Split Printing

[Maine-iac]

Larry,

I know that split filter vs. single exposure seems to work better for people. But I haven't been able to explain why. Do you know how to explain what's happening differently when two extreme filter exposures are used instead of one in the middle. Using say the Ilford 3 emulsion multigrade paper. I'm looking for an "Idiot's" guide to explain this to me.

Chuck

I'm neither a chemist nor a sensitometrist; I'm a word person, so I don't know if my explanation would pass muster with those who are much more into the science of it. So take this with the appropriate grain of sodium chloride.

As I understand it, the emulsion of VC paper is really two emulsions: each sensitive to a different color of light. Together, depending on the color of light used in the exposure, they accommodate a range of contrast/density comparable to graded papers.

They work perfectly well with single contrast filters (here the "grades" are the different filters, e.g. 0-5, rather than in the paper. So the color of the light transmitted by a #3 filter (which contains more magenta) will be different from the color of a #1 filter (which contains more yellow). Same with a dichroic head. You can dial in, e.g., 30M and 20Y, expose for, say, 14 seconds, and your print will look like whatever comparable graded paper is the equivalent.

You could fine tune your print, after the basic 30M/20Y 14-second exposure, by then giving extra M or extra Y to some parts during burning in.

However, by giving one exposure at full Yellow and one at full M (individual times to be arrived at by stepped test prints of each color (for each brand of paper), you are, in effect (and this is where my explanation probably won't satisfy the sensitometrists among us), calling forth all that the negative permits and all the emulsion will give in response to each of those colors of light. Some negatives, of course, will not have a full range of tones, or be somewhat over or under-exposed, and will not, at the basic exposure, give the fully detailed highlights or fully textured shadows that you want, so you can fine-tune by burning and/or dodging with one color or the other. But you're simply building on a solid base that's already called out everything the negative/paper emulsion/developer will give you.

All I can say is that the first time I tried this and got a near-perfect print on my first try (after the test strips), I nearly fell over. After my initial surprise, and after comparing them with other prints of the same negatives on the same paper, but made with single-color exposures, I could see subtle, but really visible differences in the depth of shadow detail, the delicacy of highlight detail and a kind of luminous quality to the print that wasn't there in the single-color exposures. I think the luminosity of a particular print tone is what is meant by "local contrast." It's not the contrast between different tones, but the micro-contrast within a single tone.

I still occasionally use techniques like bleaching local areas, but this is either a purely aesthetic decision or due to a troublesome negative that I under-exposed or over-developed or something. It's amazing how many fewer heroic measures are necessary to get a fine print with the split-filter/divided development technique.

So there you have my non-scientific explanation. Hope it helps, but don't worry too much about the theory; just experiment and enjoy.

Larry

 

[Maine-iac]

My take is that you are splitting the exposure decision in to two (partially) separate time sections: one for the highlights and one for the shadows. No guesswork is involved.

Yep.

The use of the two test strips eliminates all this faffing about - you nail the time and contrast in two strips. However, if the shot is of low contrast there may not be sufficient shadow or highlight detail to hang your times on, in which case you may have to fall back on previous methods.

I've never experienced this. Any negative I've shot is amenable to the split-filter technique, even bad negatives. At worst, when I have a weird negative, or an "abnormal" subject contrast, or whatever, I have to do a couple more test strips if the first work print reveals major printing problems.

Happened the other night, in fact. I had taken some snow scenes on 6X7 roll film under pretty bright, backlit, flare-y conditions, and had bracketed exposures,etc.

The neg I thought might be the best to print, turned out not to be. When the highlights were right, the contrast of the shadows was very weak, and vice-versa. It was enough to make me a believer in the old dictum, "avoid backlighting like the plague." Anyway, I had to do a lot of burning and dodging using different Y or M exposures on quite specific parts of the print to get the effect I wanted, and ended up going through about 8-10 sheets of paper before I was satisfied. But that was a rare instance. Usually I have what I want on either the 3rd or 4th sheet, and not infrequently on the second.

Larry

 

[lee]

Larry,

Your experience wrt split filter printing mirrors my own experience. It is so easy to get to the good work print I see no reason not to use this excellent technique. I did take a few secessions to "think it out", but after I got it I got it.

lee\c

 

[titrisol]

I haven't tested split development after split printing but it seems to make a lot of sense.
Are you using water-bath dev or hard/soft combo?

 

[Les McLean]

The two coats of emulsion explanation is old technology. Ilford VC paper is now coated in one emulsion that is made up of three different emulsion mixes and mixed at the time of coating. I have been reliably informed by the person in Ilford who designed Warmtone that the idea that two emulsions sensitive to different colours of light is the reason that split grade works is not entirely accurate.

My own explanation as to why it works for me is based on the negative densities and controling the hard and soft exposures to mix the two grades to achieve the tonality required, ie more soft , less hard will produce more rounded tones whereas more hard less soft will produce a more brittle range of tones. A black produced with more hard filtration will appear darker that a black with more soft, this is simply because there is more contrast present.
Therein lies the real benefit of split grade printing for either hard or soft filtration can be dodged to change local contrast in a way that cannot be achieved by any other process. In a nutshell I control my contrast by careful control of exposure.

 

[Maine-iac]

I haven't tested split development after split printing but it seems to make a lot of sense.
Are you using water-bath dev or hard/soft combo?

See my post in the Chemistry Recipes section on Divided B&W Paper Developers.
The answers to your question are there.

Larry

 

[Maine-iac]

The two coats of emulsion explanation is old technology. Ilford VC paper is now coated in one emulsion that is made up of three different emulsion mixes and mixed at the time of coating. I have been reliably informed by the person in Ilford who designed Warmtone that the idea that two emulsions sensitive to different colours of light is the reason that split grade works is not entirely accurate.

Thanks for this correction, Les. I was sure that there was someone out there who knew more about the emulsion part than me. Whatever the sensonometric/chemical science, I'm just glad it works and that someone turned me on to it many years ago. It may have even been in an old Camera 35 article or something like that, which tells you how long ago it was.

Larry