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  1. #1
    pstake's Avatar
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    Rodinal dilution and acutance

    I have heard it both ways, that higher dilution (i.e.: 1+50) = higher acutance; and that lower dilution (i.e. 1+25) = higher acutance.

    Does anyone know which is correct?

  2. #2
    cliveh's Avatar
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    Quote Originally Posted by pstake View Post
    I have heard it both ways, that higher dilution (i.e.: 1+50) = higher acutance; and that lower dilution (i.e. 1+25) = higher acutance.

    Does anyone know which is correct?
    Rodinal is a high acutance developer and I would suggest the only difference in dilution strength is that the longer times provide greater possibilities for still bath development, but doubt if this makes much difference.

    “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

  3. #3
    ruilourosa's Avatar
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    more of a compensation effect, although semi stand and stand development with 1:100 do indeed increase adjacency effects and makes mackie lines broader and deeper!
    vive la resistance!

  4. #4

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    Rodinal at 1:25, especially using Agfa's recommended development times, results in contrasty negatives. One can mistake high contrast for accutance. A properly developed negative using dilutions higher than 1:50 (1:75 and 1:100) produce edge effects enhancing sharpness. The effect is visible but not dramatic. One could argue changing film from Tri-X to FP-4 or T-Max 100 is nearly as effective.
    RJ

  5. #5
    pstake's Avatar
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    Quote Originally Posted by Richard Jepsen View Post
    Rodinal at 1:25, especially using Agfa's recommended development times, results in contrasty negatives. One can mistake high contrast for accutance. A properly developed negative using dilutions higher than 1:50 (1:75 and 1:100) produce edge effects enhancing sharpness. The effect is visible but not dramatic. One could argue changing film from Tri-X to FP-4 or T-Max 100 is nearly as effective.
    Thanks for this. Thanks to everyone else, too. Good information.

  6. #6

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    +1 on pstake's reply.
    Long development times with high dilutions (a favorite is 1:100, from 20 minutes and up depending on agitation schemes - stand, semi-stand, etc) yield acutance effects.
    The smaller the format size, the more they are seen in the print.
    You can find more on this forum by searching for "stand" and "semi-stand", many threads gone over the dam.

  7. #7
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    Quote Originally Posted by George Collier View Post
    +1 on pstake's reply.
    Long development times with high dilutions (a favorite is 1:100, from 20 minutes and up depending on agitation schemes - stand, semi-stand, etc) yield acutance effects.
    The smaller the format size, the more they are seen in the print.
    You can find more on this forum by searching for "stand" and "semi-stand", many threads gone over the dam.
    One more question. What is the difference between "stand" and "semi-stand," or is it the same thing?

  8. #8

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    Stand development is a principle that involves initial agitation (longer than normal, some recommend up to 2 minutes), then the tank sits for a much longer than normal time. (not for open tray schemes) Semi stand is similar at the beginning, but introduces agitation at intervals of 3 - 5 minutes, to ensure uniform development in even (eg - sky) areas.
    I have left a lot out here - use the search engine for this forum, and enter the two terms "stand" and "semi-stand". you'll find lots to read, opinion and fact both. People have widely varied experiences with this method.



 

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