acutance vs grain, I don't understand

Discussion in 'B&W: Film, Paper, Chemistry' started by pierods, Apr 10, 2008.

  1. pierods

    pierods Member

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    Hello,

    I was trying to sort out options in choosing film developers, there are so many out there, multiplied by the number of films, it's bewildering...

    I know what grain is. I shot a few rolls of delta 3200, I've seen it.

    Acutance, in my understanding, is the ability of a film to draw un-jagged lines and contours.

    In my understanding, for example, delta 100 draws much sharper lines than hp5.

    I happened to read an article form silvergrain.org that said,

    1. "use fine grain developers for fast films"
    2. "use acutance developers for 100 speed tabular films and panf plus"

    But don't sharp images need fine grain AND acutance? Also, PANF and delta have got very fine grain, so they already draw sharp lines, right?

    To add to the confusion, Kodak says that XTOL has got acutance AND grain, so why are we not closing down this forum and everybody uses XTOL?

    I need help...

    piero
     

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  2. RobC

    RobC Member

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    All film has microscopic grain. It is the speed of the film combined with the developer which affects how the actual grain forms into grain clumps and it is the grain clumps that you see, not the grain. Slow film films tend not to clump so much. Faster films clump more. Fine grain developers tend not to clump grain so much. High activity developers clump grain more.
    Some people make the big mistake of judging how the print will look by looking at the grain in the negative. They tend to like to see an etched look in their negatives. Personally I think that makes the print look too harsh. But that is a subjective consideration so is infact a control for you to use.
    Acutance is the way in which the grain forms the transition from light to dark or dark to light areas. Some film developer combinations make this more pronounced than others. Again this a control for you to use. People worry that a print must have fine grain and good acutance for it to be a good print. But that means they are dictating what defines a good print which is pure nonsense. If you want a print with large grain and poor acutance because it suits your aesthetic, then who is to say that you are wrong.
    People get way to hung up on grain and acutance, especially when they are starting out. Just go with one film and a standard developer and learn it. Then later when you are proficient, experiment with same film and different developers, and then different film and original developer and then other developers. That way you get to learn the different look of the actual print and don't worry about how the neg looks. Follow your instincts and not other peoples and that way you won't turn out to be a clone.
     
  3. John Bragg

    John Bragg Member

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    Hi, Piero.

    Many so called fine grain developers use silver solvents to promote the appearance of fine grain. This hides the true granularity of the film and looses some of the sharpness in the name of smooth fine grain. A true accutance developer contains little or no solvent and will by its nature show more of the true grain of the film with none of this chemical fuzzing. Beutlers formula and Rodinal are true accutance developers and used correctly will provide the highest accutance and honest grain.
    Most developers aim for a balance of properties but if you want the highest accutance, then grain will be more pronounced, that is fact. Finest grain is usually at the cost of a loss in perceived sharpness. To get the best of all worlds try the slowest film in something like Rodinal.

    Regards, John.
     
  4. Sino

    Sino Member

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    Rob, John, does that mean that higher acutance [sharpness] shows less tones in the transition from dark to light in a detail? Can we have that in a picture as an example?

    -Sino.
     
  5. pierods

    pierods Member

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    Yes, could we see examples?
     
  6. arigram

    arigram Member

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    From what I understand it, acutance is how fluffly or sharp the grain is.
    Which makes the grain and the image edges more or less pronounced.
     
  7. RobC

    RobC Member

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    No. I don't use actuance developers.
     
  8. John Bragg

    John Bragg Member

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    Last edited by a moderator: Apr 10, 2008
  9. Steve Roberts

    Steve Roberts Member

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    Of course, much also depends on your enlarging ambitions!

    Steve
     
  10. Dan Henderson

    Dan Henderson Member

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    As Rob said, whether to subdue or enhance the appearance of grain, or whether to produce high acutance negatives with very sharp light/dark transitions is one of the controls the photographer has at his disposal. I happen to really like high acutance, but do not appreciate seeing lots of grain except under certain circumstances. Ilford FP4 film in DiXactol produces these kinds of negatives for me. The slow film has nice, fine grain which is further masked by the staining action of the developer, which does not dissolve the edges off of the grain, thereby increasing apparent sharpness, and developing with minimum agitation produces the edge effects that I enjoy.
     
  11. pierods

    pierods Member

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    All right.

    So we can say that acutance developers render film "truthfully", "as-is", while fine grain developers can be thought as "applying polish" to a negative.

    Right?
     
  12. John Bragg

    John Bragg Member

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    That is somewhat like the truth. Fine grain developers chemically reduce the grain at the cost of reduced percieved sharpness. Accutance developers keep the grain and sharpness intact.

    Regards, John.
     
  13. RobC

    RobC Member

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    WRONG!!!

    No photograph is literal. All photographs are interpretations and its upto you how you interpret the subject and render it.
    You can spend all year talking about grain and acutance if you want, but you won't understand them until you have learnt to control them. And the only way you will do that is by going out and doing some photography and printing it and thereby discovering it for yourself.
     
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  15. pierods

    pierods Member

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    Thanks for all the info.
     
  16. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    If you want to make a comparison for yourself with a single developer, try D-76 or ID-11 stock solution and compare it to the results you get at 1+3 dilution. The solvent effect depends on how much sulfite is in the working solution, and D-76/ID-11 is a solvent developer with a lot of sulfite, so you'll get a strong solvent effect with the developer at full strength, producing fine grain and lower acutance, and much less of a solvent effect at 1+3, producing sharper grain and higher acutance.

