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  1. #141

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    Hi, I will chime in just for the Halibut,
    I coat emulsions on glass and only glass. I coat not only silver emulsions but also Pt/Pd/Au photo reactive coatings and dichromate /pigment coatings . I never use a subbing. I find that surface preparation is absolutely critical. I have my, rather elaborate, glass cleaning procedure published in www.thelightfarm.com And in www.alternativeprocesses.com. I never get frilling. My process of cleaning glass might be too much trouble for some people. Basically , if a layer of water stands on a vertical sheet of glass without breaking, you should be alright.
    Good luck
    Bill

  2. #142
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    ... It forms a gooey whitish mass ...
    Yes, that is the mess I get. Introducing Acetone into the mixture gives this mess every time but extra heat doesn't get it to dissolve. Adding methanol does give this mess too but to a lesser extent and additional acid will cause the mess to redissolve. Unfortunately, far too much acid is added and you'd nearly choke on acetic acid fumes. (Excess acid will negatively affect emulsion speed.)

    My last tries yesterday eliminated the acetone. It seems any amount of acetone destroys the this Grafix acetate beyond usefulness.

    However, adding melted gelatin to warm methanol seems to work. I can make subbing number 2, (the one Glafkides gives for nitrate) with no problem. Plain gelatin on acetate subbed with this mixture will adhere nicely. After drying I can't seem to peel it off by picking at a cut edge with a fingernail or by tearing the film. Will have to try the "scotch tape test" next time.

    One concern I do have is that the methanol distorts the acetate as it evaporates. Not nearly as much as acetone does but a flat piece will not be flat but wrinkled after drying. The methanol causes the acetone to swell (which is the point) and maybe less methanol and more water should be used?

    What might the difference be between using methanol and ethanol?


    I wonder what the wet-media films are subbed with? Somewhere it was written that it is a latex coating. The Grafix PET films, as well as 3M and Dupont films, work the best as far as off the shelf items are concerned. I am guessing, though, that the Grafix product is really made by 3M or Dupont. (3M and Dupont only sell B2B in large quantity.)

    Minwax polyurethane is a new one. Maybe it has potential.

    ( On a side note, since someone asked me about this, Glafkides books, "Photographic Chemistry" from the 1950s are generally expensive. If you author search under the man who translated these books from French you can sometimes find copies at a much better asking price. His last name was "Hornsby." Be careful, though, because Mr. Hornsby wrote his own book entitled "Basic Photographic Chemistry" at about the same time frame. )
    All this has happened before, and all this will happen again.

  3. #143

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    Agfa Patent 1976

    I was sure that I had a simple subbing formula copied from a book I read, but damned if I can find it.

    I also find some of the formulas complex:

    Agfa patent UK 1976 11216 or EP0003627 A1
    solution A

    demin H2O 2460ml
    disodiumhydrogen phospate 6.3g
    xitric acid 20.4g
    urea 432g
    ammonium sulphate 72g


    Solution B
    aqueous colloidal solution of silica 888ml
    demin H2O 939ml
    6N sulfuric acid to bring ph to 3 21.1ml


    Soution C
    20% aqueous solution of formaldehyde 576ml


    add B to A at 40 degrees C, stirring at 6000 rpm for 2 hours. Add C. stir 15min. decrease rpm to 3000 for 2 hours at 40 degrees C


    change ph to 6 with 110ml 2N sodium hydroxide and 300g gelatine stir 300rpm for 1 hour!

    Other interesting Patents
    US3535147 A


    (1) Applying a first coating comprising a dilute aqueous solution of a polyvalent metal salt selected from the group consisting of ferric, stannic, stannous, chromic, and zirconium salts plus a polymer film swelling agent to the polymer film support;


    (2) Drying and curing this first coating to form a first subbing layer;


    (3) Applying a second coating comprising an aqueous gelatin solution containing a polyvalent metal salt selected from the group consisting of ferric, stannous, stannic, chromic, and zirconium salts plus a polymer film swelling agent to the first subbing layer; and


    (4) Drying and curing this second coating to form a second subbing layer.


