Melenex subbed film base

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by dwross, Nov 21, 2008.

  1. dwross

    dwross Subscriber

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    Hi All,

    For all you fearless and open-minded photographers, willing to brew your own emulsion, but unwilling to load your mule with glass plates, the Photographers' Formulary has Melenex subbed film base back on the market.

    This morning I posted a bit of information on using the product. I love the stuff. I use the same recipe as I use for glass plates. I imagine a commercial Liquid Light type product would work also.

    http://www.thelightfarm.com/Map/FilmNegatives/MapTopic.htm

    Denise
     
  2. CRhymer

    CRhymer Subscriber

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    Hello Denise,

    That is good news. I bought 60 linear feet of it about a year ago, but have not done much yet. I am currently working on wet-plate.

    Cheers,
    Clarence
     
  3. Kirk Keyes

    Kirk Keyes Member

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    Clarence - how's that going? Made any 20x24 plates yet?
     
  4. CRhymer

    CRhymer Subscriber

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    Hello Kirk,

    In a word, no. It was a horrendous task to get the wet-plate chemicals shipped - hazmat, etc. etc. It is starting to get cold here, but nothing compared with what it will be like in six weeks. I have been fixing a Cirkut camera, which is rather time consuming, but a new emulsion and some collodion plates are on the list for December. The Cirkut camera will not be happy in the cold (and neither will I). It is a real pain to fiddle with equipment when it is minus 45 C., so I will be doing more indoor work. There is not a lot of light here in the winter, save for the occasional meteor.

    Cheers,
    Clarence
     
  5. dyetransfer

    dyetransfer Member

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    The Melinex film is the roll I had here for coating my matrix film. It is the last roll in existance with the proper subbing layer which won't take up dyes and stain the hilights in a dye print. Dupont no longer stocks this film, but you can order a factory run for about $ 100K.

    I also sold Bud the trough coater (the one in the plexi box) and the complete travelling slot coating system, including emulsion making equipment, sink, massive ultra flat aluminum vacuum platen, and the coater itself. Also the HEPA filtered dryer. This would be just the thing for coating large glass plates up to 32 x 42". After coating the sheet and setting the gel, you lift it off the coater and dry it in the HEPA filtered dryer. After drying, you can cut it up into any sized plate. This coater would be uniquely suited for this purpose. AFAIK, Bud at the Formulary hasn't used this piece of equipment, and would probably be willing to sell it to anyone interested in coating large glass plates. It would be perfect for plate work, and it occupies a very minimal amount of space considering that it is a sort of mini-factory. Please see my DT materials manual at www.dyetransfer.org to see pictures of all this.

    Regards - Jim Browning
     
  6. wildbillbugman

    wildbillbugman Member

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    Denise,
    What is wrong with glass plates? I love glass. Even if there is no image at all on it. A transparent,fluid solid! What could be more magical? You don,t need a mule. Just a wheel or two,or three or four. Plastic is tacky by comparison.
    Cheers,
    Bill
     
  7. Shangheye

    Shangheye Member

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    I have to say that for someone like me, just about to enter the own emulsion arena, this is a god send. It removes one variable (the subbing/holder issues) and allows me to develop my competence, and is yet another avenue for experimentation. I for one have already bought some :D Kal
     
  8. Hologram

    Hologram Member

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    Just wanted to remind you again that you might bath TAC (triacetate) film in a highly alkaline solution to make its surface hydrophilic.

    As for PET films there are some “write-on film“ for overhead projection, mine are from FOLEX. They're “crystal“ clear. They obviously accept certain types of gelatin. For example, Aldrich's 300 bloom swine gelatin proofed to stick well on this type of film. The layers well survived Neutol development and EDTA bleaching.
     
  9. dwross

    dwross Subscriber

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    Bill,
    I think glass is magic, too. I just recently found out that scientists still aren't exactly sure what the physics of glass are. Too cool. And beautiful, and clear, and cheap, and almost certainly available for the rest of my emulsion-making days. But, I also agree with Kal. Melenex removes some of the initial hurdles of working with dry plates. It gives people time to collect holders and big cameras. Unfortunately, Jim's supply, now at the Formulary, is limited. I just hope it hooks a whole bunch of people on making emulsions before it runs out :smile: Beautiful glass will be there when it does. There might even be a new source of subbed film.

    Holgram,
    Thank you for the thoughts on pre-treating film. I have trying out your ideas on my ToDo list, but I'd love to see you get to it first and tell us all about it. Are you currently making emulsions or planning on it? You would certainly make some great contributions to the field.

    Denise
     
  10. Hologram

    Hologram Member

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    I actually did make some AgX emulsions I coated on PET film – very few on TAC also (It turned out to be difficult to get small quantities of TAC). One problem in the area I am interested in, holography, is that the usual PET (as well as a great many plastic) films are optically active, birefringent. They change linear to random polarization. This leads to severe “cosmetic“ defects on the holograms. Hence, PET film definitely is not my first choice. My assumption though was that for photographic applications this will not be of an issue.
     
  11. dwross

    dwross Subscriber

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    I'm sorry I've somehow missed the posts about your emulsions. I love reading about other people's efforts and I try to keep my eyes open for the opportunity. Are you going to try on the Melenex, or does it interfere with holograms, too? What's TAC?

    Your comment reminded me of a 'just-for-fun' I recently saw.
    http://blogoscoped.com/files/stripes.html
     
  12. Hologram

    Hologram Member

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    I understand Melinex, Cronar, Mylar etc. are all about the same stuff, polyethyleneterephtalate, PET.
    Due to the ”cosmetic” issue I cannot use them for regular work.

