Exact differences between Rodinal 1:25, 1:50, 1:100

Discussion in 'Black and White' started by dagata, May 27, 2004.

  1. I've searched all the threads but haven't come up with a straight
    answer on this: what differences do you perceive when diluting
    Rodinal 1:25, 1:50 or 1:100 and using it with Tri-X rated at 400
    (35mm)? Thanks.
  2. The more you dilute a developer, the more compensation occurs, which can be very helpful in high contrast situations.
  3. I can see the compensation sure worked in that photo.

    tim in san jose
  4. Dino,

    At the outset, let me say that I have not tested or used Tri-X with
    Rodinal in many years but I recently did calibrate FP4+ sheet film
    in Rodinal diluted 1+25, 1+50, 1+75 and 1+100 using the Phil
    Davis BTZS testing technique with calibrated step-wedge and

    My objective was to determine the effectiveness of Agfa's
    suggestion that contrast be controlled by dilution as a useful
    tool. I also wished to investigate Minor White's suggestion that
    once the Subject Brightness Range was determined that
    mid-tone rendition could be altered by developer dilution.
    [Perhaps another thing to determine was whether shorter time
    rocking a dish in the dark might be feasible.]

    In plotting the curves of the various dilutions my suspicions
    regarding Agfa's suggestion were confirmed. My general dilution
    for Rodinal has been 1+100 for years and given the harshness
    of Australian summertime light this has served me well.

    At a dilution of 1+100 considerable contraction is possible but
    expansion just blows the dev time way out from 13:28 to more
    than 30 minutes for N+1.

    At 1+75 expansion to N+1 is easier and so the pattern continues
    until at 1+25 the dev time is so short that contraction could not be
    achived practically but considerable expansion to N+3 presents
    no problem.

    So, yes, the various dilutions do have a useful effect in their
    ability to control brightness ranges of varying length.

    As for the influence of dilution upon acutance I was hardly able to
    tell. I exclusively use 8x10 and contact print — ALL the negs
    displayed superb definition and, as you'd expect, grain is not an

    The negs developed at 1+100 did display more 'compensation'
    effect than any others — the shadows did display greater
    separation, they were more 'open'. Otherwise local contrast was
    a little smoother until I got to 1+25.

    I suggest you make your own comparisons in the format(s) of
    your choice and the emulsion of your choice. As a starter I can
    provide the following as a starting point for NORMAL
    development at 70º with continuous agitation for the first 30
    seconds and then five seconds agitation each minute for the
    remainder to give a neg optimised for a CONTACT PRINT on
    Ilford Multigrade filter 2.5 and MGIV FB paper.

