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  1. #201
    wiltw's Avatar
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    Quote Originally Posted by Ian Grant View Post
    It was pointed out in another thread that he made his last important negative in 1949, according to his biographer

    Ian
    And your point is...? The fact that the Zone System was written around contrast enhancement or reduction during film processing does not get rendered as totally immaterial with modern films, even if Ansel quit doing his own processing.
    Last edited by wiltw; 07-21-2010 at 01:35 AM. Click to view previous post history.

  2. #202
    Wade D's Avatar
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    If acetic acid is not diluted enough (wrong proportions) it can result in pinholes in the negatives. I found this out the hard way 40+ years ago. Since then I have used water only for film which has worked well. Recently, though, I have been using a citric acid stop bath for prints which smells much nicer than acetic acid. I may try it on film as well.

  3. #203
    Ian Grant's Avatar
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    Quote Originally Posted by wiltw View Post
    And your point is...? The fact that the Zone System was written around contrast enhancement or reduction during film processing does not get rendered as totally immaterial with modern films, even if Ansel quit doing his own processing.

    He was using older thick emulsions, modern thin film emulsions don't really respond to water bath development. To control highlights with water bath development the negative is placed in water before the high lights have fully developed to hold them back. But we are talking about giving full development.

    But after a rinse modern thin emulsion negatives have little developer left in them anyway.

    Ian
    Last edited by Ian Grant; 07-21-2010 at 01:54 AM. Click to view previous post history. Reason: add

  4. #204
    wiltw's Avatar
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    While Adams did later withdraw conventional water bath technique (used in a famous photo in 1936) as no longer applicable to modern emulsions, due to streaking, there is a modified procedure which advocates (The film developing cookbook By Stephen G. Anchell, Bill Troop) the water bath to affect contrast of the negative without the streaking issues.

  5. #205
    Ian Grant's Avatar
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    Quote Originally Posted by wiltw View Post
    While Adams did later withdraw conventional water bath technique (used in a famous photo in 1936) as no longer applicable to modern emulsions, due to streaking, there is a modified procedure which advocates (The film developing cookbook By Stephen G. Anchell, Bill Troop) the water bath to affect contrast of the negative without the streaking issues.
    Using an alkali bath (Sodium Sulphite) instead of water will have other effects, despite the pH the sulphite will slow the rate of diffusion initially.

    But as you yourself said you've used water as instead of stop abath for nearly 50 years so you know it works

    Ian

  6. #206
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    Well, here are some additional comments on these recent posts.

    1. You don't have to diffuse the acid through the emulsion, only the proton, which is the smallest of all ions. I have seen the rate of pH drop when using acid on alkaline films. It is virtually instantaneous on a wet film. Today's thinner films make acidification very rapid. How was this tested? Among other things we coated /gel/dummy emulsion/indicator dye/support and then looked at the spectrum of the indicator dye vs time. We also used a surface pH meter but that was too slow!

    2. Pinholes would only be possible with Carbonate developers, poorly hardened film or thick film. This effect has not been demonstrated since the 50s and even then an acid stop was still recommended. It was also only seen in deep tank processing, not tray or tank developing.

    3. If you use a rinse after development, it must be done with running water not with standing water. If you can, check the rinse water pH sometime if you are using a standing rinse. You will see that it is quite alkaline and it will vary depending on what you put into it in terms of film, paper and developer that is carried over. For example, D8, D11 or D19 will generally give you more adverse effects than D76 or Dektol. Films with development times less than about 5 minutes will show more effect than those with 7 minutes or greater. There is a hazy area in between.

    4. A true stop also contains Sulfite, although plain acid will do. This Sulfite helps prevent stain formation and form a more soluble version of HQ if it should be oxidized to the Quinone form.

    PE

  7. #207
    ruilourosa's Avatar
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    with a running water stop bath for at least one minute i never saw problems, even with alkaline stop bath, although is a bit on the strech line to use just a change of water... but if you use an acidic fixer maybe you won´t have problems, i have saw people not using stop bath and having no problems, but...
    vive la resistance!

  8. #208
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    So far this thread is over run with testimonials.
    Kind of reminds me of the miracle vitamins mail filling my mailbox.
    Very little factual data.

    Sort of like the smoke screen surrounding junk science...
    http://www.webexhibits.org/bogus/4.html

    PE informs us as to what is actually happening in the emulsion.
    From his information, I can make an informed decision.

    Reinhold

    www.classicBWphoto.com

  9. #209
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    Amen
    Items for sale or trade at www.Camera35.com

  10. #210
    Ian Grant's Avatar
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    Quote Originally Posted by Reinhold View Post
    So far this thread is over run with testimonials.
    Kind of reminds me of the miracle vitamins mail filling my mailbox.
    Very little factual data.

    Sort of like the smoke screen surrounding junk science...
    http://www.webexhibits.org/bogus/4.html

    PE informs us as to what is actually happening in the emulsion.
    From his information, I can make an informed decision.

    Reinhold

    www.classicBWphoto.com
    You pour the water in, you shake it al about, but then the dance steps stop you pour it all out and do the same with the fixer, start dancing again, then pour back do the same for longer with a few changes of water

    Then you get great negs, after finishing fixing & washing.

    Ian



 

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