Grain aggregation when processing at high temperatures.

Discussion in 'Black and White' started by matthew_stanton|2, Jul 4, 2003.

  1. Gordon Hutchings claims that using high developing
    temperatures actually inhibits grain aggregation because the
    film spends less time in the developer. When on the odd
    occasion I have used tmax developer @ 24 (1:4) to process Tri-x
    I have found that the grain is remarkably fine, finer than d-76
    stock @ 20 degrees. So I guess I am curious if this theory is
    consistent across the board or only applies to certain developers
    with certain constituents. I get the impression that MQ
    developers should not be used much above 20 degrees
    because the hydroquinone becomes disproportionately active.

    Experience Anyone?
     
  2. That theory may work with modern emulsions such as Kodak TMAX and Ilford Delta Grain films. Maybe also with the new Tri-X. But older emulsions don't like higher temps (but there are fewer of these emulsions every day).
     
  3. 1) What are “higher T”? few degrees above common 20 C is not a problem, otherwise it would be pointed out by the manufacturer.

    2) Is Gordon Hutchings a chemist experienced in chemical kinetics? If not, than such a claim may better fit in gourmet cooking.

    3) It is not a “theory”, it is a MYTH.
     
  4. Can't tell myth from legend, but way back when I used T-Max developer I didn't like it much. Then I noticed that the recommended process was the bold numbers in the chart, and those were for a higher temperature! I tried processing at the recommended temp and seemed to get better results. Can't remember if the grain pattern was more pleasing or what, but I have to assume Kodak made the primary process recommendation something other than 68F for a reason.
     
  5. i'd like to tout matthew's stumblings,

    tri-x and tmax rs is a fine combo when you get it down. real creamery gravery grain but retains lovely tonal seperations... none of that hard-edged vietnam-era dee-seventiesixy docu-golfball grain at all and not nearly as picky as 400 tcrap.

    try it you'll like it,

    me

    p.s. i don't know what 'disproportionately hydroquiwhatsit' means though.
     
  6. Dr. Richard Henry tested exactly this; he found that (for the films and developer tested) the finest grain was obtained at around 70F-72F and that colder or hotter increased graininess. See his _Controls in Black and White Photography_ for all the details.

    That's the only test of such things I'm aware that was done using any semblance of scientific method. I'm sure there were others published in the past but I have no idea of titles or authors.

    I don't know what Hutchings considers to be "high"; if it's say 72F compared to 68F then he and Henry are in agreement while if he's referring to 75F+ then Henry's results contradict him.

    The assertion that less time in a developer inhibits graininess is, so far as I know, unsupported by any experimental results.

    New films are hardened in manufacturing, so they won't suffer the defects that occured with old films in high-temperature processing. Maybe that's what Hutching was referring to.
     
  7. Isn't TMAX a hydroquinone developer anyways?
     
  8. Yes I think it is actually Phenidone/hydroquinone now that you
    mention it, hmmm.

    Tribblet, to clarify, I meant that perhaps the superadditive effect
    between Metol and Hydroquinone becomes imbalanced at
    higher temperatures. I believe this is due to hydroquinone
    exhibiting a greater reaction to increased temperature than metol
    does. But I may well be wrong.

    So I assume that the unexpected difference I found between
    these results is more to do with developer and not temperature.
    I would have expected tmax to be noticably grainier at the same
    contrast index..... not so.
     

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