    1+100 = 13:28 - E.I. = 100 for FP4+

    1+75 = 11:26 - E.I. = 100 for FP4+

    1+50 = 7:00 - E.I. = 100 for FP4+

    1+25 = 5:06 - E.I. = 100 for FP4+
  5. Jay -- there is a lot of compensation going on in your posted shot. If you used 1+100 for what you’ve posted then lets see what 1+200 looks like next time -- OK?
    Dino -- the ONLY thing everyone will notice, guaranteed , is their bottle of Rodinal lasts 4 times as long when using 1+100 as it does when using 1+25. After that the differences for many are much more subtle as it’s really all about what you look for in a print and how good a printer you are ;o).
    Disclaimer: The following holds true for many but not all films. I'm writing it with Agfa APX 100 & the old APX 400 in mind (I have not tried the new APX 400). In addition I do not use Rodinal with many other emulsions (usually because of Rodinal’s inherent loss of film speed) -- I use XTOL at 1+3 for new emulsions such as the Deltas and I use D76 for TriX:
    Jay mentioned that Rodinal at 1+100 is a compensating developer, that’s true. (I should mention that not all developers are compensating at high dilutions). Along with compensation – which usually helps make your print making easier – less dodging & burning are necessary, I notice increased edge sharpness / acutance with 1+100. Tonality at 1+100 is as good or better at then at 1+25. Grain is larger at 1+100 then at 1+25 so much so that many find 35mm APX 400 & TriX grain objectionable. Having said that I can only say that the grain while large is the best lookin’ grain I‘ve ever seen; it’s sharp, sharp, sharp!
    Another Disclaimer here: Agfa used to insist that a minimum 3 mls of Rodinal stock be used for each roll of 35 mm or 120 film. That also meant 6 mls of stock for a roll of 220 film. Agfa has changed that. They now insist that a minimum of 5 mls of Rodinal stock (in some posts I’ve seen it stated as 10 mls of Rodinal stock) must be used no mater what the working solutions dilution! I believe the change to 5 or 10 mls came about because people did not / could not measure their 3 mls of stock properly / accurately! It's essential that you use a medical syringe or a pipette to measure your Rodinal stock.
    And agitation: I believe (others whose opinions I respect do not) that agitation plays a part in 1+100 Rodinal processing. I feel that a minimal amount of agitation ensures maximum acutance. John Hicks takes a different stance. He claims this not to be true; that maximum acutance can also be achieved with roller processing. I realize that I should test this but I figure why bother -- what I’m doing, 10 to 15 gentle twisting inversions during the first minute then one gentle twisting inversion every additional minute -- works, why fix it?
    And to close here is a recent shot using APX 100 & Rodinal 1+100. Looks good on a monitor, looks even better as a conventional wet darkroom 8x10.
    It’s got all the dilute Rodinal and APX film characteristics -- it's sharp, tonal & very easy to print.
  6. Walter,

    Your experience is amazing. You've put into words everything I've felt about the visual characteristics of rodinal and could never express.

    Thank you.
  7. With Tri-X at 400 I haven't seen any differences between negatives developed in Rodinal at 1:25 or 1:50 and normal agitation. I don't recall having tried it at 1:100, mostly because of the long development required.

    The last statement may seem contradictory, however, considering that I do use Rodinal at 1:200 on Tri-X. But this is for stand development, usually two-hours, and I'm not babysitting the tank, agitating it. With stand development in very dilute Rodinal I do see a stronger compensating effect that I don't see in less dilute solutions and normal agitation.

    So for the sake of economy, with Tri-X I use Rodinal at 1:50 for normal purposes. For stand development at 1:200.
  8. Thanks, everyone. This is 1:25--was too lazy to dilute 1:50; very
    little agitation.
  9. As a Rodinal user of some twenty years standing I have to say that I use the higher dilution partly for the increased compensation but most notably to get a longer development time. I like development times of 8-10 minutes so that I can get finer control. I can't say that I've noticed any really significant differences between films developed at 1:25 or 1:50 in terms of grain etc. But something tells me there should be a difference. Where grain growth occurs in chemical reaction, the slower the grain growth then the longer the filaments - but whether this would be visible is a moot point. I am currently running trials with D23 and when comparing Delta 100 processed in this versus Rodinal I noticed a difference in the nature of the density in the negs. The negs processed in Rodinal has a slight translucency to them whereas those processed in D23 were more purely transparent. What the significance of this is I don't know. Rodinal has a particular tonality (noted by Bob Scwalberg among others) and I am of the same mind as Bob in that I favour developers with a single developing agent, hence Rodinal (para-aminophenol) and D23 (metol). But back to the question - I normally rate Tri-X (400 TX) at 160 and dev in Rodinal, 1:50, 20 C, 9.5 minutes.
  10. I'm having a difficult time focusing on the words in this thread.
  11. I can't say that I've noticed any really significant differences between films developed at 1:25 or 1:50 in terms of grain etc. But something tells me there should be a difference.
    Well I think there is a difference in grain appearance, but it's subtle. To get more radical grain differences, switching to another developer would be the best bet. Of course grain also depends much on the film used.
    Some good points here, so I won't start talking about compensation etc. We're getting to the fine points of development, so having a consistent process starts to be more important than the subtle differences achieved by some dilution alterations (otoh, I think trying Rodinal at different dilutions can be instructive...)

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