Question about exposure time while multi-grade printing with filters
Certain multigrade filters claim an invariant exposure time between grades, or they provide a factor to calculate the new exposure time at the new contrast grades. Assume this works as it is supposed to.
So I make a test print. If my blacks are both too grey, and my whites are too grey, I suppose you can switch to the next-highest contrast grade and use the same exposure.
Now, suppose I make a print that needs more contrast. I find that the blacks are black enough, but the whites are grey. I switch to the next higher contrast grade. Should I change my exposure?
Suppose my current print has fine whites, but the blacks are too grey. I could increase my exposure to make the blacks blacker, but suppose I judge that that would wash out my highlights. I changed to the next highest contrast grade. Should I change my exposure in this case?
This may be why I've been enjoying the switch to split filter printing .
The constant (invariant) exposure time between grades probably really only applies to the mid-tones.
Usually what I do is try to arrive at a contrast and exposure time that works well with those mid-tones.
Once I get those mid-tones coming out the way I want them, then and only then do I consider what burns or dodges I need to get the highlights and shadows where I want them. I may or may not be be adjusting the contrast filters for those burns and dodges.
For most negatives, the burns and dodges are fairly minor, and frequently don't require any contrast adjustment. For particularly difficult negatives, the printing process can be quite complex.
As you are new to this, I'd suggest starting out with some of the easier negatives. Look for even lighting (preferably somewhat diffused even lighting). As you gain experience, you can move to the tougher negatives, and not be as likely to get frustrated.
One thing to remember. While a nice long range from deepest black shadows to sparkling white highlights is always impressive in a print, it is rarely mandatory, and sometimes it isn't even good.
Good luck, and have fun!
As I understand it, this equal exposure between G.00 and G.3.5 relates only to midtones. Until or unless you start split-grade printing, it might be a better idea to get the highlights as you need them and bump up the contrast incrementally 'til you've got the dark tones you require, adjusting for exposure as necessary (you can do it the other way round if it's easier).
Norman is an island.Time and tide wait for Norman.
I'm glad you said that, Matt. I think sometimes we make printing a technical exercise instead of an artistic one. I have seen many prints that have a really long tonal range, but, IMHO, are too dark and boding for the subject. Others, of course, are beautiful with the full range. Depends on the subject.
Originally Posted by MattKing
To me, it isn't an 'either or' choice but striking a balance where I am comfortable and productive. Everybody has a different level where they like to operate.
Originally Posted by bsdunek
Photography is an art with a very high technical content. Crack open an optics textbook or a copy of Mees for a glimpse of the technology needed to place something in an "artiste's" (or hoi polloi) hands so that he need know no technology. Decrying 'too much technology' seems a bit silly.
There are all sorts of non-artistic diversions in this hobby, gear acquisition stands out to my mind and I am guilty as any of having more stuff than I reasonably need. Some like nothing more than doing film tests. Using technology to quickly get to the visualized print with the least waste seems pretty sane to me.
There aren't many who eschew light meters and do a five frame bracket for every shot. So why do the same in the darkroom? OTOH, sometimes bracketing is the solution.
Last edited by Nicholas Lindan; 02-26-2009 at 01:39 PM. Click to view previous post history.
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Yes, and just which mid-tone it relates to changes when you change the paper you are using. Papers have an equal exposure point between 0.7 to 1.2 OD, (ZV/18% to ZIV-III/shadows), and some are more equal than others.
Originally Posted by Blighty
I tend to add about 10% exp. time for each half grade I dial in.
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The variable contrast filter set I use goes from a grade of -1 (very soft) to 5+ (very hard) in 1/2 step increments. The exposures stay the same for all filters from -1 to 3 1/2 and need to be doubled for the range from 4 to 5+.
The question is what does the term "exposure" refer to; the exposure for the darks, the mid-tones or the highlights? With my filter set the key exposure, the one that stays the same, is the one for the highlights.
I do test strips until I get the highlights right. That determines the number of seconds set on the enlarger timer. If the shadows are too grey I need to select a higher contrast filter; if too black a lower grade filter.
The alternative, pegging exposure for the mid tones is too hard because changing the contrast grade shifts two things simultaneously; the highlights and the shadows! I find it less frustrating to have one thing that stays the same while the other thing is changed up or down.
Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.
Excellent. Which filter set and what paper do you use?
With my filter set the key exposure, the one that stays the same, is the one for the highlights.
The filters are sensitromadensitycorrected so that all filters between 00 and 3.5 require the same exposure and 4-5 require double that. You may have to adjust when moving up in contrast if you didn't nail the midtones in the middle of the curve on your lower contrast print.