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  1. #1

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    SPECTRAL SENSITIZER

    Hello

  2. #2

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    Sorry. I don't know how that happened.
    Hello PE,
    I am addressing you personaly because it was you who first suggested the Sand's Dyes to me. I had an idea this morning. I am thinking about spliting a batch of emulsion with relatively low Iodine content. To part A, I would add the stanard, for me, amount of I And the stanard dose of SDA3057. tThis would make my standard red sensitizing portion. To part B, instead of using SDE3008, I would cut by 1/3 the leval of dye and Iodine. This, from past experience, will not form J agrigates, but remaine a red,green sensitizing dye. I have found that SDE3008, given enough I, Is a Green and red sensitizer. I wonder, if I use SDA3057 as the only dye, in 2 separate concentration, would the grains retain their specific sensitivities after being mixed enough to coat.
    Cheers,
    Bill

  3. #3

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    PE,
    Another idea that I have been considering for a while is: 3 layers of a red, a green, and a blue sensitized emulsion. Any advantage over simply mixing all 3 ?
    Cheers,
    Bill

  4. #4
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    if an emulsion is under dyed, then any excess dye can migrate during keeping and change things. A 3 layer system will pretty much prevent that. However, you do not need a blue sensitive layer. All emulsions are blue sensitive. You only need 2 layers.

    PE

  5. #5

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    Thanks PE,
    The only question I have knawing at me is: Way back when you first recommended the Sands dyes, you recommended spliting the batch into Three parts : Red senstized with SDA3057, Green sensitized with SDE3008 and a blue sensitive emulsion with no dye. Why the third portion? Portions one and two are blue sensitive.
    Curious,
    Bill

  6. #6
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    There were several reasons:

    1. All sensitizing dyes reduce inherent blue speed, and this was my way of maximizing blue speed.

    2. It further isolated the two spectral sensitizing dyes.

    3. I goofed! < yes, I just could have gone with 2 emulsions instead of 3.

    PE

  7. #7

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    Thanks, Ron!,
    You can see the type of things that bother my brain. Thats may be why I keep insects as pets!
    Happy Labor Day. So let us all labor!
    Bill

  8. #8
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    Bill;

    We found some very nice photos of you and your mantis recently. Brought back old memories.

    Well, the memories are not that old, I am!

    PE

  9. #9
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    Reviewing some information on dyes and wanted to put this info out there. Maybe it is useful and maybe not. These items are available from Alfa Aesar (www.alfa.com)

    Kryptocyanine is 1,1'-Diethyl-4,4'-carbocyanine iodide. Alfa has 1,1'-Diethyl-4,4'-carbocyanine bromide, see http://www.alfa.com/en/gp100w.pgm?dsstk=H32481 Is this the same thing, except the bromide salt and would function as an IR dye?

    Also have 1,1'-Diethyl-2,2'-carbocyanine iodide (or bromide) see , is this useful as a substitute for 1,1'-Diethyl-2,2'-carbocyanine iodide, aka Pinacyanole(chloride)? See http://www.alfa.com/en/gp100w.pgm?dsstk=H31540


    They also have Ethyl Red and Eosin Y.
    All this has happened before, and all this will happen again.

  10. #10
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    Good find Jason! Reasonable prices too.

    The Eosin Yellow is as cheap as can be. I assume this is the historic green sensitizer people have been using, as opposed to Eosin-Methylene Blue (?... haven't cross referenced the big list yet...)
    If you are the big tree, we are the small axe

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