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  1. #11
    Rafal Lukawiecki's Avatar
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    Quote Originally Posted by cliveh View Post
    If you don't have a densitometer, what's wrong with the coin test?
    I don't think you need a densitometer for the Kodak test—the results should be fairly visible across the pre-exposed areas.

    The issue with the coin test is that it does not subject the paper to a pre-exposure under the enlarger. The only exposure the paper gets is the safelight exposure. This way, you are testing the safelight exposure on a sheet of paper that has not crossed the boundary of its inertia. A positive outcome of a coin test is always a positive indication that safelight is not safe, but it will often produce a false negative, in my experience, with safelights that are only slightly unsafe, for example with old safelight filters, some LEDs, and so on. They will not fog the paper, but they will depress contrast just as a pre-exposure of the paper would do, which could be the reason OP is not getting the desired contrast.
    Rafal Lukawiecki
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  2. #12
    MattKing's Avatar
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    Quote Originally Posted by cliveh View Post
    If you don't have a densitometer, what's wrong with the coin test?
    I expect that Rafal is referring to tests which don't involve a slight pre-exposure of the paper when he mentions a "coin test". You can replace the cardboard in the Kodak test with coins and achieve the same result.

    EDIT: he beat me to it!
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  3. #13
    Rafal Lukawiecki's Avatar
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    Quote Originally Posted by MattKing View Post
    I expect that Rafal is referring to tests which don't involve a slight pre-exposure of the paper when he mentions a "coin test". You can replace the cardboard in the Kodak test with coins and achieve the same result.
    That is exactly what I meant, Matt. Thank you for pointing this out, as I should have made it clearer that I was only concerned about safelight tests that skip that important pre-exposure step, which carries the paper over the threshold.

    PS. Also, the cool part about the Kodak safelight test procedure is that it checks both the pre-exposure before and after the safelight exposure, which can yield different results, contrary to intuition. Whoever came up with the test put a lot of thought into a few simple steps.
    Last edited by Rafal Lukawiecki; 12-27-2012 at 02:56 PM. Click to view previous post history. Reason: PS added
    Rafal Lukawiecki
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  4. #14

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    Quote Originally Posted by cliveh View Post
    If you don't have a densitometer, what's wrong with the coin test?
    You don't need a densitometer. The problem with the standard coin test is it doesn't account for the additive effect of safelight and enlarger exposure. The safelight exposure alone might not visibly fog the paper, but it might bring the paper to it's threshold exposure (the same way flashing does), in which case any further exposure under the enlarger, even very minimal exposure through dense highlights, produces tone on the paper. This decreases local contrast, particularly in the upper mid tones and highlights, and can lead to "muddy" looking highlights, even though the safelight didn't produce enough exposure to visibly fog the paper on it's own.

  5. #15
    cliveh's Avatar
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    I understand the wisdom of what Rafal refers in terms of the inertia exposure, but as Matt points out this can still be done with any opaque material after initial exposure. However, I understand where Rafel is coming from and respect this point of view.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  6. #16

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    Multi-contrast papers are designed to produce a grade 2 or 2.5 without any filtration.. If you cannot then you need to develop longer. The problem seems to be with your processing and not with your enlarger.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  7. #17
    Rafal Lukawiecki's Avatar
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    Quote Originally Posted by cliveh View Post
    I understand the wisdom of what Rafal refers in terms of the inertia exposure, but as Matt points out this can still be done with any opaque material after initial exposure. However, I understand where Rafel is coming from and respect this point of view.
    Thank you, Clive, from now on, every time someone asks about safelight tests, I will make sure to be precise in pointing out the matter of the necessary pre-exposure while mentioning a coin test.

    May I just add, that it does make a difference to the outcome of the test when the safelight exposure is made after as opposed to before the enlarger exposure that produces the light tone. The Kodak test takes that into account, but I suppose one could modify a coin test to use two rows of coins and to make two enlarger exposures. It is just that I have never seen a coin test comprehensively include all of those important details, while the Kodak test includes them, and it is concise.
    Rafal Lukawiecki
    See rafal.net | Read rafal.net/articles

  8. #18
    cliveh's Avatar
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    Quote Originally Posted by Rafal Lukawiecki View Post
    Thank you, Clive, from now on, every time someone asks about safelight tests, I will make sure to be precise in pointing out the matter of the necessary pre-exposure while mentioning a coin test.

    May I just add, that it does make a difference to the outcome of the test when the safelight exposure is made after as opposed to before the enlarger exposure that produces the light tone. The Kodak test takes that into account, but I suppose one could modify a coin test to use two rows of coins and to make two enlarger exposures. It is just that I have never seen a coin test comprehensively include all of those important details, while the Kodak test includes them, and it is concise.
    Rafal, you make a very good point, as I had not thought about applying the coin test to before and after. Exposure inertia is an important factor that I overlooked. Thanks.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  9. #19
    bvy
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    Quote Originally Posted by MattKing View Post
    3) it is possible that your desire for high contrast relates mostly to how you see the prints - you may prefer something like the "soot and chalk" look as compared to something with fine tonal gradation. If that is the case, you will need both contrastier negatives and high contrast enlargement filters/settings. I looked at the one enlargement you posted in the APUG gallery and its contrast looks fairly normal. Does it look low in contrast to you?
    Thanks Matt. It's funny because I was trying to decrease contrast with that print. I printed that one using a grade 1.5 filter for 5 seconds. Same film/paper and development, but a few things are different since I created that print:
    1. Different camera (Yashica T5 there)
    2. Different enlarger (I was using the Omega B600 then -- condenser head)
    3. Same safelight but I actually pointed it up at the ceiling until recently. Now it points down and provides more light.

    About the safelight, it's an old Premier Safelight fitted with Kodak OC filter. I don't have a densitometer, but I'll check out the links and try to run a test.

  10. #20
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    I'm not interested in dodging and burning at this point.
    Unless you are totally in control of your scene's illumination, you will likely need dodging and burning.

    The literature suggests that a grade 2 or 3 filter will cover most printing needs, but my results with these always seem to be flat.
    Don't trust "the literature"

    As such, I find myself using the grade 5 filter more often than not.
    Increase negative development by 25%

    I thought grade 5 was for slightly more advanced techniques -- like spilt-grade printing -- and not really to be used by itself.
    You thought wrong.

    Even so, I'm not completely satisfied with my grade 5 prints.
    See above (Increase negative development by 25% and use dodging and burning).


    So I've done some more reading and came across some threads and this link about calibrating your enlarger's color head for variable contrast printing:
    http://www.butzi.net/articles/vcce.htm
    That is a good technique, but Ilford already did it for you if you use Ilford papers (see the chart they put in with all their paper packaging). Realize what is going on with the 'calibration.' It allows you to change contrast and keep your exposure for middle grays constant. It does not make your final prints look any different, it just saves some steps getting the exposure correct.

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