Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,813   Posts: 1,581,587   Online: 882
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 21
  1. #1

    Join Date
    Aug 2010
    Location
    Norway
    Shooter
    Multi Format
    Posts
    189
    Images
    22

    Mixing Foma liquid emulsion

    I've tried searching the forum and google for an answer, but haven't found it. So I try to ask here.

    How much water should I add to Foma Liquid emulsion?
    Do I need to heat the original container first or do I just use a plastic spoon or something to take out only the emulsion I need?
    How much do I need to coat a 8x10" paper with two layers?

    How to apply the emulsion I have found good information about, but not about how to mix.

    Guess I at least have to spend the first kilogram of emulsion just for practice, but it would be okay to start with the right mix and work from there. I have ordered the book Gandolfi recommended, but it won't arrive until a few weeks.

  2. #2
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,521
    Images
    65
    If you can, remove just the amount you need and melt it at about 100 - 110 F (or 35 - 40 C).

    You should add a surfactant and hardening agent for best results. However, you should run a test first to see if these are needed. As for diluting, some emulsions need it and some do not. The company should supply specifications, but if they do not, you may need to use some trial and error to find out what to use.

    Usually, the spread or "lay down" of a silver halide emulsion of this sort is about 5 - 15 ml per square ft. That would be about 45 - 135 ml per square meter at a rough estimate. Again, experimentation is necessary if the company does not give any data.

    PE

  3. #3
    Mustafa Umut Sarac's Avatar
    Join Date
    Oct 2006
    Location
    İstanbul - Türkiye
    Shooter
    35mm RF
    Posts
    3,965
    Images
    108
    Hello Grainy ,

    I found below. May be PE can have a look at , it was at the FOMA site.

    PHOTOGRAPHIC EMULSION
    In general
    There are technically given limits for the use of photopapers. To extend these limits and so to support the creative power both amateur photographers and
    professionals, this universal emulsion was developed. By its correctuse, the results limited only by users´ own imagination, can be achieved. The photographic
    emulsion enables creating works of great value both in artistic and photographic respect. Of some importance is the fact that standard results can be achieved
    provided the correct emulsion handling procedure is applied.
    The photographic emulsion is made by using the most modern production technology. The emulsion features medium contrast and extremely high covering
    power which enable gaining a wide scale of halftones even by a relative high yield of 3 to 6 sq. m per 1 kg of emulsion. For the majority of common applications
    (particularly on smooth surfaces), only one layer of emulsion is sufficient to be spread. An advantage of this high-speed emulsion are short exposures which
    make large size enlarging possible. With the majority of developers, this emulsion gives a neutral to mildly warm image tone.
    The emulsion can be spread on the most different bases, as e. g. wood, textile, glass, china, ceramics, metals, leather,stone, concrete, plaster etc. What is,
    however, important is the photochemical inactivity of the base. This condition not being met, the base should be treated with a suitable waterproof layer (e.g.
    epoxide varnish, etc.). Another important requirement isa good wetting power of the base surface. To ensure good coherence of the emulsion to the base, the
    non-wettable surfaces should be treated with a suitable preparation layer before spreading the emulsion.
    Example of a preparation solution composition:
    Gelatine (1% solution) 100,0 ml
    Chrome alum (10% solution) 0,5 ml
    Ethanol 96 % 4,0 ml
    With this solution, only thoroughly clean and dry objects should be treated.
    Packaging
    The photographic emulsion is supplied in light-tight PE-bottles. The commercial packaging consists of a cardboard box containing:
    Photographic Emulsion 1 kg (Open in darkroom only!)
    HARD Hardener 15 ml
    Yield
    1 kg of emulsion is sufficient to prepare an area of 3 to 6 sq. m according to base type, surface quality and thickness of the layer spread.
    Processing
    Due to a high silver content and a relatively thick layer when spreading the emulsion manually, energetic developers are recommended, e.g. Fomatol LQN and
    Fomatol P from the FOMA product line. To effectively stop the development, Fomacitro citric acid-based stop bath is suitable. For fixing, Fomafix fixer is
    recommended. Corresponding processing chemicals of other manufacturers can be used as well.
    Warning: It is important that a perfect fixing and an adequately long washing be cared about (at best in running water), otherwise the resulting photographic
    image would not be long-term stable.
    FOMA HARD Hardener
    This special hardener is supplied together with the emulsion. The hardener ensures good mechanical resistance of the layer spread; its use is therefore
    recommended for all aplications. It should be added directly to the emulsion melted, the recommended volume being 15 ml per 1 kg of emulsion. According to
    individual requirements concerning the hardening grade of the emulsion layer, this volume can be varied to some extent. Instead of the hardener supplied, other
    suitable hardeners can also be used, e.g. formaldehyde (1 to 5 ml of 10 % solution per 1 kg of emulsion), or in combination with the same volume of chrome
    alum solution (10%).
    Emulsion handling procedure
    In a well-darkened room furnished with a suitable safelight illumination (identical with the illumination recommendedfor fixed-contrast FOMA photopapers), the
    emulsion is melted at about 35 to 40 oC in a water bath. Under continuous stirring, necessary additives are added to the emulsion close before its use:
    particularly the hardener (to ensure the mechanical resistance of the emulsion layer during processing), sometimes also Fotonal wetting agent (to make the
    emulsion spreading more uniform).

