The clarity adjustment is tweaked via an unsharp-mask, more or less. It should be do-able.Originally Posted by Ben Calwell
The clarity adjustment is tweaked via an unsharp-mask, more or less. It should be do-able.
Drew,
No argument from me on any of the above! I wasn't addressing nuances, just trying to shoot down the notion that separate green and blue exposures somehow mystically result in better prints than an all-at-once exposure with a color head or multigrade filter.
You'll also notice that I carefully sidestepped the "how many emulsions?" question, mentioning only "components" that were sensitive to blue and green light. We don't need to get into emulsion design to address the OP's concerns and dispel misconceptions. "Oversimplification" here is just avoiding irrelevant details in order to prevent the discussion from going down unnecessary rabbit holes
FWIW, I usually like the way some VC (both Foma and MCC-110) papers tone when exposed under higher-contrast settings, so I now have a tendency to skimp on development a bit just to be able to print on the more contrasty part(s) of the emulsion.
One thing I avoided mentioning in my previous post, which may make a slight difference between color head/MG filter exposure and using just a blue/green mix is the Hershel effect. It may be that the red component of the former possibly has an effect on the contrast. I don't think it happens much, if at all, but I've never tested, since it would take a lot more sophisticated spectral analysis than I (or most labs!) have access to.
The theory as accepted states that the emulsion doesn't care how it gets its light or in what order. In order to disprove this, one would need to have different results from, say split printing with green first once and blue first the next time, but keeping the times and intensities the same. I don't believe that happens.
At any rate, the point of my post was simply to emphasize that the real advantage of split printing is to be able to print different parts of the image at different contrasts. If you're not doing that, then any old exposure method will get you the same result as any other.
Indeed! The choice of method loops with intent and result in a very mysterious way, feeding back on itself so that the end influences the beginning. Still, while this undoubtedly affects the expressive outcome, the underlying physics doesn't change. Choosing the application of the invariables is part of the creative process. All of these possibilities should be open to those just engaging with the craft, like the OP, which was the purpose of my posts.
Best,
Doremus
These matters came up a while ago and at the time I researched the filters available to (a) pass only blue and (b) block green. It turns out that using blue filters which can be made with very sharp cutoffs (eliminating wavelengths that approach green) is technically better than using magenta filters (subtracting green) since magenta filters have not as sharp a cutoff in those wavelengths that approach green. So blue green enlargers may well achieve a contrastier grade 5. I didn't look at the cutoff frequencies of yellow or green filters but would not be surprised if the similar considerations were true.
Of course this only matters (a) if you have occasion to enlarge using only blue and no green at all or (b) if Bob Carnie's observation, that the order and mix of the various wavelengths, is accurate.
Doremus - on several occasions I've reversed the sequence of which came first, blue or green, on the same image, same development, and couldn't see any visual difference at all. But what is interesting is that some VC papers need a tad of green light to achieve max contrast & full DMax, while certain other papers can do it using blue alone. The main argument against Y vs M filtration is that older colorheads have often lost a degree of filter efficiency due to a certain amount of spalling off of the dichroic coatings. But with a prime set of filters, I can duplicate results all kinds of ways - true additive BG filtration, under the lens 47blue/61green filter split printing with a V54 cold light, YM colorhead subtractive. Just depends what enlarger I find most useful for the particular image. I do everything 4x5 and smaller on a true additive RGB unit, and all my 8x10's in winter using a cold light - why? Because those two particular enlargers fit under an 8 ft ceiling in a nice little room very well insulated, and very easy to keep cozy in winter (and in our cold coastal summers), while my much bigger additive and subtractive 8x10 color enlargers are in a different room with a high ceiling. I don't really think about it much anymore. It's has all become intuitive. But what I have noticed is how much more responsive current premium VC papers are compared to the old ones.
>But what is interesting is that some VC papers need a tad of green light to achieve max contrast & full DMax, while certain other papers can do it using blue alone.
This is interesting. I was aware of the opposite - that the lowest contrast needs a tad of additional blue in order to reach dmax with most papers. But I didn't know something analogous occurs at the opposite end of the contrast range.
Drew,
Yeah, my Chromega heads don't get to the extremes of contrast on either end, but they do the job for 90%+ of my work. For the rest, I've got Wratten #58 and #47 filters. The #47 really gives me a big bump in contrast compared to the 170M on the Chromega E head I use most of the time.
I'm not sure what's functioning with papers that need a bit of green to get to Dmax. Certainly, a print made with both blue and green has more of the emulsion exposed. That would mean, that the prints made on said paper at intermediate contrast settings would have a greater Dmax than those made at the extremes, where less of the overall emulsion gets exposed and subsequently less silver gets developed. Of course, contrast should be appropriately lower. I don't know how adding green would help reach max contrast unless that was directly related to Dmax...
Best,
Doremus
If you have a small part of the silver halide sensible only to green, and another small part sensible only to blue, you need some green light and some blue light to get 100% silver halide exposed. Thus for a maximum Dmax, the copy needs some exposition with an intermediate grade.
Splitgrade makes easy to get the 'grade' where you get maxime value of Dmax without blowing the light parts of the scene. And it's easy to get the optimum value if you expose first the green part and after this the blue part, but it's not mandatory. A friend has made copies professionally with this method in the last 40 years. He's not calling his method splitgrade (perhaps the term was not coined when he learn the technique in UK on the 70')
With some VC papers it seems necessary for full DMax, not for others. I don't have time to figure out why. I just use a token punch of green as needed. If that's an issue, a tad of Farmers Reducer easily solves any highlight muddying issues.
Split grade become popular when multigrade papers came out in the 90's before that we only had graded papers to choose from
, before that it was SPlit Developers, Contrast Masks , Contour Masks and Pencil work to name a few.
Well, I haven't come across papers that seem to need it; I pront mostly on adox mcc and some fomabrom and fomatone and they seem to achieve dmax with only blue light.
I suppose it depends on the silver load and geain orientarion of the different emulsions. Typically stuff that's not very clearly documented.
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