Availability of different Liquid Emulsions.

Discussion in 'Alternative Processes' started by waynecrider, Aug 1, 2005.

  1. waynecrider

    waynecrider Member

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    I need to know if there are other liquid emulsions available than Liquid Light and what if any are the differences between them all. I have not used any at this point. I need to make a cost analysis and consider any differences in abilities between different emulsions before I proceed. Thanks for the help.
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Maco/Cachet offered a few Liquid Emulsions, graded and VC. They may be available under other brands--I'm not sure who the original manufacturer was. Check J&C.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    It is possible to make your own liquid emulsions in the darkroom in about 45 minutes total time with only 7 chemicals. The results will be between slow enlarger and contact speed and will have contrast grades of about 2 or lower. This includes hardening agents and spreading agents.

    Formulas for the emulsion are posted on the net or available from participants in this or other forums.

    With additional work and at least one more chemical, you can achieve up to ISO 25 and ortho sensitivity. These formulas are not posted or currently available, but I understand that they may be in the not so distant future.

    Your biggest problems with the commercial and home grown emulsions alike will be adhesion to the substrate, spreading (coating uniformly) and hardening. Commercial emulsions often remain unsold on the shelf for a long time. They are not high volume items. Therefore, they may deteriorate with time. IDK, I have avoided using them.

    PE
     
  4. waynecrider

    waynecrider Member

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    That's a good point. I wonder how affected they are in the long term.

    AK making your own, I'm interested. Where to look? Google it?
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    Dr. Bruce Kahn (google) of RIT has posted his emulsion formula on the internet. It is a contact speed silver chloride emulsion that takes 3 ingredients and makes a very nice grade 2 image. You have to be careful with the formula, or it may give clumping and fog specks, but it is quite nice and compares favorably in tone with Multigrade IV paper at grade 2.

    Do not use Knox food grade gelatin for its preparation. Make sure you get a good grade 'hard' gelatin such as sold by the Formulary. It should have a Bloom Index above about 175.

    With keeping, the commercial grade emulsions could degrade and fog, and the gelatin might be attacked by bacteria or mold. IDK. I avoid them. They may be sterilzed and may keep well physically but chemically I have my doubts. In the worst case they would behave like keeping a box of paper or film on the shelf at room temperature a over long period.

    PE
     
  6. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Check the "Chemistry Recipes" section here, and I think you'll find one emulsion formula.
     
  7. doughowk

    doughowk Subscriber

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  8. gandolfi

    gandolfi Member

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    this is one GREAT book - BUY IT!!
    there are many! recipies of making your own emulsion...

    BUT

    I have tried a few:
    Liquid Light : beautiful surface!! but too difficult for me... fogs to easily..
    TETENAL WORK : also great blacks. I have no clue whether you can get it in America, but here in Denamrk it is EXPENSIVE!!
    FOMA: cheap!! (in appearence. it needs at least two layers of coating, so the price goes up..)
    MACO: the same as FOMA. needs a lot of emulsion, so it gets a little annoying to work with.
    just tried the VC. result was dissapointingly flat images, even using filter 5..
    (this Could be me - needs to experiment more.)

    the VERY BEST - price/workability is SE1 by Kentmere..
    totall matt in surface (you might add some glycerine to make a slightly more glossy surface..)
    BUT it works like a charm. one coating - easy to coat. Works like "normal" fiber based prints.
    works VERY well with different toners.

    and it keeps well over time.
    I allways buy 5 liters at a time. It is a lot, but as I have students, it is the amount to buy.
    also when buying this in 5 liters, the price goes way down..

    only one warning: IF you buy (do it with some friends and split the costs) be aware, that the bottle it is sent in, is NOT light proof. OPEN ONLY in a dark room...

    so

    SILVER GELATINE and SE1 and you are getting some where..
    and you can get it in the same place..(plus brushes)

    www.silverprint.co.uk

    have FUN
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    The formula posted on this forum is an old Kodak formula, published for patent purposes. It was available in a pamphlet upon request.

    It works just fine, but is needlessly complex compared to that of Dr. Kahn. You could go either way. Both work just fine, but the Kodak emulsion here is a bit faster IIRC and takes a lot longer to make.

    PE
     
  10. jnanian

    jnanian Advertiser Advertiser

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    the photographer's formulary sells formu-lite ( sorry about the bad spelling) ... never used it, and from what i remember it might be rebranded maco ...
     
  11. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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  12. glbeas

    glbeas Member

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    So how do you calculate the moles into actual weights and measures?
     
  13. Ole

    Ole Moderator Staff Member Moderator

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    That is basic chemistry, this is more advancd labwork. :D
     
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  15. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    There are also some formulas for salted paper emulsions and others in Greene's _Primitive Photography_.
     
  16. waynecrider

    waynecrider Member

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  17. glbeas

    glbeas Member

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    That's fer sure! Think you can figure out how an amateur like me could use that formula with any sucess? Like a translation into a cookbook recipe?
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    Here it is in English then:

    To 90 grams of distilled water, add 5 grams of photo grade gelatin and bring it to 40 deg C. Stir constantly. When dissolved and there are no floaters of gelatin, add 3.51 grams of reagent grade Sodium Chloride (NaCl). (I find dissolving the gelatin first is best)

    Note, stirring should be continuous, and strong, but should not whip air into the gelatin salt mixture. Don't overdo the stirring, but don't underdo it either. Overdoing it will give you bubbles, and underdoing it will lead to a bad emulsion with foggy large grains.

    In another container, dissolve 5.1 grams of Silver Nitrate (AgNO3) in 10 ml of distilled water.

    Bring the gelatin and salt solution to 60 deg C with stirring. Turn out the room lights and turn on a red or yellow safelight, and then add the 10 ml of silver nitrate to the salt solution as you continue stirring.

    Set a timer for 5 minutes and hold the mixture at 60 deg C for 5 minutes then place in a light tight container and place in the refrigerator. This will keep for about 1 month with no deterioration, perhaps longer.

    You can coat this on about any surface with a paint brush if you remelt it at 40 deg C. I suggest a good camels hair brush with loose bristles removed.

    If you have trouble with even coating, add a drop or two of photoflo 200 to the melted emulsion. If you need hardening, add a few drops of 10% chrome alum to the melted emulsion. If you add any hardener, the emulsion must be used as soon as possible or it will set up to a putty like mass.

    Exposure time will typically be in the contact paper range. I've used about 3 seconds to normal room light. You should get a good black image with a contrast of about 2.

    How is that?

    PE
     
  19. glbeas

    glbeas Member

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    Photo Engineer, you da man! Thanks!
     
  20. Dwane

    Dwane Member

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    0.06 moles NaCl = 3.51 grams (with one mole = 58.5 grams)
    0.03 moles AgNO3 = 5.10 grams (with one mole = 170 grams)
     
  21. Ryuji

    Ryuji Member

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    Ron, I don't know which formula you are referring to but speed of ISO 25 is not hard to beat without spectral sensitization. There are many key points but iodide distribution should be tightly controlled so that dislocation can be introduced at the very end of grain growth stage. Plus, precipitation condition should be controlled to reduce coefficient of variation (especially to the larger diameter side--smaller grains will simply be junk grains that simply and harmlessly waste silver) so that the digestion condition for S+Au can be optimized. Also, incorporation of dopants that act as shallow electron traps is important.

    Regarding the coating problem. The ease of coating depends on the viscosity of the emulsion, which is determined by factors like gelatin concentration, gelatin avg molecular weight, coating temp, hardener, etc. I have found that a hardener that works slowly (taking a few days) is best for hand coating because they don't increase viscosity during the coating stage. Spread can be improved with a suitable surfactant, but most of the good ones are very bubbly and foaming becomes the problem with hand coating with brush. Many defoamers impaired spreading and adhesion in my experience. So I did some systematic search for suitable surfactant that maximizes the coating efficiency and produce very low foaming. Surprisingly, emulsion patents don't even mention the agents I use... though the agents themselves are not uncommon.

     
  22. Ryuji

    Ryuji Member

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    Ron, your emulsion has some problems. The emulsion is not even sulfur sensitized, so the speed and contrast are too low to be useful for most applications. Another problem is that the supersaturation is too high with your 3M AgNO3 jet, unless you can somehow jet it through very narrow nozzle with high pressure (this technique is disclosed in recent Fuji patent, issued in 2005). Also, pure chloride emulsion is not very useful. Most modern chloride emulsions contain 1-10% bromide and/or 0.1-1% iodide. Kodak patents often use AgCl core, AgClI shell and cover them with AgCl. Fuji patents often introduce AgBr shell inside AgClI layer. I've followed those inventions (but with different dopants) and they work beautifully.

