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  1. #1

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    Why does selenium toner tones shadow area first? I am confused.

    It is commonly said that selenium toner affects the shadow first where as brown and sepia toners affect the highlight first.

    I can understand the latter. Highlight area has less silver so less time is required to finish the toning process to completion. But I have trouble understanding the first.

    Saying "shadow area" is the same thing as silver rich area. That would mean any attempt to tone it will take longer, I think. Then, why would selenium toner tones this silver rich area first while leaving highlight area largely untouched? If I did this, wouldn't selenium toner tone lightly silvered, highlight area to completion rather quickly?

    If I are to split tone, my (corrected) understanding is to selenium tone first, then sepia/brown. How does the selenium toner *knows* to leave the highlight part alone? Wouldn't that part tone to completion first?

    Please help this highly confused darkroom guy....
    Develop, stop, fix.... wait.... where's my film?

  2. #2
    Vaughn's Avatar
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    Shadows have more silver for the selenium to react with -- thus more of the differently colored selenium/silver compound gets formed and thus the color of the shadows is more pronounced. Less silver in the highlights -- less of the selenium-silver compounds formed thus weaker color change.

    With sepia toning it is more has to do with the percentage of silver being bleached -- highlights get total bleaching (not much there to bleach), the shadows often only get partial beaching, unless one bleaches all of the image away before going into the Part B.

    The last part -- selenium reacts with the silver components in the print -- but does not react much with the silver sulfated compounds created by sepia toning which are very stable. I believe one can do it either way -- I have heard mostly of sepia toning then selenium toning. I will be trying this this week -- with prints very lightly bleached then sepia toned -- then selenium toned. (Forte paper).

    Disclaimer -- I am not a chemist...this is just my limited understanding of the processes going on.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  3. #3

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    Thank you.

    I understand the shadow has more silver to react with selenium. Let's say my shadow has 10 silver and my highlight has 2 silver. Let's also say every minute, selenium toner can tone 1 unit of silver. If I toned this print for 4 minutes, shadow has toned for good amount (shadow tone first) but highlight has toned to completion 2 minutes ago leaving nothing for the second toner to react with.

    Even if I changed the numbers around a bit, it still end with the same conclusion that highlight will reach toward the maximum toning (completion) first. If this is the case, how would one split tone anything?
    Develop, stop, fix.... wait.... where's my film?

  4. #4
    MattKing's Avatar
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    Quote Originally Posted by tkamiya View Post
    Thank you.

    I understand the shadow has more silver to react with selenium. Let's say my shadow has 10 silver and my highlight has 2 silver. Let's also say every minute, selenium toner can tone 1 unit of silver. If I toned this print for 4 minutes, shadow has toned for good amount (shadow tone first) but highlight has toned to completion 2 minutes ago leaving nothing for the second toner to react with.

    Even if I changed the numbers around a bit, it still end with the same conclusion that highlight will reach toward the maximum toning (completion) first. If this is the case, how would one split tone anything?
    Just musing a bit here - I don't know the exact mechanism.

    Your scenario is based on an assumption - that the rate and amount of toning is linear and independent of how much silver is available for toning.

    If the toning rate is non-linear (logarythmic?), and based on the concentration of silver available for toning then the assumption is incorrect, and the amount of toning may very well be much greater in those areas that have a lot of silver available.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  5. #5

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    Yes, I made an assumption that the rate of change is linear - for sake of simplicity. But... does the rate of change itself really matter? Smaller amount of material vs. larger amount of material. In given time span, the reaction with the former will be completed or be closer to completion (percentage wise) than with the latter....

    The "amount" is not assumption though. Darker the image, more silver. Lighter the image, less silver.
    Develop, stop, fix.... wait.... where's my film?

  6. #6

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    By the way (totally unrelated to this thread), it was a happy day for me today. I spent a quality time in my darkroom! Yay, silver....
    Develop, stop, fix.... wait.... where's my film?

  7. #7
    Guillaume Zuili's Avatar
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    Quote Originally Posted by tkamiya View Post
    If I are to split tone, my (corrected) understanding is to selenium tone first, then sepia/brown. How does the selenium toner *knows* to leave the highlight part alone? Wouldn't that part tone to completion first?

    Please help this highly confused darkroom guy....

    The toner doesn't know anything. You know or you feel it and you remove the print.
    That's why there are good days and bad days in darkroom :-)

    Split tone is usually sepia first then selenium. Sepia tones only what you have bleached. So you deal with the highlights first.
    Rinse and then selenium.

    If you do selenium first you have 2 variables :
    - The highlights issue.
    - change of color of the selenium in the bleach. (usually reddish) it is beautiful anyway.


    G.

  8. #8
    Guillaume Zuili's Avatar
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    When I was assistant I asked why for the selenium.
    I got "it's like that"...
    Fine with me !
    :-)

  9. #9
    Vaughn's Avatar
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    The split toning I am familiar with is actually just selenium toning, not the combo of sepia and selenium toners. The shadows start to change color before the highlights...the old Portriga Rapid paper was one of the papers that worked well.

    I suppose the term dual-toning would fit better with what you are doing, but there might be some split toning going on as well.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  10. #10
    Thomas Bertilsson's Avatar
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    Selenium toner takes the silver in the print and converts it to silver selenide. Where there's lots of silver it is possible for the reaction to occur. Where there isn't any silver, it's difficult for the reaction to occur. Selenium is what's called a direct toner, meaning it does not require a bleach prior to toning.

    A sepia toner relies on silver to be bleached out of the picture, and re-halogenized into silver halide before a reaction with the sulfide toner can occur and turn the silver halide into silver sulfide. It isn't possible for the toner to react with silver directly, so the difference is that you turn it into silver halide before the chemical reaction can occur. Sepia is referred to as indirect toner, because it does require a bleach bath, and rehalogenizing bath prior to toning can happen.
    "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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