    The way of emulsion spreading should be adjusted to the shape of the respective object and tested in advance. After heating up to 30 oC, horizontal areas can
    be furnished with a single emulsion layer by spreading the volume proportioned before. Having set to a jelly, the layer can easily be dried in vertical position.
    Flat, not very coarse surfaces can be covered by a brush. In both last-named cases, 2 to 3 layers should be spread, the next one every time after the preceeding
    layer has been thoroughly dried. Regarding nonuniformities caused by the manual emulsion spreading, a yield of only about 3 sq. m per 1 kg of the emulsion
    should be taken into consideration in both these cases.
    Note: For each application only a necessary emulsion amount should be taken away from the stock and melted. The non-spent emulsion should not be re-chilled
    (contains hardener!).
    Storage
    The photographic emulsion should be stored in darkness, preferably in closed original packagings (other chemically inactive packagings can also be used, e.g.
    PE- and PP-bottles, glass and the like). An important storage condition is a stable temperature ranging from 4 to 10 oC. The emulsion, however, should not be
    allowed to freeze. Although disinfectants have been addedto the emulsion during production, the emulsion should be handled with care to avoid contamination
    with bacteria and moulds. The above conditions having been kept, a shelf life of the stock emulsion (without hardener) of about 6 months can be taken into
    account.
    Recommended way of packaging waste disposal: After a thorough rinse out, PE-, PP-bottles and cardboard boxes are recommended to discard in special

  4. #4
    gandolfi's Avatar
    Join Date
    Jan 2005
    Location
    Denmark
    Shooter
    Large Format Pan
    Posts
    1,804
    Images
    370
    Quote Originally Posted by Photo Engineer View Post
    If you can, remove just the amount you need and melt it at about 100 - 110 F (or 35 - 40 C).

    You should add a surfactant and hardening agent for best results. However, you should run a test first to see if these are needed. As for diluting, some emulsions need it and some do not. The company should supply specifications, but if they do not, you may need to use some trial and error to find out what to use.

    Usually, the spread or "lay down" of a silver halide emulsion of this sort is about 5 - 15 ml per square ft. That would be about 45 - 135 ml per square meter at a rough estimate. Again, experimentation is necessary if the company does not give any data.

    PE
    10+ years of experience tells me this:

    Don't dilute!!
    There will be a small bottle with hardener in the package - I never use it!

    Just apply an even layer - let it dry and do it again. IF the results are grey/spotted, you have used too little emulsion - if the image looks highly contrasty and slightly yellow - then you have used too much.