    Or if you want to make a very dramatic comparison, try Microdol-X or Perceptol as a fine grain developer and compare it to Rodinal or R09 or Beutler's (I think there's a commercially available version from Moersch or maybe Adox or both) as an acutance developer.

    The single-developer comparison, though, has the advantage of making the most important variable the sulfite concentration in the working solution, and you can usually get the same speed at both dilutions.
     
  17. pierods

    pierods Member

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    Very good suggestion but I need a clarification: what do you mean by speed ?

    As in the description of DD-X on ilford's site:

    "Fine grain developer giving full film speed"

    Film speed is written on the package, what's the developer got to do with it?
     
  18. John Bragg

    John Bragg Member

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    Film speed (as printed on the box) is determined in lab conditions. In practical terms, developer other than that used in the lab test may well change effective speed either up or down.

    Regards, John.
     
  19. Leon

    Leon Member

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    Different developers will affect the notional speed of a film - some will make it faster, some will slow it down. Also affecting this is your own method of developing including temperature, agitation etc etc etc. You may find that by using film box speed works well for you, others dont. With my developer of choice and technique, I tend to be between 1 stop and 2/3 stop slower than box speeds for the detail I want in my negs. Others will be different too - this is why development times and box speeds are always only a starting point. If you're not getting enough detail in your shadows, slow down the film a bit, if you're having to print really soft and still stuggling to get detail in highlights, reduce development time.

    hope that helps
     
    Last edited by a moderator: Apr 10, 2008
  20. dpurdy

    dpurdy Member

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    There is another aspect of accutance developers to consider. To work it has to be a very dilute yet active developer so that it exhausts rapidly. An accutance developer doesn't develop the whole emulsion it developes just the top of it so that sharpness is increased just by the fact that light passing through it goes through a shallower layer of grain. And by agitating less combined with the exhaustion of the developer you get slight more density where areas of more exposure lie next to areas of less exposure and this is accentuated by adding potassium iodide to the developer. The edge affect causes the print to look sharper though in reality it doesn't actually have greater resolution. The dilute nature of an accutance developer causes it to be somewhat compensating.
    http://www.pbase.com/dpurdy/rollei_xenotar__pentax_67
    Every image on this page is processed in Beutlers mostly on Acros but some on Tmax 100

    Dennis
     
  21. fhovie

    fhovie Subscriber

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    Accutance developers generally create "Mackie" lines at the boundaries of dense areas that create a sort of outline that makes an image look sharp. Two ways this can occur is where a weak solvent developer can move silver from a dense area to a boundary like D76 1:3 and another method is with a tanning developer like Pyro anything or Rodinal which will cause the emulsion to physically stop allowing fresh chemistry in at a certain point and then continue to work the boundaries. Stand development promotes this process and there is likely to be a speed increase and an increase in graininess as well. Hi resolution films work against this process - coarse grain films amplify this process. Sharpest appearing images tend to be a little grainy and highest resolution photos tend to be a little soft and mushy looking.
     
  22. Paul Howell

    Paul Howell Member

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    For side by side comparsions you may want to read Thortons' Edge of Darkness. I just bought a copy, and although not my style, a very good read with examples. I tired Dixactol which is based on his formula but found it to have too much gain for my tast. The only developers that I know that has both very fine grain and sharpness are Edwal 12 and 20. Edwal 20 has been off the market for many years and I have not found an exact formula.
     
  23. PhotoJim

    PhotoJim Member

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    You might also want to read Anchell and Troop's Film Development Cookbook. This is an excellent book that will teach you about the trade-offs inherent in black-and-white film development.

    Essentially you are developing for some compromise of acutance, definition, and gradation. Acutance is the appearance of sharpness. Acutance gives more obvious grain but sharper-looking images. Definition is also known as resolution. Surprisingly, resolution and acutance do not go together. You can have high resolution and poor sharpness, and vice versa.

    Gradation is the most difficult of the bunch (to me). It's the tonality of the negative - the relative differences in tones between black and white. The developers that maximize sharpness tend to do so at the expense of gradation (as well as grain, obviously).

    So... getting the best sharpness means you won't necessarily be getting the best gradation. This is why some suboptimal developers (sharpness-wise) can give you the best results - the gradation is improved more than enough to compensate for the loss of sharpness.

    Now, which developer and film should you use? That, my friend, is a question without an answer from us. You will have to find it for yourself. By starting in one place and slowly branching out into other films and developers, you will start to learn what you like.
     
  24. gainer

    gainer Subscriber

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    There is a problem with the artificial edge effects that many photographers enjoy. The edge effects are not scaled with the size of the image. They are chemical, not optical, artifices.
     
  25. Sino

    Sino Member

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    Gainer,

    I didn't quite understand what you mean, could you please explain what you wrote? Cheers,

    -Sino.
     
  26. Tom Hoskinson

    Tom Hoskinson Member

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    According to Michael Briggs, Here is the formula for Edwal-20
    1 liter distilled water
    Gradol 5 grams derivative of para aminophenol
    Sodium Sulfite 90 grams anhydrous [sodium sulfite]
    Diamine-P 10 grams paraphenylenediamine
    Monazol 5 grams photographic glycin

    Source: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=0065dl

    For the Gradol you probably could substitute Rodinal (or 5 grams of p-aminophenol base)
    It appears that Edwal-20 is very heavily loaded with sulfite. D-23 should give a similar look to your negs.

    I suggest using CrawleyÂ’s FX-2 instead