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  1. #11
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    Quote Originally Posted by BetterSense View Post
    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?
    There's way's to test the speed matching (i.e., the ability to change contrast filters and still use the same printing exposure time) claims made by manufacturers. If you care to take it that far, then I would suggest Steve Anchell's The Variable Contrast Printing Manual; I believe all you'll need is a 21-step density tablet. There's also a good section in there about split grade printing; single filter printing, and multiple filter printing.

  2. #12
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    One thing not mentioned here is that there are two ways to design a VC paper. One can take advantage of being rather invariant to printing filter(s) particularly in the mid tones. But, another method of making a VC paper gives vastly different speeds at each contrast grade.

    The first method is more difficult than the second and therefore, you will find that top grade papers are close to being invariant with a small filter factor, but papers from 3rd tier manufacturers may vary by several stops as contrast grade varies.

    This will generally be the case with graded papers from the same companies.

    The reason is that top grade companies will design an emulsion for each grade and tailor the speeds to match, but 3rd tier companies with less R&D money will opt to use 1 emulsion and force fit contrast allowing speed to wander all over. Generally, speed goes up with contrast in these cases.

    So, result also depends on paper.

    PE

  3. #13
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    Wonderful information. Thank you everybody.

  4. #14

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    Of course, you might consider doing you own tests to define the "speeds" of your own filters-either in sets, or individually. Steve Anchell's book gives good instructions for making such determinations without the use of a densitometer, and Ralph Lambrecht in his legendary and encylopedic Way Beyond Monochrome also presents a bit more technical approach to making such "filter speed" determinations. I also believe that Nicholas presents, on his web site ( Darkroom Automation ), detailed instructions for making " tone test strips" ( my words, not his )so that various tones can be easily obtained with each grade with each paper you use. There are methods to proceed should you desire, and have both the inclination and time.

    OTOH, I believe that Maris and blightly make an excellent point, and their method is the way I am currently working as well. It is the "method" taught in the wonderful book by Carson Graves. It should be pointed out, of course, that when one changes grades of paper so that the blacks are "correct", that the exposure for the highlights also changes. However, you tell us that your filter set is speed matched for the highlights, and so such highlight exposure changes are not likely to be difficult to find. Note that if the highlights and the shadows are to your liking that the intermediate tones will "fall into place" ( as explained by Mr. Graves ).
    Last edited by Mahler_one; 02-26-2009 at 08:25 PM. Click to view previous post history. Reason: Information added

  5. #15

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    Thus, if I might, let's consider one of your questions:

    <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?>

    In the scenario envisioned by some of us, and as taught by Carson Graves, if the blacks are too grey you do not increase your exposure to make the blacks darker. As you suspected, you then reach for your filter set, and increase the contrast which will make the shadows to your liking. As Mr. Graves has taught and written, the other intermediate tones will fall into place. Since your filters are speed matched for the highlights, your exposure for the highlights will be correct. If for some reason the highlights are NOT correctly exposed, then small changes in the highlight exposure should be considered. In the scenario we espouse, always expose first for the most important highlights, then examine the print. Modify the contrast based upon the shadows....too black, decrease the contrast grade; too grey, increase the contrast grade. The nice thing about VC papers is that the contrast grades might be almost infinitely variable ( depending upon your filters, your paper, your developer ) by using small changes in the settings of your filters. Thus, you might be able to dial in a filter grade of 2 3/4 if 2 1/4 isn't to your liking and the shadows aren't quite right to your eyes. As needed, modify the exposure slighlty so that the highlights in each print are the same, or very similar to the highlights in your test strip, or first print. Those of us who like to experiment with graded paper can also try to find some intermediate grades, but we must use different developing times, or developers, or combinations of both ( ! ) in order to more finally tune the contrast we seek. Frankly, as I write about the subject, using VC paper appears to be much easier!

    I sincerely hope that we all have been of a little help to you, and I wish you much success in your endeavors.

    Ed

  6. #16

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    Great point, as usual, made by PE above. PE...how do you find all of this arcane information? So THAT'S why the exposure from about grade 1 to 3 on my brand name papers isn't all that different! Thanks.

    Ed

  7. #17
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    Quote Originally Posted by Mahler_one View Post
    Great point, as usual, made by PE above. PE...how do you find all of this arcane information? So THAT'S why the exposure from about grade 1 to 3 on my brand name papers isn't all that different! Thanks.

    Ed
    My comments were based on actually making and coating the emulsions and papers.

    So, to me, it was not arcane. It was all in a days (paid) work.

    PE

  8. #18
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    Quote Originally Posted by BetterSense View Post
    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?

    Equal exposure time for filters aims for the paper's ISO speed point, which is at 0.6 plus b+f density. This is lighter than Zone V, which has a density of 0.75, but the whole idea of not changing the exposure time when changing contrast only works with calibrated enlarger setups anyway. And even then, it's safe to assume that exposure needs to be slightly adjusted after a contrast change.

    For most prints, I teststrip the exposure for the highlights and adjust the shadows with contrast. If you get significant highlights and shadows on one test strip, you can determine exposure and contrast in one go.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #19
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    ExpCompCntrstChangeEd2.pdf
    Quote Originally Posted by MattKing View Post
    Bettersense:

    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!

    Matt
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  10. #20
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    [QUOTE=MattKing;759149]Bettersense:

    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.QUOTE]

    yes, it applies to yhe speedpoint of the ppaper st roughly 0.6 density.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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