    This one confirms the use of latex:

    US3320191 A
    A sample of photographic baryta coated paper stock was coated on both sides with a 15 g./m. coating of 50:50 solids blend of polystyrene latex and styrenezbutadiene (60:40) latex. This coated paper was very hydrophobic to water and showed a moisture pickup (Cobb test) of approximately 0.02 g./ 100 cm. after 8 minutes exposure to water at 70 F. A 1.0 g./rn. sub coating of the following composition was then coated over the face side resinous layer.
    Material: Weight, gms. Water 907.9 Chelating agent 2.5 Wet-ting agent 1.5 Sodium meta-borate 2.0 Casein 7.6 Polystyrene latex (32.5% solids) 70.0 Gelatin 7.6 40% formaldehyde 0.9
    The sub coating was dried by passing the paper first through an air drier at 160-180 F. for l-l5 sec. and then in front of a bank of infrared heaters at 240280 F. for -20 sec. The paper was then coated on the face side with a suitable photographic gelatin-based emulsion, and dried. When processed, no evidence of emulsion frill was noted. The same paper without the sub layer showed a complete sloughing off of the emulsion during processing.
    When the same latex coated base was subbed with a 1.0 g./m. sub coating composed of equal parts (by solids weight) of a resin latex mixture of polystyrene resin latexstyrene butadiene resin latex combination (45 :55 by solids weight) and gelatin, adhesion was not considered passable--an objectionable amount of emulsion coating could be rubbed away.

    1949 US2461474 A

    A film base of cellulose acetate was coated with the following gelatinous substrating composition:
    Parts Gelatin 0.73 Water 1.33 Acetic acid 1.20 Diphenylsulfone 1.34 Methanol 75.53
    An anti-static gelatin composition suitable for the subbing of a photographic film support, which comprises a gelatin subbing composition containing from 0.5 to 1.5% of gelatin, from 1.33 to 15% of water, from 78 to 95.4% of a solvent for said support, and from 0.5 to of a diphenylsulfone of the following general formula: which comprises a gelatin subbing composition containing from 0.5 to 1.5% of gelatin, from 1.33 to of water, from 78 to 95.4% of a solvent for said support, and from 0.5 to 10% of diphenylsulfone.

    1939 US2196775 A


    A cellulose acetate photographic film base made from cellulose acetate containing about 40.5% acetyl was coated with a solution having the following composition:


    Grams Polymerized methyl acrylate 1 Acetone 10 Methyl alcohol After this coating had dried the following solution was applied:


    Grams Cellulose nitrate 1 Methyl alcohol 40 Butyl alcohol This layer was dried and a gelatin sub was then applied having the following composition:


    Gelatin g 1 Acetic acid g 1 Water cc 25 Ethyl alcohol cc 25 The gelatin layer was dried and a photographic gelatino silver halide emulsion was then applied in the usual manner.

    1938 Mr Babcock US2110496 has the coating speeds and formulas! Enjoy!
    :

    Click image for larger version. 

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    Russ
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  4. #144
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    There are several things to learn here.

    1. Subbing was applied to the film as it ran over a large metal roller which kept it stiff and flat until the solvents evaporated. Thus, the film was flat. Doing it by hand loses this advantage. The support can develop wrinkles or kinks.

    2. Latexes are often used as subbing layers.

    3. Many supports are just bombarded electrostatically, and then plain gelatin is laid down on this charged support. It adheres wonderfully. Sometimes a latex layer is laid down instead of gelatin.

    4. Metals in the subbing layer can be used, but many cause severe defects such as total fog. Tin and Iron are among them.

    5. Using formalin is ok but remember it is a gas in water and is also a carcinogen.

    I just buy pre-subbed film support and avoid this hassle. Or, I use plates.

    PE

  5. #145

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    More on subbibg

    Thinking of your weather - keep warm!

    Found this today:

    This step consists in applying to a cellulose nitrate or cellulose acetate support the following solution:

    Potassium hydroxide___; ______________ __, 1
    Ethyl alcohol _________________________ __- 1000
    This solution is applied at a temperature of about
    50° 0., although the temperature range may be
    between 30 and 80° C. This solution will be ap
    plied to one face of the support. on which it is
    desired to put a non-halation coating, by means
    of machines which are well known.

