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  1. #31
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    [QUOTE=wildbillbugman;675714
    Ron, Is not mixing emulsions on a bench, like some of us are doing, "arcane"?
    I thought that keeping alive these "arcane" practices is the whole point of your Wokshops,The Light Farm. and this very Forum. If not, lets all just purchace digital camers, the latest Photoshop and "To Hell with It"!
    Just for the record: I for one have never said that I had any knowledge of Emulsion making, other than what I learned from you and a few others. All I said is that I was "practiced" and "Pracice" includes a bunch of failed attempts.
    Joy anf Cheerio to All,
    Bill[/QUOTE]

    Bill;

    I forgot to reply to this.

    I am trying to make emulsion making as fool proof and "un-arcane" as possible in my formulas. I hope you saw that in the emulsions we made. They are just about dump and stir.

    I'm trying to make the advanced emulsions easy as well, but they will cost more in terms of equipment though.

    I have not addressed finishing yet, I've merely used a standard condition more or less worked out by trial and error here at home with the bench top emulsions.

    I was not pointing a finger at anyone here in this thread, nor intending anything bad about anyones work. Sometimes though I feel like a person who has started a huge rock rolling downhill. I have to step back to get out of the way. Other times, people point at me and say "its all his fault and he doesn't know what he is doing" as the rock goes bounding down hill.

    So, that is all there was to my comment. I feel as if I want to be there to help!

    Now for finishing, you are using thiocyanate + gold. Here is the order of use timewise from early days to modern:

    Active gelatins > Allyl Thiourea > Thiourea > Thiocyanate > Sodium Thiosulfate

    Gold was used after about 1945 at Kodak with all of the above, but hypo was used exclusively for Sulfur sensitization since the 50s or 60s. Of course there is Reduction Sensitization (R type) which uses Stannous Chloride and a whole variety of other methods. Hypo seems to be the compound of choice for sulfur + gold though, but the hypo must be freshly mixed.

    Hypo and the others above put Silver Sulfide specks on the grain, but Stannous Chloride forms Silver metal specks on the grain.

    Other methods include addition of strong alkali, strong acid and a host of other methods to form a speck on the grain to "jump start" latent image formation.

    PE

  2. #32

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    Sensitizing Testing with Glass plate

    Quote Originally Posted by Ray Rogers View Post
    Hi Jim,

    You watched then do this?
    How long diid it take between coating and judgment?
    After this sort of test, what were their possible moves?

    Ray
    Hi Ray - I did watch them do this. Every 10 minutes or so, they would coat a glass plate with emulsion, expose it with a projection system. and develop (but not fix it). They would bring the plate into the emulsion chemist's office in a box and she would evaluate it quickly after removing the lid in full office light. She whould inspect it for fogging, and color change. Of course, since it wasn't fixed out, she had to work quickly. I'm not sure how long the process took to do, but the important thing was the record of samples 10 minutes apart which were done as the emulsion was sensitizing. Take a look at the attached file.

    Regards - Jim Browning
    Attached Thumbnails Attached Thumbnails sensitize test.jpg  

  3. #33

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    Hi Bill - I use glyoxal now as a substitute for formalin in my hardner. I use the same concentration, and it works well. This is the hardner I use on the matrix after it has been washed off. This makes for a much more durable matrix. Not sure how it would work in an emulsion though, that is a much more complex thing.

    Regards - Jim

  4. #34

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    Quote Originally Posted by dyetransfer View Post
    Hi Ray - I'm not sure how long the process took to do....

    Regards - Jim Browning
    Jim, what size plate are we looking at?

    I was wondering about
    how long and completely
    the emulsion was allowed to set.

    Interesting chart- do you have a close up of it, or know where its from?

    Ray

  5. #35
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    The method of using the glass plate that Jim describes above is limited in some cases such as our lab bench scale emulsions. A plate coating for a 4x5 takes about 6 ml of emulsion and over a 60 minute finish will therefore require about 36 ml of emulsion from a 200 ml batch as one example. That is a lot to use before you even start. To add to this, often we are making slow speed emulsions that cannot be easily printed by projection. Some print film and paper emulsions could not be tested this way due to speed and volume being made.

    Just some thoughts. It is useful but there is a better way.

    PE

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    A very long Three Dog Night

    Quote Originally Posted by Photo Engineer View Post
    "...people point at me and say "its all his fault... he doesn't know what he is doing"
    I must say that I have seen both sides of the story.
    I see a lot of misunderstanding mixed in with a lot of ego conflict / ego injury.

    Alas, we are but human!

    Thives of another animal's breast milk!

    Ray Rogers

  7. #37

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    Hi Ray - the plate size was 4 x 5". Not sure how long it took the gel to set or if the plate was chilled, but I imagine that it was. Obviously, you want to develop the image as soon as possible after coating it so the emulsion doesn't continue to evolve. The chart was a glass plate (I think) that was placed in a very old looking projector - black wrinkle finish. But the projector looked to be very well made and the projected image was sharp. I don't know what they developed the plate in, but I doubt it was pyro.

    Regards - Jim

  8. #38

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    Quote Originally Posted by dyetransfer View Post
    Hi Ray - the plate size was 4 x 5". Regards - Jim
    OK,

    Thanks Jim.

  9. #39

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    Quote Originally Posted by Photo Engineer View Post
    The method of using the glass plate that Jim describes above is limited in some cases such as our lab bench scale emulsions. A plate coating for a 4x5 takes about 6 ml of emulsion and over a 60 minute finish will therefore require about 36 ml of emulsion from a 200 ml batch as one example.
    Ron - You may have missed it, but Bill said he was going to make 1L of emulsion, so he should have plenty to test with. But for much smaller batched, this method would cut in quite a bit to the final volume.

  10. #40

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    Quote Originally Posted by Photo Engineer View Post
    The method of using the glass plate ...
    Just some thoughts. It is useful but there is a better way.
    OK - did I miss the description of the better way? Or have I just forgotten it?

    Kirk

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