Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,523   Posts: 1,572,298   Online: 839
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 24
  1. #1

    Join Date
    Mar 2009
    Location
    NC
    Shooter
    Medium Format
    Posts
    81

    Agitation Aggravation...

    Ok That was my best attempt at a catchy thread title. lol anyways down to business.

    I have read probably 100 different threads on "proper agitation." I think there are about 9-10 different schools of thought. Mine is pretty simple 10-15 seconds of "gentle" agitation the first minute and then 5 seconds of the same each subsequent minute. Easy enough but here is where my question comes.

    I have been reading "The Negative" and it talks about different kinds of agitation and on here people talk about what LACK of agitation does. So I decided to do a little test. On a roll of Fomapan 100 I spent taking photos of mostly low contrast subjects with two images that included some overcast skies with different shades and shapes in the clouds. Am I right in thinking that less agitation will cause some "blocking" in the highlights and PREVENT them from being over-developed thus producing more details in the clouds??

    Reason I mentioned shooting a less contrasty scenes was because I also under-developed to "contract" the zones if you will. I shoot my Foma at box speed developed in Rodinal 1+75 at 7:20. I think Digital truth says 1+50 at 7 minutes. My agitation was gentle for 10 seconds then 5 seconds until the 3 min mark. Then NO agitation for 2 minutes, on the 6th min there was a swirl of the tank and then none for the remaining 1:20.

    My test results wont be able to be completely looked over until the negatives are completely dry and I get a scanner to look over them more closely. I did notice that I could make out different tones in the clouds but really cant tell unless I shoot the same "scenes" with more or less agitation.

    So what is it ladies and gents? Less agitation cause "blocking" giving you decent tonal range in bright scenes like clouds??


    ~mike

  2. #2

    Join Date
    Mar 2005
    Location
    Central NC
    Shooter
    4x5 Format
    Posts
    444
    Quote Originally Posted by mr. mohaupt View Post
    Am I right in thinking that less agitation will cause some "blocking" in the highlights and PREVENT them from being over-developed thus producing more details in the clouds?
    I wouldn't put it that way. If all other things are equal and the only parameter changed is that you reduced agitation, then you'll get a negative with a lower gamma (contrast index) and lower Dmax. If your image was getting up into the film/developer's shoulder region, and this decrease in agitation dragged the highlights down the response curve away from the shoulder, then you could get some more highlight separation. But increased tonal separation isn't at all the same as "more detail." The detail you had at exposure is the detail you have -- your process can't create detail.
    Bruce Watson
    AchromaticArts.com

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,382
    Images
    65
    Well, there is another effect depending on film and developer. At low agitation, you tend to see more edge effects around developing images. This can be extreme or mild but can lead to enhanced sharpness. On the extreme edge, you get an effect called "bromide drag" in which the image becomes smeared due to bromide released and which is not evenly redistributed by even agitation.

    So, there are pros and cons and techniques to master in using "agitation".

    PE

  4. #4

    Join Date
    Mar 2009
    Location
    NC
    Shooter
    Medium Format
    Posts
    81
    Quote Originally Posted by Bruce Watson View Post
    I wouldn't put it that way. If all other things are equal and the only parameter changed is that you reduced agitation, then you'll get a negative with a lower gamma (contrast index) and lower Dmax. If your image was getting up into the film/developer's shoulder region, and this decrease in agitation dragged the highlights down the response curve away from the shoulder, then you could get some more highlight separation. But increased tonal separation isn't at all the same as "more detail." The detail you had at exposure is the detail you have -- your process can't create detail.
    Hey Bruce I am in Central NC as well! Nice.

    So what you are saying is more like "muddyed" highlights?

    PE
    Call me crazy but around the edges I have seen nothing unusual. I read a thread about a guy who was getting sever over development near the edges but in the last say 10 rolls I have developed in the last month and a half I have not seen anything like that. Guess I am agitating the "right" amount?

    You also mentioned increase/decrease in sharpness. I take it you mean acuteness? And increase or decrease in agitation increases or decreases sharpness? I thought acuteness was a function of the film only?

    ~m

  5. #5

    Join Date
    Mar 2005
    Location
    Central NC
    Shooter
    4x5 Format
    Posts
    444
    Quote Originally Posted by Photo Engineer View Post
    Well, there is another effect depending on film and developer. At low agitation, you tend to see more edge effects around developing images. This can be extreme or mild but can lead to enhanced sharpness.
    PE, I've heard this often but I've never found any supporting science in the literature. Of course the massive Haist set is only available at my local university library so spending much time with it is problematic. So... can you give me any pointers to where I might find research into the effects of agitation on the creating of edge effects (that is, I think, the formation of Mackie lines, yes?) I want to learn more about it but can't seem to put my hands on the actual science behind it.
    Bruce Watson
    AchromaticArts.com

  6. #6

    Join Date
    Mar 2005
    Location
    Central NC
    Shooter
    4x5 Format
    Posts
    444
    Quote Originally Posted by mr. mohaupt View Post
    So what you are saying is more like "muddyed" highlights?
    That's not what I said. I couldn't say that without knowing what you intended to do with the film. Different printing techniques need different contrast and Dmax. So one person's "muddy" might be another person's "Crystal Clear."
    Bruce Watson
    AchromaticArts.com

  7. #7
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    This may sound off topic, but I don't thik so.

    Young man, lost. Sees elderly stranger with violin case. Thinks "He'll surely know." Says, "Sir, can you tell me how to get to Carnegie Hall?" Old man says "Practise, practise, practise."
    Gadget Gainer

  8. #8
    Guillaume Zuili's Avatar
    Join Date
    Aug 2005
    Location
    Los Angeles & Paris
    Shooter
    Multi Format
    Posts
    2,639
    Images
    216
    Quote Originally Posted by gainer View Post
    This may sound off topic, but I don't thik so.

    Young man, lost. Sees elderly stranger with violin case. Thinks "He'll surely know." Says, "Sir, can you tell me how to get to Carnegie Hall?" Old man says "Practise, practise, practise."
    Sweet !
    :-)

  9. #9

    Join Date
    Jun 2003
    Shooter
    Multi Format
    Posts
    16,880
    Images
    27
    Quote Originally Posted by gainer View Post
    This may sound off topic, but I don't thik so.

    Young man, lost. Sees elderly stranger with violin case. Thinks "He'll surely know." Says, "Sir, can you tell me how to get to Carnegie Hall?" Old man says "Practise, practise, practise."

    thank you !

    john

  10. #10
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,382
    Images
    65
    Edge effects and bromide drag depend on film and developer and so I cannot give any specific pointers.

    As agitation decreases, edge effects degenerate into drag effects caused by gravity dragging the bromide downward in the developer due to density effects.

    Edge effects have been described elsewhere, but basically they decrease density in the center of a dark image and increase density at the edges, with a defined "halo" around the edge. This gives the perception of increased sharpness. Drag simply causes smeared and altered density effects across the area of the image to the extent that you see it. It is usually worse at the sprocket holes on 35mm film.

    If you don't see it, then your film/developer combination is likely insensitive to the agitation you have chosen, but if you do, then it is. This is a hard one to judge. I have seen films and papers with huge effects and others with none. It depends on bromide in the developer, ioidide in the film and a variety of other things that really have no meaning here except as related to what you see, and that is more important than the mole% of iodide.

    PE

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin