out font in the above app note.)
So variable contrast paper works in a way that's analogous to CMY printing. Right?
Whereas printers use cyan, magenta and yellow inks which, when combined, will produce a gamut of different colors, variable contrast papers use emulsions sensitive to blue, green and cyan which, when combined, will produce a gamut of different levels of black.
Therefore, just as it is possible to mix cyan and yellow ink to produce the color red it is also possible to mix amounts of blue, green or cyan light which will produce a certain density on the paper when it is developed. It's only a matter of discovering what colors the emulsions are sensitive to and feeding them what they want to "see" in order to produce a given result.
Yeah... I know... Easier said than done.
But somebody has to know this or else you couldn't use an enlarger with a dichroic color head to print on variable contrast black and white paper. How do enlarger manufacturers figure it out? (Rhetorical question, really.)
If you haven't already guessed, this is the kind of thing that really makes the gears turn inside my head. Even if I don't figure this out to my total satisfaction, there is knowledge gained. Even if I learn nothing else, I now have a better understanding of how variable contrast paper works. Hopefully, that will translate into me being able to produce better results in the darkroom.
No need to do two exposures. Rosco sells CalColor filters in Magenta and Yellow CC grades. So, for a complete set pick up 90M, 60M, 30M, 15M and 15Y, 30Y, 60Y 90Y.
The difference between that set, and the Ilford set is that with the Rosco set, you exposure will be different with each filter. So, I don't know if its worth it to you. I'd just pay the extra $ and get the Ilford set.
At $5.50 per sheet that comes out to $45.00 for a complete set but you would end up with 12 sets of 6 inch filters or 48 sets of 3 inch filters, leaving you with a net cost of about $3.75 or $1.00 per set, respectively.
You can't beat that with a stick!
For my first few times out of the gate I'll do things by the book and get the Ilford filters. Then when I am ready to experiment I'll get the Rosco.