Diffusion Fabric Question

Discussion in 'Lighting' started by Grif, Nov 18, 2010.

  1. Grif

    Grif Member

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    Building some DIY light boxes. (starting with one "big" one). Which of the "white" products at the local fabric store seem to do the best job as a diffuser? It'll be a combination of PVC pipe and the white foam board for the back.

    Shopping around, they have some poly, white "stiffener" products, more of a mat like material, and lots of nylon looking products.

    Opinions?
     
  2. Ian Grant

    Ian Grant Subscriber

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    You might look at the plastic rod and fittings used to make kites, much lighter but with very good rigidity. I've seen white translucent polyester cloth in many stores that's very similar to the material used commercially.

    Somewhere I have a 20 year old article on making a DIY diffuser and that used then kite parts, they aren't expensive.

    Ian
     
  3. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  4. Robert Hall

    Robert Hall Subscriber

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    Silk is a good bet, I like some of the rayon materials, one thing to remember is if you shoot color, the color of the fabric will have a balance effect on your output. Even over time the fabric color changes and may yellow.

    I have used a rubber backed fabric for the outer cases and an inner baffle of silk helps to further diffuse the light source.

    For what it's worth.
     
  5. Grif

    Grif Member

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    There was a good thread on a black thin product folks were using as one layer on diy bellows, I'll go look it up again. I wonder what makes silk the good product? I do have a very nice small umbrella or two of silk from the old days, I'd forgotten all about them.

    And kite parts,,, what a great idea! I was thinking about my tent poles with bungie cords internal,,, but they're not giving them away for anything like what I was willing to spend.

    So, the inner baffle, at the outside front of the light box, there's a panel of silk,,, then a foot or so inside, there is another panel of silk making a chamber? That makes sense, and I like the roll it up feature with a fabric build rather than the foam art board.
     
  6. Mike Wilde

    Mike Wilde Member

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    look up 'Dean Collins Tinker Tube' - I have a pdf but it is 3.5mb, so a bit big to post here. All sorts of good ideas to get yiu started in that document.
     
  7. Grif

    Grif Member

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    Fun video,,, wonder what the color temp of on of those quartz work lights is?
     
  8. Grif

    Grif Member

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    TinkerTube it is. I've been using PVC pipe as an orchardist since I was a kid. Keep glue and primer in little six packs on the shelf, and I'll bet I've got 30 lbs of fittings and 2 or 300 feet of 1/2 thru 1 1/2 left overs.

    PVC stand for my RC plane at the flying field, the stuff seems to show up everywhere.

    So,,, why, with every new PVC pipe project does my stash of left overs just keep getting bigger, instead of shrinking??? Kind of like screws nuts and bolts I guess
     
  9. John Koehrer

    John Koehrer Subscriber

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    About 3200k
     
  10. Grif

    Grif Member

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    Well,,, so there, then. I think I've even got the filters for daylight film.

    Does the new color negative film really need to be filtered to get good results from 3200 light? Seems like I've read it does ok without any help.
     
  11. greybeard

    greybeard Member

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    So,,, why, with every new PVC pipe project does my stash of left overs just keep getting bigger, instead of shrinking??? Kind of like screws nuts and bolts I guess

    That's because there are male and female fittings stored together. Ya gotta keep them separate...

    Same thing happens to bolts, although it's not a problem if the nuts are castellated.

    (And for what it's worth, I found better diffuser material at an outfitter/sporting goods place than I did at the fabric store. It is apparently used for windows in nylon tents.)
     
  12. Grif

    Grif Member

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    How's that go? No, No!!! not without a Washer!!! ;-)

    Anyway, I'll look for the other stuff. We don't have anything like that around here,,, Seattle is likely the closest at 3 hours one way, but I'll bet the big brown truck would have it.
     
  13. quantumhelp

    quantumhelp Member

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    Daylight negative color film, or for that matter transparency fill is balanced for around 5500 K. 3200K lights are way off and you would get a reddish orange cast.

    Even black and white film would react differently to 5500K and 3200K colored light sources.
     
  14. Grif

    Grif Member

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    Filters,,, Been around for years.
     
  15. olleorama

    olleorama Member

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    I built a soft box and octabanks with a shower curtain from IKEA, it was 29 SEK or $4.3, size 2x1,8 m, couldn't find any fabric with such a low price in the fabric store. You could probably find a cheap shower curtain in any low priced shop around your parts. Just make sure it's white and not some kind of off-white.
     
  16. Lee L

    Lee L Member

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    You're about 7 miles or so from the Jo-Ann Fabric store in Yakima, 3702 Tieton Drive.

    Ask for white rip-stop nylon or sport nylon. The rip-stop is thinner and allows a bit more light through. The sport nylon is a little denser and provides slightly more diffusion. The rip-stop is 60 inches wide. I believe the sport nylon is the same width. Both show online as $6.99 per linear yard. Both are recommended for diffusion panels. I sometimes space two layers of rip-stop a few inches apart to get more diffuse shadow edges.

    PVC is cool. I've used it myself. But I'm in the middle of designing some stands, free-standing diffusion panels, booms, reflector supports, etc. with a method called gridbeam. (google it) It's reconfigurable/reusable and very flexible. With the free Google Sketchup CAD program and a set of CAD gridbeam components available free from the Sketchup 3D Warehouse, you can get started designing on the computer before you build. If you have some woodworking tools, especially a drill press, I'd recommend going this way.

    If you decide to go with gridbeam, PM me about online sources for the 'joint connector bolts' that wooden gridbeam uses. I've found what I think are the best prices, bolts and nuts from two different sources.

    Lee