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  1. #21

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    Quote Originally Posted by Michael R 1974 View Post
    It can help to think of Selenium as an intensifyer. The degree of toning is proportional to the amount of silver present, whether toned partially or to completion. This is why it works as a proportional intensifyer for negatives (ie contrast increase). Metallic silver converted or coated with Selenium blocks light more efficiently than untoned metallic silver. Hence the contrast increase in selenium toned negatives, and the enhanced d-max in papers.

    Regarding the differences in toning properties of papers in Selenium (degree, color), there are several factors. In addition to all the emulsion characteristics, my understanding is the degree to which the emulsion is hardened in manufacturing also contributes considerably.

    Michael,

    Thank you. Does this mean that if I have an area where there is a lot of silver and another with very little, say 10 and 1, and tone it for X amount of time, if the former becomes 15, the latter becomes 1.5? - so that my assumption that less silver area will tone to completion first? Then what I need to research is the rate of change rather than the amount of change.....
    Develop, stop, fix.... wait.... where's my film?

  2. #22
    Thomas Bertilsson's Avatar
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    Quote Originally Posted by tkamiya View Post
    Just so we are clear - I am not playing devil's advocate. I am trying to understand the WHY portion of these processes so I can use them to my advantage. I happen to have couple of prints right now that I think would be a good candidate for split toning. So far, the results are disappointing. It is one thing to take conventional wisdom and use it - but it is another to understand the reason behind those wisdom and really take an advantage of it.
    OK. Devil's advocate is a good technique for preventing groupthink, and that is a good thing. I didn't mean anything negative by that, quite the contrary. It's a commonly used technique in meeting discussions that someone is specifically assigned to play that role to break conventional thought patterns.

    Anyway, I suggest that for you to get good results with split toning, you don't need to understand the chemistry portion of it. Is it impossible to suggest to just accept that selenium tones 'bottom up' and sulfide toners tone 'top down'?

    You have two ways of using the two toners in combination:
    1. You bleach and use sulfide toner first, and after the following wash you use selenium. The selenium strongly affects the results of the sulfide toner.
    2. You use selenium toner first to protect the shadows, then bleach and use sulfide toner. This usually gives a much more subtle effect.

    You can also play around with bleach/sulfide, and then another round of bleach/sulfide. That yields interesting results as well.

    It matters what paper you use. Check out http://www.moersch-photochemie.de/co...nowhow/lang:en
    It has lots of examples of what you can do with various toners, bleaching, etc.

    Good luck! I hope you find a good way of working with these toners.

    - Thomas
    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

    "...the heart and mind are the true lens of the camera". - Yousuf Karsh

  3. #23

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    I'm afraid I can't do that Dave.... (ref. 2001 Space Odyssey)

    One of my weakness is, I must find out why certain things work in a way it does and this is no exception. I'll report back when I find the reason why Selenium acts this way.
    Develop, stop, fix.... wait.... where's my film?

  4. #24
    artonpaper's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    It can help to think of Selenium as an intensifyer. The degree of toning is proportional to the amount of silver present, whether toned partially or to completion. This is why it works as a proportional intensifyer for negatives (ie contrast increase). Metallic silver converted or coated with Selenium blocks light more efficiently than untoned metallic silver. Hence the contrast increase in selenium toned negatives, and the enhanced d-max in papers.

    Regarding the differences in toning properties of papers in Selenium (degree, color), there are several factors. In addition to all the emulsion characteristics, my understanding is the degree to which the emulsion is hardened in manufacturing also contributes considerably.
    The idea about intensification makes sense. Portriga, a graded paper, used to acquire very red shadows long before the highlights or middle tones. I've used poly toner, another direct toner, highly diluted, on Portriga, but it would tone the highlights first, leaving neutral darks if you caught it in time.

    I had a friend years back that would split tone Portriga in selenium, and then tone in an iron blue toner, which toned the lighter tones blue. So thinking about this suggests that there was still untoned silver in the areas that toned blue.

    And interestingly, I've had students take a print out of the bleach intended for sepia toning and stick it in the selenium. That resulted in instant redevelopment, with selenium tones.

  5. #25

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    I contacted Mr. Tim Rudman and he replied. He has generously given me his permission to share his response. Here are his key points:

    Quote Originally Posted by Quoted from e-mail from Mr. Tim Rodman - shared with his permission
    It isn't as simple as the amount of silver present, because as you point out, there is a much greater abundance of silver in the dark tones of a print. More important are the size of the silver grains and their type. They are not all the same and the larger more abundant grains in shadow areas convert to silver selenide first.

    There are some exceptions as some types of coarse silver grains, mostly in the darkest tones, resist selenium conversion totally.

    Bear in mind too that most paper emulsions are a mix of silver bromide and silver chloride in varying ratios, and some have silver iodide too. They yield metallic silver after development of course, but grain size (in the paper) is not uniform - far from it, and grain size is a major factor in toning outcomes, as it is with bleach & redevelopment, where you recreate your own silver halide mix. But it is more than just grain size - hence my brief ref to 'chinese prints' in the book.
    I took a liberty to combine two emails from him and removed some portion of it for clarity.

    I went ahead and ordered his book on the subject. I'll be studying it once it arrives.
    Develop, stop, fix.... wait.... where's my film?

  6. #26
    Thomas Bertilsson's Avatar
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    Quote Originally Posted by tkamiya View Post
    I contacted Mr. Tim Rudman and he replied. He has generously given me his permission to share his response. Here are his key points:



    I took a liberty to combine two emails from him and removed some portion of it for clarity.

    I went ahead and ordered his book on the subject. I'll be studying it once it arrives.
    Thanks to you for sharing, and to Dr Rudman for educating us. That is good solid information.
    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

    "...the heart and mind are the true lens of the camera". - Yousuf Karsh

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