silver based light sensitive emulsion 2-stage

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by jnanian, Feb 20, 2017.

  1. jnanian

    jnanian Advertiser Advertiser

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    is it possible to "salt" the gelatin and then coat the silver nitrate onto it,
    like one would do if making salt prints, albumen prints &c ?
    i was thinking to myself, rather than having a whole batch of emulsion in a container
    and using that, wouldn't it be great to just coat the silver nitrate as needed.
    maybe have a few different silver nitrate fluids, and a standard gelatin...
    or is there something that happens when everyting is mixed and heated that
    would disqualify any sort of simpler method?
    i know with calotypes+salt prints it is like this with albumen prints it is like this,
    with wet-collodion it is like this...

    thanks !
     
  2. Photo Engineer

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    Yes John, but without ripening or chemical sensitization if ends up being very very slow.

    PE
     
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    jnanian

    jnanian Advertiser Advertiser

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    thanks PE

    slow as in iso 1... or slower?
    i had a feeling the heating/ripening made it faster but i wasn't sure.

    it could be done just the same, like a salt print, but with salted gelatin and the silver nitate just coated on ?
    or would the pre-coated paper need to be heated up to soften it, so the silver+salts would play-nice ?

    john
     
  4. Photo Engineer

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    Probably about 0.1 - 0.5? IDK for sure but we can easily make 1 or 2 by precipitation and 25 with a little more effort.

    PE
     
  5. NedL

    NedL Subscriber

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    I might be out to lunch here, and this is untested, but I have an idea. I tried something similar to this recently with some difficult arrowroot paper and it worked pretty well. I'm not sure what you're planning to coat John... paper should work but I think the salted gelatin might be difficult to get to stick to glass.

    If you coat salted gelatin, let it dry, and then coat silver nitrate on paper, it will probably be like a salt print ( which often has a little gelatin in the salting solution ) and have a very limited shelf life. I usually figure no more than about 12 or 14 hours.

    With my difficult arrowroot paper, it had already been coated with salted arrowroot and dried, then I coated the 12% silver nitrate, let it sit for about 1/2 hour, and washed it well in several changes of DH2O.

    What I did then was let it dry for about 6 hours and then coat with 2% AgNO3, let it dry again for 3 hours, and print. I wondered at the time if the dried "silver chloride paper" might keep.

    I think the washing step will remove all the excess silver nitrate and any excess salt, so my hunch is that it might keep pretty well and have only silver chloride left. In your case the silver chloride ( or bromide, or whatever you are using ) would be in the gelatin. Since you're going to develop it, you wouldn't use that last 2% silver nitrate step that I needed for printing out, but just expose it.
     
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    jnanian

    jnanian Advertiser Advertiser

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    thanks ned and PE

    PE i am trying for very little effort, not a full on lab experiment in emulsion making.
    while i have done that sort of thing i'm looking to steamline my efforts so i can take pre-subbed ( gelatin+salted) paper
    and rod/brush a small amount of silver nitrate on it so i don't have to make more than i plan on
    using just then and there... kind of like what ned does when he makes salt prints &c/
    i don't mind making enough emulsion to coat 10 or 200 sheets of paper, but i'd rather not because
    it might go bad before i use it up, and then it will be $$ and time and effort wasted.
    as mentioned earlier, i know a variety of things to print on were created this way, from salt to albumen to
    the POP paper victor used to sell in ny ... it seems more cost effective to use as you need, rather than make a lot and hope
    you use it up ... i know collodion closes up (unless you use the honey/dry collodion recipe ) so i am guessing that gelatin
    and maybe arrowroot and maybe albumen still stay porous enough to let the salts and silver comingle and let the deveoping + fixing chemistry do its thing..

    thanks !

    john
     
  7. Photo Engineer

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    Thinking it over, it might be better to add the silver to the salts. This usually results in less problems in normal emulsion making and might work here. It also tends to give blacker images.

    PE
     
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    jnanian

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    excellent, so i'll make them as if they are salted paper/albuminized paper
    but with gelatin .. and just add on the silver later ..
    thans PE !
     
    Last edited: Feb 21, 2017
  9. nmp

    nmp Member

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    John, Hi:

    How will you make sure that you do not end up with excess Silver Nitrate so that you have a DOP on your hand as opposed to POP?

    (here we go again!)

    :Niranjan.
     
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    jnanian

    jnanian Advertiser Advertiser

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    :smile: for me that is half the fun of photography, not having a clue what might or might not happen !
    i figure with salt prints or albumen prints the silver washes out, with an unwashed emulsion on paper ( not glass ) the silver washes out
    so probably it will do the same thing with this and give similar results ... or maybe now :smile:
     
  11. w.out

    w.out Member

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    I've come in a bit late on this, but adding the salt to the jel first and then painting on the silver later is how I do salt prints all the time now. The paper has lasted for weeks unused this way, both the jel paper and the silvered paper.

    It's slow, but it's just salt print slow.
     
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    jnanian

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