    The emulsion is best stabilized with PMT (and TAI, especially if sulfur sensitized). Optimal amount of PMT can also increase speed. If the emulsion is to be kept for some time, the emulsion should incorporate a suitable biocide as well.

     
  23. Baryta

    Baryta Member

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    A few comments...

    Ryuji, I belive this was Dr. Kahn formula, not Ron's.

    Did you actually make this one yourself and thus speak from experience with this formula?

    I see many real and potential problems with this formula myself, but I didn't jump up and tell Dr. Kahn this when we met just after Dr. James died at the close of the last century.
    (Any idea why I didn't?)

    There are good pure chloride emulsions too Ryuji.

    The most modern photographic material contains no Silver halides at all.
    So what?

    I doubt TAI is the optimal stabilizer for this emulsion.

    Baryta
     
  24. Ryuji

    Ryuji Member

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    I actually discussed problems with that student lab formula with Dr Kahn and he told me that the formula was something he inherited when he took over that course, and continued to use it because it's good enough for the student lab. He is not interested in teaching how to make practically useful emulsions in such setting anyway.

    I also don't agree with your comments on more technical matters.

     
  25. Photo Engineer

    Photo Engineer Subscriber

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    Ryuji; I had lunch with Bruce a few weeks ago and I am fully aware of the source of the emulsion and the problems associated with it. We discussed this emulsion thoroughly. Bruce is an expert on chloride emulsions and finishing. Since we are both former EK engineers, we could have a free ranging discussion without the restrictions we have here.

    I showed him my pictures and the comparisons to Ilford Multigrade IV at contrast grade 2 to illustrate the tone scale that I am getting. Of course, he is not endorsing anything I have done, but he is fully aware of it.

    I have worked hard to fix the problems as I saw them (and as you and I discussed before), but even as-is the formula is a grade 2 Azo speed (contact speed), black toned formula. It is quite nice except for the pepper grain which we discussed before as well. I have fixed that.

    For an azo speed grade 2 paper, it performs very well. I have since gotten ~grade 1 and grade 3 and grade 4 from it as well, as stated in another thread. I can do this through modifications in the making method.

    Just FYI, I do indeed use a small injector orifice at high pressure. That is well known and has been for years. How else do you think a large quantity of concentrated AgNO3 can be delivered in a small amount of time? That seems to be obvious to me.

    In fact, when I was doing real work, I remember blowing a seal because I let the pressure go too high on a make. Now that was a mess.

    It seems that I must agree with Baryta regarding his comments on the technical details of this emulsion. PMT slows it down, and keeping is good without TAI for my purposes, so I have never even tried adding it. I have also achieved slow enlarger speed from it using some modifications you said in another message were not useful, but which I knew would work. I have spectrally sensitzed it as well.

    For preservative (biocide), if needed, I suggest using Thymol, 10%, about 0.1 ml / 100 ml of emulsion. So far it keeps well for me for a few months.

    So, I have made this formula over 10 times, each one of the first 7 being improvements, and now I am at a stable formula which I have repeated about 3 times and which is the basis for further experiments. It is the basis for an AgCl, and AgClBr, and an AgClI. They are all simple and intended for the home hobbyist.

    If they bother you, just remember that they work.

    PE
     
  26. Ryuji

    Ryuji Member

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    Ron, I'm not bothered by your work. Your approach to emulsion making is 1920-like and I could immediately point out a LOT of things to improve, some of which I already posted.

    The method of mixing silver and halide using high velocity linear flows in a closed container without rotational agitation is new on patent literature. It only appears in US Patent in 2005. As discussed in that patent, the mixing is highly efficient as a premixer to use before the kettle during growth stage to keep supersaturation low. The one you are talking about is known from 1960s. There is nothing new there, and it helps little in terms of avoiding area of very high supersaturation in the kettle.

    Any emulsion maker knowledgeable in chloride emulsion would know that the optimal amount PMT can INCREASE speed of <100> bounded AgCl and AgClBr emulsions (S sensitized). Tani figured out the mechanism in 70s and he published this results in many papers and also in his book, so it's very well known. TAI is most effectively used in addition to stabilize S sensitized emulsions. You might never felt the need of using TAI because you don't give optimal S or S+Au digestion.

    Even in <111> bounded grains, a certain small amount of PMT can be added without lowering speed.

    For record, I usually make far more than 10 batches to test formulae and find optimal parameters. Most emulsions are subdivided into several portions and they are digested in different conditions to find most useful conditions.