  5. #5

    Join Date
    Aug 2010
    Location
    Norway
    Shooter
    Multi Format
    Posts
    189
    Images
    22
    Thanks. The last text says "melt the emulsion in a water bath", but not spesific about dilution. Guess I just start with a little water to see how liquid the emulsion changes when heated to 40 degrees.

    My plan is to cut a 8x10" in four pieces and coat them. Then I have one or two papers for testtrip, one for normal exposure and one with dodge/burn. If that works well I can coat several 8x10" and start printing. Bought some really heavy weight, textured cotton paper, so it will be interesting.

  6. #6
    gandolfi's Avatar
    Join Date
    Jan 2005
    Location
    Denmark
    Shooter
    Large Format Pan
    Posts
    1,804
    Images
    370
    Quote Originally Posted by Grainy View Post
    Thanks. The last text says "melt the emulsion in a water bath", but not spesific about dilution. Guess I just start with a little water to see how liquid the emulsion changes when heated to 40 degrees.

    My plan is to cut a 8x10" in four pieces and coat them. Then I have one or two papers for testtrip, one for normal exposure and one with dodge/burn. If that works well I can coat several 8x10" and start printing. Bought some really heavy weight, textured cotton paper, so it will be interesting.
    as said: NO dilution.

    and PE says you have to melt in 35-40degrees hot water. In my experience it is too low. I always melt at about 45-50degrees.(not higher!)(runnng water!). If you can the emulsion to melt at 35-40 degrees, you'll have trouble keeping it liquid..

    (take a tray and fill som ehot water in it. In there you put a piece of cloth. A plastic container (used boxes for "Ferrero Rocher" works great!!) is put ober the cloth (the cloth makes it stable). Take the container with the melted emulsion in a can with hot water and place that in the tray too.. this way you have hot inviroment around the emulsion all the time while you coat..)

  7. #7

    Join Date
    Aug 2010
    Location
    Norway
    Shooter
    Multi Format
    Posts
    189
    Images
    22
    Ah, I diluted the first "batch" with water. But I didn't make more than a maybe 50ml and 4 10x15cm sheets. I will throw them away and try again tomorrow.

    Thanks a lot for the input.

  8. #8

    Join Date
    Aug 2010
    Location
    Norway
    Shooter
    Multi Format
    Posts
    189
    Images
    22
    First problem I discovered with the paper was that it curled upwards in the middle after i started applying the emulsion. And I need to buy a new thermometer, it stops at 40 degrees.

  9. #9
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,521
    Images
    65
    If this emulsion is thick at 40 deg C, then it indicates a very high percentage of gelatin. Normally, gelatin is coated between 5% and 10%. Any higher leads to difficulty melting as noted above. I'm afraid I cannot give much advice in this case as I try to stay at what I am comfortable with in terms of concentrations.

    If the paper curls, you may be putting down too much emulsion at one time, you may have humid darkroom conditions or you may be using a cold press or soft textured or low weight paper. I use 100# paper, or higher, and I do not use cold pressed.

    I wish you the best of luck.

    PE

  10. #10

    Join Date
    Aug 2010
    Location
    Norway
    Shooter
    Multi Format
    Posts
    189
    Images
    22
    I used some high quality 425g/m2 watercolour paper with quite heavy texture. Guess it's cold pressed, but I do not fully understand what the text "Not (cold pressed) grain fin" means.

    It was easier to coat it when I cut 15x20cm sheets instead of 10x15cm, but they still curled in the middle. They're drying now, so I will print tomorrow or monday.

    After I have gotten used to coating and printing on paper I plan to coat different types of rock and wood with emulsion. What can I coat the emulsion with to make the picture more or less weather resistant? I looked at my local art shop and they sold this http://www.hahnemuehle.com/prod/en/2...ive-spray.html and this http://ghiant.com/i/varnish2o.jpg

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin