Liquid Emulsion - Spraying it on a big surface

Discussion in 'Alternative Processes' started by matita, Mar 20, 2013.

  1. matita

    matita Member

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    Hi there,
    I'm planning to use liquid emulsion on a 9ft colorama in order to get a approximately a 9x12 ft photosensitive area.
    For what I mean to do spraying seems the best way to apply a coat of emulsion.
    I do have some questions though.

    - I'm planning to dilute the emulsion with some clear methylated spray, around I read that the suggested ratio would be 600ml of spirit for a litre of emulsion, any chance that I can dilute more?

    - How much diluted emulsion you think I should have to cover such a big area?

    - I'd like to use one of those high pressure sprayers used in gardening, they create a nice mist and I believe that would be optimal to spread an even coat, but I'm afraid that the emulsion could get in contact with some metal part, any suggestion for a sprayer that could fit the job?

    Looking forward to get your input!:D
     
  2. Ian Grant

    Ian Grant Subscriber

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    You need much more specialist equipment. This is an area where I have considerable experience (over a decade) as we sprayed emulsion commercially .

    First you need a good spray gun & compressor, a garden spray is inadequate, then you need good fume extraction and an airline respirator so thet the air you breathe is from outside the darkroom, then you need a means to develop, fix, wash etc which will require a lot of water and drainage. The compressor needs to be isolated from the darkroom so it feeds clean air to the airline respirator which is fed by the same airline as the spray gun.

    We used an emulsion which had been designed for spraying, we made our own, and regularly worked around the size you're looking at as well as larger.

    Ian
     
  3. Zishe Breitbart

    Zishe Breitbart Member

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    Hi Matita

    Some time ago I worked with liquid emulsion (Rollei Black Magic) as well; I tried different procedures on surfaces around 1.5 sqm.
    Foam paint rollers, brush paint rollers, sprays, brushes. I achieved the best results using large, very soft brushes. Sprays tended to form bubbles.

    I used as well diluted emulsions up to 20% spirit / 80% emulsion, maybe at greater dilutions the bubble-problem can be avoided.

    I cannot remember how much liquid I applied exactly, I guess 50-100ml /sqm. Of course it depends on the desity you want achieve. If you apply a very thin layer the picture will be slighlty transparent.
     
  4. matita

    matita Member

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    Thank you for your answer!

    I read carefully what you said and I understand your point, to be honest I don't have that kind of equipment, but it is also true that I'm not looking for the most polished finish.
    I do have a well ventilated big space, and I was planning to use some gas mask as extra precaution.
    My idea was also to do developing, stopping and fixing spraying. I'm really stubborn and I'm going to test this procedure in any case, but I will be happy to know if you think it is possible to achieve something and if not why?
     
  5. matita

    matita Member

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    Thank you very much Zishe, I might consider a brush as well:smile:
    In your opinion do you think that a 1:1 dilution would be pushing it a little too much?
     
  6. Zishe Breitbart

    Zishe Breitbart Member

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    Not sure how a 1:1 dilution will look.. I warmly recommend doing some experiments on small plates first. Results can be quite surprising when working with emulsions.
    What will you use as substrate?

    Zishe
     
  7. matita

    matita Member

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    I will use thick paper (colorama), I don't expect it to be a though material to apply the emulsion on, but we'll see..
    Certainly I will do quite a bit of testing on much smaller sizes (liquid emulsion is expensive...) before trying anything big :smile:
     
  8. bdial

    bdial Subscriber

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    Your respirator needs to have cartriges compatible with the solvent you are spraying.
    While the respirator can protect you from the solvent fumes, you also need to have sufficient oxygen content in what you are breathing. Your darkroom's ventilation may not be up to the task.
    That's probably the reason for Ian's recommendation that your breathing air come from outside the darkroom, though he might be able to elaborate.
     
  9. boswald

    boswald Member

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    Do you remember textured ceilings? That stuff was pretty thick, so the nozzles may be close to what you need. This is gelatin, and if you heat/thin it enough to get through a small nozzle, it may take many coats to build up enough. A deep fuzzy roller may be a better, if lower tech method.
    Let us know how it goes, David
     
  10. matita

    matita Member

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    The space should be adequate, I'm using a huge photographic studio (F1 cars got photographed there). I will make sure to get the right cartridge though, thanks!
     
  11. matita

    matita Member

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    This is a great idea, the only thing that worries me is that these guns look like they all got a metal nozzle. Did someone ever got liquid emulsion in contact with metal? Did it get terribly ruined?