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  1. #1

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    An emulsion suitable for bromoil

    I'm in the process of making an emulsion suitable for bromoil.

    I did some attempt in the past with an unwashed emulsion recipe.

    I'm trying now with a washed silver-bromide emulsion as described by Mark Osterman in the second edition of Christopher James book. The trick of doing bromoils is to create a matrix with a special bleach for a regular bw print. Since the bleach also hardens the emulsion while bleaching it, the emulsion itself shouldn't contain hardeners. At least this is my understanding.

    In the past I used commercially available emulsions and only those without hardeners worked for making bromoils.

    I made an emulsion without adding chrome alum in it. I still have to try it for bromoils. It prints fine in Neutol WA, but it is a little bit too weak (melts at room temperature). With two coatings of emulsion this problem becomes less apparent, but is there a way to make the gelatin more consistent without using chemical hardeners such as chrome alum?

    Thank you
    Interested in converting a Polaroid 110B into a compact 4x5" rangefinder camera? Check out how I did it here.

  2. #2
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    Hi Fulvio,

    I would love for you to try my latest negative emulsion with your bromoils. It is a washed, unhardened bromide formula. I use it to coat dry plates and it seems very durable. I wish I could link you to the recipe on The Light Farm, but I've had a terrible case of 'It's Summer!' for the last month and haven't gotten it posted yet. If you'd like to give it a try, pm me for my email address and I'll send it to you. If you're not in a hurry, it will available online within the month.

    Best of luck,
    Denise

  3. #3

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    it's autumn you have a pm
    Interested in converting a Polaroid 110B into a compact 4x5" rangefinder camera? Check out how I did it here.

  4. #4

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    It's finally summer, here in Oregon. September is always a beautiful month.

  5. #5
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    The Osterman emulsion coats just fine onto paper as long as the process temperature is kept at or below 68 deg F. It gives good contrast in my experience.

    It might be the developer or fix, or even the paper support you are using.

    PE

  6. #6

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    Yes temperature might have been a problem... I used this formula while it was quite warm in here (25-30°C, that is above 68°F)... Now that it dropped to 20-25°C things are getting better. I actually played a little bit with the emulsion suggested by Osterman.... Perhaps my first batches were too thin. I had to triple coat to get successful results. With the new batch and lower ambient temperature with two coats it's just fine and acceptable, but haven't tried it with bromoil yet. It's quite slow (I haven't rated it, but I assure you it's very very slow)... I wonder for how long it will keep in the fridge. I added a little thymol as preservative. No chrome alum for the reasons I mentioned. When I need it, I scrap the necessary quantity and melt just that. So far I always prepared small batches (100-250 cc) because I'm afraid that making larger ones (500-1000) won't last enough before I use it all for prints. How long do you think it would keep?
    Last edited by Fulvio; 09-16-2008 at 07:48 AM. Click to view previous post history.
    Interested in converting a Polaroid 110B into a compact 4x5" rangefinder camera? Check out how I did it here.

  7. #7
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    It should keep for about 1 month in a refrigerator at about 3 - 5 deg C.

    PE

  8. #8

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    that's great... But is there a way to extend considerably the shelf life of an emulsion? or do you know any formula for a home-made emulsion that lasts a very long time?
    Interested in converting a Polaroid 110B into a compact 4x5" rangefinder camera? Check out how I did it here.

  9. #9
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    Gelatin is a common culture medium for growing bacteria and mold samples. Silver metal is itself an antisceptic. These two balance out to allow an emulsion to keep for at least 1 month, but I've been lucky sometimes and have gotten 6 months out of an emulsion. The natural trend is to decomposition of the gelatin by 'bugs'.

    Using rubber gloves and not breathing into your emulsion are good starts. We observed that if an emulsion was handled carelessly, it went bad faster. Dirty hands, breathing, sneezing etc. were definite problems.

    Otherwise, nature takes its course. Sorry.

    PE

  10. #10

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    I undestand. However I've observed that commercial made emulsions keep longer than 6 months. I've been using a FOMA for months (almost 12) and its still good...
    Interested in converting a Polaroid 110B into a compact 4x5" rangefinder camera? Check out how I did it here.

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