a quest for opaque material

Discussion in 'Camera Building, Repairs & Modification' started by David Lyga, Mar 31, 2014.

  1. David Lyga

    David Lyga Subscriber

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    Some time ago I got a bulk roll of 35mm film. I cannot remember which kind it was but it came with a leader of a few feet that was black, plastic, and completely opaque. I am glad that I saved it and now have about two feet of it left.

    I use this material for various purposes. For example, I have a camera that I have converted to half frame (by running the film through in the opposite direction) and that thin, opaque leader has allowed me to restrict the film aperture gate to the dimension I wanted, 18mm x 24mm. Also, the smallest negative carrier I have is a full frame 35mm, so this material has, again. allowed me to cover that film gate in a way that will not allow extraneous light to enter upon the baseboard.

    The material I seek has to be both opaque and thin (no thicker that post card stock, preferably somewhat thinner). It does not have to come in 35mm width; in fact sheet form might be even better. I have checked with local art supply stores but the opaqueness is really the problem here, in conjunction with the required thinness. I wonder if there is even a very thin metal that might be able to be cut, but I think that plastic might be the best possibility here. Aluminum foil, as well as the plastic that light tight bags are made of, both lack the rigidity that I seek. Black construction paper is not wanted because of the dust problem that will ensue.

    This search has been harder than I had anticipated. What was that leader made of that caused complete opaqueness? Perhaps the solution to this problem will be readily apparent to some reading this. In advance, I thank all. - David Lyga
     
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  2. ann

    ann Subscriber

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    Have you checked into use "rubylith", it might do the trick.
     
  3. Truzi

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    Just a quick thought - can you sacrifice some film? Would it be opaque enough after development? Of course my first thought is to search online for 35mm leaders, but most I've seen on ebay and the like were not opaque.

    I also wonder if you can find some thin metal at the craft supply stores you visited - perhaps a hobby shop that has a lot of RC or Slot cars (you know, the old-style slot shops.) Perhaps even an adhesive Mylar sheet? When I was younger, thin sheets of metal were common at craft stores, but I don't know if they have moved away from that.

    Fabric store?

    Another stupid idea... a piece of kodachrome? Would the remjet survive any abrasion from your intended use?
     
  4. David Lyga

    David Lyga Subscriber

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    No Truzi, developed film is BLACK but not quite opaque. Shine a flashlight through it to see what I mean. Fabric is too lacking in rigidity. The Kodachrome is an idea and I might have a roll stored away. But that is not really enough.

    There has to be, from somewhere, plastic sheeting that I need. Who made that original leader: a wizard???

    ann, Rubylith seems to not be the answer as it does not seem to be opaque. See this: http://www.dickblick.com/products/ulano-rubylith-masking-film/#photos - David Lyga
     
  5. gorbas

    gorbas Subscriber

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    David, there is thick black aluminum foil used to block light (usually on movie sets) called Black wrap. It's totally opaque and has right thickens. The only possible problem with it is it's matt surface, if you rub something over it for long time eventually paint will come off. Its sold in rolls 1 or 2 feet wide and few feet long. I can cut you one sheet and send you for test. Goran
     
  6. Tom1956

    Tom1956 Inactive

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    Good luck on that David. I looked for some back in the 80's and gave up.
     
  7. gorbas

    gorbas Subscriber

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    As for using processed film for masking, you have to use graphic art film developed in Kodalith style of developer and it will be totally opaque. Nikon CoolScan 8000 has negative masks for it's glass negative carrier made of exactly right material you are looking for. But where we can find it?
     
  8. jp498

    jp498 Member

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    How bout chopping up some of the black bags used for photo paper.
     
  9. Perry

    Perry Member

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    Google "industrial plastics suppliers"; they have all manner of nylons, delrins and other plastics of various colors and opaquenesses; they also come in numerous thicknesses and stiffnesses

    Hobby shops stock various metals i.e. steel, stainless, copper, brass and aluminum sheet of various thicknesses and stiffnesses; many of which can be cut with standard scissors

    Perry
     
  10. ann

    ann Subscriber

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    The rubylith we used in alternative printing certainly blocks light for over 30-45 minutes.
     
  11. David Lyga

    David Lyga Subscriber

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    jp498: Again, the material used for black bags is too unstable: I need something that will not wrinkle and will stay flat (unless I introduce a slight curve like in the camera for half frame. I wanted to see if I was really stumped and it does look like this type of material is not easy to find.

