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  1. #21
    Photo Engineer's Avatar
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    How slow did you go??

    PE

  2. #22
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    Is it possible to get a film density range which will allow carbon transfer printing?

  3. #23
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    I believe that Chris is doing that right now.

    PE

  4. #24
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    I made some carbon-transfer prints from my last batch of emulsion, but it was tricky - the density range was too high!
    - Ian

  5. #25

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    I guess the question about how slow is really saying what's the ultimate quality? The best tonal range and the best grain = ? ASA? Ron maybe you can comment, but my guess is that the magic is in the formula, and therefore is not related to speed?

    I too have great admiration for those bromide images of the forties and fifties. They have sometimes that does not exist anywhere else.


    Russ


    Almost ready to start emulsion making!

  6. #26
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    Addition times from 1' to 15' are possible for this emulsion, but difficult o do by hand. The contrast will be quite low at 15' if everything behaves as normal, and the speed will probably move about 1 stop, but it may appear to slow down due to the loss in contrast. Here is a typical curve of the usual senitometric change with addition times from 8 - 14 minutes with a given emulsion. You can see what happens to speed and density as well as contrast.

    PE
    Attached Thumbnails Attached Thumbnails Curve vs addition time - old style.jpg  

  7. #27
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    Ron,

    A longer addition time would produce a lower contrast, I understand that, but why would it increase speed? Is it because the grains formed first would have more opportunity to grow larger at the expense of the smaller grains than in a more monodisperse emulsion?

    -- Jason
    All this has happened before, and all this will happen again.

  8. #28
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    You get more speed for the same reason that you get lower contrast. You get a broader size / frequency distribution. There are more fine grains and more coarse grains. With a very fast addition, you get grains that are more nearly alike and they are smaller.

    PE

  9. #29

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    Quote Originally Posted by zsas View Post
    Can I ask a silly question, I've never considered making my own emulsion to coat plates, film, paper, etc., but why does it seem that the workshops I have seen that create materials create types that are not often avail (eg a bromide only paper, which I believe is only made in matte by Slavich, AZO which only one company sells, or a slow ISO film 25 or so - which is not even made anymore, I think)? See my point? It's like these workshops teach how to make materials that are limited or impossible to get!

    Disclosure - I'm a fan of slooooowwwww film and bromide paper! Why's it seem the few places making this kind of great goods is at these kind of workshops?! I think you all are drawing me in

    Would love to make a tips to Rochester to see where it all began ( in the states at least)
    andy

    if you go to thelightfarm.com
    look under formulas
    there is a very simple sea water emulsion
    that the maker uses to coat plates
    and it only has a few ingredients ..
    no crazy chemicals, just silver nitrate
    seawater/ salt+water and gelatin ( from what i remember )
    salt prints were just saltwater and silver nitrate too, so this is just
    a little different ... if a 20year old college student with NO EXPERIENCE
    and a booklet from 1904 could do something like his at 2-3am ( in the 1980s )
    i think it would be a piece of cake for you

    have fun with your experiments!
    silver magnets, trickle tanks sold
    artwork often times sold for charity
    PM me for details

  10. #30
    zsas's Avatar
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    Quote Originally Posted by jnanian View Post
    andy

    if you go to thelightfarm.com
    look under formulas
    there is a very simple sea water emulsion
    that the maker uses to coat plates
    and it only has a few ingredients ..
    no crazy chemicals, just silver nitrate
    seawater/ salt+water and gelatin ( from what i remember )
    salt prints were just saltwater and silver nitrate too, so this is just
    a little different ... if a 20year old college student with NO EXPERIENCE
    and a booklet from 1904 could do something like his at 2-3am ( in the 1980s )
    i think it would be a piece of cake for you

    have fun with your experiments!
    Thanks J! Though my interest in photography is deep, but not at this point in the realm of coating due to other commitments, I'm just wondering why we've folks like me crying for the loss of APX 25 and Efke 25, but no one is making an artistian home brew for folks like me who'd buy a roll or two of 35mm/120 to play around with to 1) support home made goods, 2) a gap in our market? But maybe my query is self answered, Efke 25/APX 25 went under bc no one bought enough....
    Andy



 

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