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  1. #1
    kb3lms's Avatar
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    Thinking about 35mm Home Brew

    Sometime over the next year I have decided to try and make my own emulsion and coat onto film. Right now, I am just beginning to collect parts, pieces and materials to do this. Naturally, wanting to make this as difficult as possible, I'm going to start with 35mm. 120 or sheet film would surely be easier but I don't have a camera for it. (That might change but it's not happening right now)

    Clear 35mm film leader is readily available. Assuming I can figure out a way to "sub" the material, does this leader work well as a base? My plan at the moment is to use the subbing recipe from the Wall textbook but am definitely open to other suggestions if anyone can point me at a good formula.

    Thanks!

  2. #2

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    Since it's easier to do sheet film why don't you just buy a view camera? It wouldn't be too expensive and making your own size would make your cost significantly higher.

  3. #3
    hrst's Avatar
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    I didn't have very good results with the subbing layer mentioned. I had problems with base wringling when the subbing dries.

    I had great results in "subbing" POLYESTER with corona discharge. I used a commercial corona unit and also made one by myself as shown here: http://www.youtube.com/watch?v=StgbV766dqQ . However, it broke down for an unknown reason and when I was repairing it, I got a jolt (just 230 V ;D) and left it alone for a while. I'm thinking of designing an easier-to-build, smaller and safer alternative... When it happens, I will give instructions to build one.

    The result with corona treated polyester, coated with coating blade, was nearly perfect. I shot it in medium format: http://www.students.tut.fi/~alhonena...ga_1200dpi.jpg and as you can see, the rate of defects is so low it could be done in 35mm.

    However, if you are going to coat 35mm leader, you will have a problem with emulsion running to the perforations and off edges. Thus, you should use a bit wider film without perfs, then cut it down and perforate after coating. I have presented an inexpensive way to perforate 35mm with "good enough" quality for still film use: http://www.apug.org/forums/forum205/...rate-35mm.html

  4. #4
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    kb3lms,

    I hesitate to step in with an opinion, because I really do 'get' wanting to pursue a tough path, but...here I go anyway with an opinion.

    35mm is as hard a thing to manage in the handcoated biz as you can get. And, in the beginning it's not the right thing to be concentrating on. Learn to make an emulsion first. Make a lot of them, one after another. Fancy will follow from practice. Even if you don't want to be a 120 format photographer, old and not-so-old 120 cameras are available for a song. It's very easy to get the spools and backing paper. It's big enough to be easy to handle and small enough that you get a lot of bang for the buck. The money you save from experimenting with something very likely to work well for you will pay back the cost of the 120 gear in about a day (well, maybe a slight exaggeration, but only slight )

    Also, I'm not familiar with the 35mm material you reference, but it's important to determine if it's polyester or acetate. Wall's formula is very good, but it only works with acetate film, and then with a fair bit of flaws by modern film standards. My suggestion for you is to start with commercially subbed film. More info here: http://www.thelightfarm.com/cgi-bin/...tent=28Nov2011

    This is a great time to get started with diy emulsions. PE's book and DVD are sure to be great resources. And, of course, I'm also partial to The Light Farm. And, old books. And APUG. But, at the end of the day, what's really important is just digging in and getting started. OK, enough preaching and cheerleading from me. Best of luck and fun!

    d

  5. #5
    Photo Engineer's Avatar
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    Another problem that may crop up is the fact that most emulsions available ready made or do it yourself from formulas, are rather coarse grained and best suited to MF or LF and not 35mm. Grain and sharpness may then be a severe issue for you.

    PE

  6. #6
    dwross's Avatar
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    Actually, diy emulsion grain can be almost invisible. Unfortunately, the conflicting issue is then slow speed. I don't think it'll ever be easy to make artisan film that has both the speed and fine grain of the most modern commercial films, but I also don't think that will be seen as problem by folks wanting to roll their own.

    hrst: you can almost eliminate the wrinkles in subbed acetate by sandwiching the film between two sheets of 1-ply mat board (or similar) and applying a warm clothes iron, followed immediately by cooling under a weighted surface. It takes just a bit of experimentation to get the right temperature, but it does work. Having said that, I look forward to the next round of your corona discharge experiments!

  7. #7
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    Denise, you are correct. You might get good grain and sharpness in 35mm but at a severe price in speed. If you want decent speed, then you pay the grain price.

    Also, I am working on home brew high speed emulsions, but so far the results have not matched expectations. The best is about ISO 100 with a 1 micron grain. I know that I can do better, but it will take time.

    PE

  8. #8
    hrst's Avatar
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    Our ISO25 was very fine-grained, comparable to traditional ISO100ish films like Plus-X or APX100. So, you lose "only" two stops by making your own, old-style emulsion compared to modern commercial products. 2 stops only, it's not so bad, completely usable!

  9. #9
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    PF's subbed melinex works very well, and it comes in 52" wide segments which is nearly the length of a 36 exposure roll of 35mm.

    http://stores.photoformulary.com/-st...nex/Detail.bok

    You could cut it into strips and then devise some method of perforation like hrst. Just a thought...

  10. #10
    hrst's Avatar
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    This product has been available all the time, but I have never bought it because I have thought IT'S TOO EASY, it feels like cheating. But maybe it can be bought with an excuse that you first practice making just emulsions and want to coat easily for time being. Then, later, you can start making your own acetate from your own cotton field. Maybe I should place an order.....

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