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  1. #21

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    Well, microcontrast is a popular topic of discussion and widely used term, slang or otherwise, here on APUG. Maybe enhanced local contrast would be a better term or more descriptive of the desired effect.

    Peter Gomena

  2. #22

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    It needs to be more specific than local contrast. It is local contrast at very small scales. Local contrast on its own refers simply to the contrast between any adjacent values regardless of size.

  3. #23
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    Micro and macro contrast are terms widely used in the industry and are illustrated in my earlier post. I think changing the terms arbitrarily or misunderstanding them would only confuse people.

    PE

  4. #24

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    I'm easily confused.

    Sorry to muddy the waters. Yes, local contrast on a minute scale. I get the concept, but it's not easy to communicate. I'm sure PE's graphs mean something to the scientists and engineers in the group, but they're a bit over my head.

    Peter Gomena

  5. #25
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    Peter back before digital the photo magazines would run comparative tests of film/developer combinations, and show enlarged sections from images to illustrate the grain, sharpness (definition) etc.

    So you could have a sharp looking image made with a developer like Acutol X which had great initial impact because of the high acutance but lacking very fine detail because of increased grain size, another developer might give excellent fine grain at the expense of slight apparent sharpness (Microdol-X/PerceptoL0 while a third gave a better overall balance of fine grain, sharpness rendering of fine detal, Xtol would fall into this category.

    Ian

  6. #26
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    Peter;

    In the example I posted, the edge effects control apparent sharpness. Due to the nature of emulsions and developers which can interact, edge effects can either cause lower or higher contrast as the size of an object decreases. As size decreases, one goes from the realm of macro contrast to micro contrast. Thus, you might take a picture of an object on 4x5 film and 35mm fim and make the image the same size in a print and have them appear different in contrast because the smaller image may have higher micro contrast.

    PE

  7. #27

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    The concepts of edge effect and micro-contrast would seem to have slightly different nuances. I like
    certain film/dev combinations for enhanced edge effect, like HP5 sheet film in PMK pyro, with expanded development. But after that, I might choose to enhance micro contrast per se, esp in the
    highlights, by use of an unsharp mask. This significantly improves the ability to hold micro contrast
    through the whole scale of the subject, esp in the highlights. But edge effect stays the same unless
    geater diffusion is applied to the mask, which can also be used to fine-tune this very effect. It all
    depends on the degree of the magnification in the print as well. In small format, I find that Pan F
    gives the best edge acutance, provided the scene will accomodate its relative short straight line.

  8. #28
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    I maybe wrong here, but I always thought Rodinal was a high acutance developer, which would work better with films like HP5 as opposed to FP4. Also, surely still bath development will have a greater effect on micro contrast than developer formulation.

    “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. #29

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    It depends on the developer, cliveh. Many high acutance developers are formulated on the basis of controlled exhaustion - ie relative to fine grain developers they contain less developing agent and less preservative. This has a lot to do with how pronounced the edge effects get - particularly when you reduce agitation. Controlled exhaustion also helps explain why diluted fine grain developers do this too. But yes you are correct in saying the development time and agitation intervals (or lack of agitation altogether) play a very important role. If you stand-develop in D76 edge effects are more pronounced than if you agitate normally. However if you stand-develop in a high acutance developer it is possible get such pronounced edge effects that you clearly see contour outlines - even at relatively small enlargement sizes.

  10. #30

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    If you want micro contrast in your actual print, then devlop in PMK and print on graded paper such as Ilford Galerie. Not VC paper.

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