    TAC is cellulose triacetate, the most common (photographic) film base material.
     
  13. dwross

    dwross Subscriber

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    Thanks for posting the definitions, including PET. I had meant to ask about that, too, but I was time-sharing my brain with cooking for Thanksgiving. Fortunately, I don't think I added silver nitrate to the pumpkin pie!

    I'm 'old school' science writer. Even with Google and Wikipedia at our fingertips ready to answer questions, I like to see a Three Letter Acronym (TLA) spelled out at the beginning of a new communication. APUG can be a great place for education if we avoid in-group talk.

    About your emulsions: Can you make any meaningful progress on your explorations with the materials readily available to you? This is a question I'm trying to hammer out for myself. How much can we learn - now - so that we are ready to leap forward when a crucial material or piece of the data puzzle comes our way?

    Denise
     
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  15. Hologram

    Hologram Member

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    I wholeheartedly agree.



    I guess it's safe to say that progress can be made with the materials I've access to – as long as these materials remain available. Here in Europe, buying photo chemicals becomes more and more difficult.

    It turned out to be rather tricky to get consistent emulsion batches. This may be particularly true for the small quantities I am dealing with (100ml of emulsion only).
    Coating layers of uniform thickness may be another challenge sometimes – given I've to concentrate my emulsions through a freezing/thawing cycle in order to increase gelatin/AgX concentration. This occasionally causes somewhat unpredictable results.

    My emulsions are very simple. They involve no dopants etc. The only “sophisticated” part consists in adding a small quantity of KJ. And then, prior to use, I apply a 1% ascorbate pH6 (reduction) sensitization bath.
     
  16. PHOTOTONE

    PHOTOTONE Member

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    Perhaps I am just uninformed here, but I wonder...who makes the subbed base stock for the worlds film makers such as Ilford, Kodak, Foma, Filmotec, Gevaert, etc? Couldn't there possibly be found another vendor for small quantity, since it is still made in large quantity for commercial film production? I wonder if a small quantity of subbed base could be purchased from a company such as Ilford?
     
  17. Kirk Keyes

    Kirk Keyes Member

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    Before anyone asks, "KJ" is potassium iodide in German.
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    Ahhh yes, I remember a heated argument with an APUG member who insisted that a particular formula had no iodide. The formula clearly had KJ addition in it. :D Oh well.

    As for making support, Kodak and Fuji (last I heard) made their own support on huge casting wheels. Another manufacturer was Dupont and another was ICI in London. So, there are few manufacturers and there are many many types of support and subbing that can be placed on them.

    The particular Melenex supplied by the Formulary uses a subbing that is tailored to work with dyes and emulsions. Many other subbed Melenex supports absorb stains and dyes and are therefore useless with some photographic processes.

    PE
     
  19. rmazzullo

    rmazzullo Member

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    I found some of the patents for Melenex a while ago, and it appears that the subbing compound is added during the manufacture of the polyester film base itself, and not afterwards.

    When I looked at other patents regarding subbing polyester after the manufacture, there was one in particular that mentioned that their subbing compound passed the dry and wet adhesion tests very well. However, the test emulsion they used contained congo red dye, and had stained the subbing compound.

    My question is...if we are coating a basic B&W emulsion, would we have to be concerned with staining? If sensitizing dyes are added to the emulsion, would they stain enough to cause difficulites, if at all? If we do not have to be as concerned with staining, as with dye transfer, can we use a similar method of subbing polyester?

    Bob M.
     
    Last edited by a moderator: Dec 1, 2008
  20. Photo Engineer

    Photo Engineer Subscriber

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    If a subbed film can be stained by dyes, then there is a chance that sensitizing dyes can get into the support and stain it. So, the answer is that it depends....

    PE
     
  21. AgX

    AgX Member

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    There are at least two manufacturers of photo-grade film base in Europe:

    -) Agfa : PET

    -) Opco (an Agfa spin-off) : TAC

    Though both sell masterrolls only…


    Agfa of course get their PET base from themselves (they don’t coat on TAC).

    IlfordPhoto and Filmotec get their TAC from Opco.

    Ferrania might be casting TAC for their own use.
     
    Last edited by a moderator: Dec 1, 2008
  22. AgX

    AgX Member

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    PET base for the industry not neccessarily needs to be subbed. It can be activated (radicals-forming) by plasma-technology within the coater just prior to coating.
     
  23. Photo Engineer

    Photo Engineer Subscriber

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    And you just happen to have a bombarder in your darkroom? :D

    This high voltage electron bombardment equipment is neither inexpensive nor easily and safely used in a home darkroom. You will probably also disrupt all radio and TV reception along with cell phones within about 100 - 500 feet of your site. :D

    PE
     
  24. AgX

    AgX Member

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    PE,

    You totally got me wrong. Of course I know of the inherent problems of such a kind of preparation and I never thought of any DIY use of it.

    But I just wanted to indicate that not neccessarily all photo-grade PET stock on offer is subbed.
     
  25. Steve Smith

    Steve Smith Subscriber

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    We (at work) use polyester sheet including Melinex to screen print conductive silver ink onto. A lot of polyester is available with ink receptive surface treatments. Some of these would probably also be receptive to emulsion.



    Steve.
     
  26. Photo Engineer

    Photo Engineer Subscriber

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    Sorry. I said that more tongue in cheek. No offense intended.

    PE