    Russ

  6. #146
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    Russ, that is for an anti-halation layer, applied to the back of the film. It might be an undercoat under the emulsion layers, but that is not clear. In any case, the film would have to be washed after application if the emulsion is being coated on it. The residual Sodium Hydroxide would be bad stuff. I advise caution. This forms Sodium Ethoxide which will react with the support and make it more polar. And, more alkaline probably.

    PE

  7. #147
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    Russ,

    If you refer back earlier in this same thread, you will find that I did some work on hydrolyzing PET with NaOH (sodium hydroxide). It works and coats beautifully. There are two problems, though. One, it is difficult to process a large sheet because the material must soak for about two hours for the necessary hydrolysis to occur. So if you want to process something larger that you can do in a print tray, for example, you need a machine or some kind of spool setup, think like a large developing tank, which means lots of caustic 3.0M NaOH around. Two, the PET surface MUST be thoroughly washed or it will spoil the emulsion, processed or unprocessed, after a few weeks.

    Flame treating PET is a much more convenient process but unfortunately gives inconsistent results. Beautiful when it works and useless when it doesn't.

    Gotta tell you, subbing is vexing. If you start you will want to find a solution to the problem and it can make you nuts. The trouble is you are trying to get a water based concoction to tick to a hydrophobic surface. Essentially the same problem as putting latex water-based paint over oil-based paint. The paint peels off and so does emulsion.

    And, when you read old recipes like Mr. Glafkides, you will find that our materials are not exactly the same as they were 50 to 75 years ago. Today's gelatin is different. Subtle denaturants have been added to liquids so people can't make drugs out of them and so forth that ruin the basic idea. If I had a nickel for every time I thought I had this one licked ....

    Someday, we will lick this one. We need to because I am concerned that the pre-subbed material can be hard to get and IDK what the market for it is.

    Yeah, PE, don't say it.

    -- Jason

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    All this has happened before, and all this will happen again.

  8. #148

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    Acrylic Glass might work

    Hi,

    acrylic glas has been mentioned a few times in this thread but there is not a lot of information whether it could be used for dry plates. Even if I've only just began to experiment with dry plates on acrylic glass I'm already quite sure, that one can make it work. Here is an example of of Rollei liquid emulsion on a 9x12 cm dry plate developed in Rodinal 1:50 and printed with grade 0. The plate is not prepared in any way and the emulsion not hardened, so I'm sure frilling can be reduced to a very practical level. I shot some nice outdoor images today. I will keep you posted how things develop.

    best,
    Sebastian

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  9. #149
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    Is acrylic glass the stuff that can be made into a thin film? I don't think subbed polyester is going to go away in the foreseeable future, but redundancy in any system is a very good thing! We're never completely out of luck, because I don't think regular glass is going anywhere, but I'd hate to lose the option of making film without resorting to subbing acetate (stinky process!! -- although it works fine.) Sebastian, Thanks for sharing your work. Cute monkey!
    www.thelightfarm.com
    Dedicated to Handmade Silver Gelatin Paper, Film, and Dry Plates.

  10. #150

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    I don't think that you can obtain it as thin film. I'm using 1,5mm thick plates right now, which are the thinnest the company I got them from (already cut to the right size) could provide. They fit in a regular sheet film holder nicely if you stick them in with a bit of tape. That's ideal for my testing. If I can make them work, I'd prefer them to normal glass for several reasons. Next step is hardening the emulsion and maybe NAOH treatment before coating if hardening doesn't prove to be sufficient (but my feeling is that it might not be necessary).

    The monkey sits on my workbench in the darkroom and is a good test object. However today I printed the images of my first outdoor test which give a better idea how the stuff behaves. These are not try yet, I'll scan them tomorrow. I'm not happy with the Rollei emulsion. Even on an overcast day, contrast is extremely high. I shot them around Iso 0,25/0,5, developed the plates in Rodinal 1:100 for a few minutes only and printed with grade 0 to 1,5. That produces an usable image but nothing special. But it is OK for the first tests.

    Best,
    Sebastian

    PS: I think I've learned most of the information on your website by heart. This will prove to be a huge help when I start to produce my own emulsion. Same applies to all the information PE provided here. Thanks to both of you.



 

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