16mm handmade emulsion

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by narigas2006, Feb 26, 2007.

  1. narigas2006

    narigas2006 Member

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    I have finally got a tough gelatin capable of traveling through my 16mm camera. Unfortunately, as a bad experimenter, I tried the pre-hardening before the gelatin was dried and it destroyed most of the emulsion. The other batch I have that is better coated i actually used a paint brush to do so. Anyway, here are some scanned samples (with a flatbed scanner):

    http://jcsmr.anu.edu.au/~rleao/DH_pics/Film_stripe1.jpg

    http://jcsmr.anu.edu.au/~rleao/DH_pics/Film_stripe2.jpg

    http://jcsmr.anu.edu.au/~rleao/DH_pics/Film_stripe3.jpg

    Now, with my other batch, I'll try to develop as reversal and then project it, then it comes another problem, while the emulsion survived the camera, I ain't sure if it would survive a 16mm projector, so, my question is, what could I use to toughen it to peel off? Could I spray lacquer or something like it after the development? What do you guys think? Many thanks.

    richardson
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    Wow. It's obviously really funky, but it would also look really cool projected, if you can get enough contrast to make it look good on screen.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    In the first sample, Kodak edge markings are clearly visible. This indicates that there is some of the original emulsion present in a form viable enough to image this edge mark. Could this be contributing to some of the image? To some of the problems? IDK, but it should not be there.

    You should add hardener just prior to coating the emulsion. You can add a humectant such as sorbitol. Many films are lacquered after processing to protect them. Kodachrome is one of those films.

    PE
     
  4. PHOTOTONE

    PHOTOTONE Member

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    Could it be that he is contact printing a 16mm negative? onto his homemade emulsion?
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    It says "survived a camera" so I assume it did. IDK, and that is why I ask. If emulsion remained behind from the previous film, it would certainly mess up the experiment in one way or another.

    PE
     
  6. htmlguru4242

    htmlguru4242 Member

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    Quite interesting. I agree with David that it looks a little funky, but PE has a good point about the previous emulsion being still on the base. Definitely keep this up though and let us know how it goes!.

    I wonder if you could find raw 16mm clear base to coat onto ...
     
  7. Jerevan

    Jerevan Subscriber

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  8. narigas2006

    narigas2006 Member

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    Hi PE,

    I should have explained, the kodak label is printed in the leader (I used clear polyester leader from kodak, not old film, so no remaining emulsion). The leader is black also because I inverted the scanned images in Gimp (they were actually negatives). I used sorbitol in the original formula. I'll try the lacquer before projecting it. Many thanks!
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    Best of luck to you.

    Any estimate of the speed?

    PE
     
  10. narigas2006

    narigas2006 Member

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    Thanks! I did some diffuse measurements (it was overcast) and using 16fps (1/30) and f4 i'd say ~15.

    And Jerevan, thanks for the tip! I just found out that they have precoated acetate clear leader!
     
  11. htmlguru4242

    htmlguru4242 Member

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    Wow, ISO 15, not too shabby. Any details on the emulsion?

    I wonder if reversal processing will boost the contrast like it tends to do for regular negative films?



    Keep up the good work!
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    I've been telling you guys that high speed isn't impossible. I have an ISO 400 - 800 emulsion in my head. I have not been able to make it, but when I do, it will teach me a lot on how to make it practicable in the home darkroom.

    PE
     
  13. Kino

    Kino Member

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    Cool job! Looks like nitrate going into decomposition!
     
  14. narigas2006

    narigas2006 Member

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    Thanks for all the replies! The emulsion was the amonia digest one that PE posted a while ago. The only difference is that I used acetic acid to neutralise the amonia (have to admit that it was not too accurate... I was dropping acid till the smell of amonia disappeared). The AgNO3+Amonia @35C was added to KBr @45C during ~15min continuously (I used a micropump, just because I have one... but dropping would also work). I don't have the silver gelatin book, but I remember looking at it and in there I think they just inject the AgNO3 + amonia continuously over 30s.

    Then all the basic steps, then, before coating:

    Alcohol - .4 ml/10ml of emulsion
    Sorbitol - ~0.3g/10ml
    Sensitiser. I use quanidine red .2% and use about .05 to .1 ml/10ml
    Photo Flo - .4ml/10ml

    then coat (after bathing the polyester leader with NaOH for 5min and washing)

    Then hardening (using PE formula from a few posts ago).

    Here was my grief. Due to hurry and anxiety, I did not wait for the gelatin to dry completely before hardening it... So, my nicely coated film had horrible sections where it came off. The second batch (that I wanna process in reversal) survived the hardening process easily but I wait 1 day to dry before hardening it.

    Anyway, many thanks!
     
  15. Photo Engineer

    Photo Engineer Subscriber

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    Ok, I think that is too much photo flo. I use 0.5 ml/100 ml of emulsion.

    But, most importantly, using that sulfur sensitization I described previously will probably boost your speed to over 25. I've gotten 40 in most cases. You will also get higher contrast.

    If you use the prehardener, it is a good idea to wash afterwards and then fully process the film. If the film is left in contact with the formalin overnight, it can fog the film. Formalin can do that. It depends.

    PE
     
  16. narigas2006

    narigas2006 Member

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    Hi PE, thanks for the info. I'll put less photoflo

    but the formalin did not seem to fog it too much. I coated another film with chrom allum and I'll see how it goes. By the way, I just came from the dark room and developed some film stripes in reversal and it came positive (very low contrast though - will try longer 1st developer). Once it dries I ppost the pics. Cheers