    Perry: Yes, I am going to work Google to the extreme. I just thought that there was something simple that I could pick up locally and be done with it. Google will be my last resort.

    gorbas: TOTALLY opaque? I do have some Kodak ImageLink that I could process in Dektol for five minutes. But I will have to check whether really black is TOTALLY opaque. Besides, with time that emulsion will allow light to bleed through as it inevitably gets scratched. Better for a material to be opaque throughout.
    - David Lyga
     
  12. dancluff

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    I am unsure if it is stiff enough or durable enough but the backing of a 120 film roll is opaque, cheap and going to be thrown in the garbage anyway. Perhaps some of the backing paper glued or double sided taped to something stiffer might work.
    Dan
     
  13. David Lyga

    David Lyga Subscriber

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    Yes, Dan, that is a possibility but I had wanted to shy away from having to have TWO layers of anything. It is interesting how this quandary stumps all. - David Lyga
     
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  15. E. von Hoegh

    E. von Hoegh Member

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  16. dancluff

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    These places seem to sell 0.0125" sheets of black plastic shim stock but I guess there is no way of know if they are fully opaque. Also the thickness may be pushing your requirements.

    http://www.customgasketmfg.com/DieCutGaskets/PlasticGaskets
    http://www.use-enco.com/1/1/87775-sheet-black-plastic-shim-stock.html

    McMaster-Car also sells a polycarbonate 0.0125" thick shim stock that is black, but again no mention of opacity.
    You have likely found these sources yourself already and they are not local. However shipping from McMaster-Carr is so fast it seems they ship the product before you even buy it.
    Good luck with the search
    Dan
     
  17. snapguy

    snapguy Member

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    shim

    I wish I could shim like my sister Kate....as the olde song goes.
     
  18. cliveh

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    David, there are thousands of examples of opaque materials that will fit your criteria. All metals and opaque plastics as thin material for starters.
     
  19. snapguy

    snapguy Member

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    Seriously

    I Googled "35mm film with opaque black leader" and was referred to motion picture film leaders. Ebay has it for $15 for 100 feet.
     
  20. gorbas

    gorbas Subscriber

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    David, I do not have any experience with Kodak ImageLink film. Using other high contrast microfilm with regular positive developers never give me maximum density as Kodalith film developed in Kodalith developer. It has "bullet proof" Dmax. When you look thru processed high contrast film processed in positive developer most likely you will see just filament of clear 60W bulb. With properly processed Kodalith you will see nothing.
    You can always turn "glossy" side of film on contact side so no scratches on emulsion side.
     
  21. Tom1956

    Tom1956 Inactive

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    David, bless ya, I think you get into as many projects as I do.
     
  22. John Koehrer

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    I'm assuming he wants to use it with panchromatic film. Maybe not.

    carbon Fiber? Some hobby shops. Various thicknesses and widths.
     
  23. Truzi

    Truzi Subscriber

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    Would an old lens cap be opaque and thin enough?
    Some old computers have metal shielding inside that may be thin enough.

    I had checked some Rollei Retro 400s plastic 35mm canisters, and they appeared to be opaque enough for short-term storage - though I filled them in low light, and stored in a drawer; I don't think it could be easily flattened.
    Hmm, for that matter, you might be able to flatten and cut up an old 35mm cartridge - might even get some for free from a drugstore minilab.

    Towards that end, you can easily cut and flatten a pop (soda) can.
     
  24. Bill Burk

    Bill Burk Subscriber

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    You only need a density slightly over 2 to create a negative carrier, because a highlight with a density over 2 on the negative will print paper white. But continue looking for opaque materials...

    The paper backing from Kodak 120 films easily exceeds the maximum density readings of my densitometer (Macbeth TR524). Also I think shutter curtain material would be good. I measured a generic dark changing bag and its rubberized nylon fabric also exceeds the maximum density of my densitometer. I was comparing the material to other material because I wanted to make a lightweight changing bag. But in the end, I found nothing better and I took the changing bag with me despite its relatively heavy weight.
     
  25. Ross Chambers

    Ross Chambers Member

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    Careful, in film cutting rooms "opaque" was quite a loose description, in fact we picked the term up from English trained editors and what they called a rol of "opaque" and used for start footage of a cut reel was white and not anywhere near light proof. White so that roll numbers etc could be written on it. Usage of the term may vary of course
     
  26. Tom1956

    Tom1956 Inactive

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    After following this thread, my mind still is set on the thickest mil rating of the black polyethelene sheets in perhaps 12x20 foot size at the Lowes home improvement store. They're sold folded and creased, but the uncreased areas are very flat and smooth. And this stuff has a very high opacity.