White or gray, and smooth or rough screen?

Discussion in 'Home Theater Projects' started by Bart_R, Dec 26, 2005.

  1. Bart_R

    Bart_R Stunt Coordinator

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    Hi everybody,

    I asked this question in another thread as well, but I didn't get a whole lot of feedback (hmm, maybe Christmas has something to do with it... [​IMG] ), so that's why I'm dedicating a separate thread to the issue...

    I'm pretty much set for my ht. I ordered a Panny 900, got myself a nice framework, and also a piece of blackout cloth for the screen itself. However, there are two sides (literally and figuratively) to this screen, a white and a gray one. I can make my room very dark, only my walls are (still) white. So, I'm somewhat leaning toward the gray. However, in the (near) future I might paint my walls black, so the white would be better (or not?).

    So, my first question is: is it better to have a gray screen in a fully dark environment or a white screen in a not completely dark environment?

    Furthermore, the sides do not have the same texture. The gray side is more smooth, will the white side is (consequently) more rugged/rough looking. Which would be better?

    Thanks for any advice you could give me...

    Regards,
    Bart.
     
  2. Dave Poehlman

    Dave Poehlman Producer

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    I'm no screen expert, being a RPTV'er... but, as I understand it, most people that go with a gray screen do it to improve the black levels in the picture. So, I suppose it depends on your projector's levels.

    As far as rough/smooth. I suspect the white side is rough to avoid "hotspots", while the gray is slightly less reflective and less prone to "hotspots"... that's why it's smoother.


    ** that second answer is mostly a guess. [​IMG]
     
  3. Greg Monfort

    Greg Monfort Supporting Actor

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    Greets!

    It depends on the room's ambient light and how much light either the projector can uniformly 'throw' on the screen and/or increase the screen's gain at the ideal footlambert measurement to offset it. IOW, a picture's 'black' level can only be as deep as the screen looks without the projector on, so obviously the potentially deepest level obtainable is either in a room with zero light to reflect off it or the projector has enough candle-power to get the desired white reflectivity from a matte black screen.

    LCD projectors use to require relatively high gain screens, but I haven't kept current for some years now so don't know if that's still the case.

    Regardless, even flat white surfaces reflect some light, so I recommend at least either painting the screen wall with a dark matte flat color or cover it with dark matte drapes or material to increase contrast somewhat and use whichever side best matches Stewart's, etc., screen gain recommendations. IOW, if they recommend low gain (1.0-1.3) for LCDs, then use what looks darkest at the lowest light setting with it held up against the wall, and vice versa for higher gain.

    Of course, unless you're very lucky the overall picture quality typically won't be anywhere near optimum even once properly aligned, but judging by how many folks use/recommend blackout cloth for DIY screens, it's apparently not off enough to be a big deal in many cases.

    As always though, YMMV. [​IMG]

    GM
     
  4. Leo Kerr

    Leo Kerr Screenwriter

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    Modern LCD screens do not require a high gain screen. If I had to estimate, I'd say that my screen material is a .7 gain, with an open weave, meaning that somewhere between 60-75% of the light does not come back to the viewer (a large percentage doesn't even hit the screen material.)

    Unless you're relatively far from the screen, I'd suggest you want the smoothest surface you can get. If an individual pixel is the same size as the 'grain' of the coarse side of the screen, then either side should work.

    (My DIY screen uses a piece of stretched gray cotton fabric, with a loose, ~25% "fullness" black terry-cloth-like material ~3" behind it as a light sink for the light not handled by the screen itself.)

    Leo Kerr
     
  5. Bart_R

    Bart_R Stunt Coordinator

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    Thanks everyone.

    I received my Panny 900 yesterday and I'm now simply hanging the cloth over my frame in order to test out each side. I have done the white side, which looks very good, except for some instances in black scenes where elements blend too much. In that sense I suppose the gray side will work better, but I have yet to find that out.

    I'm very impressed by the details in the close-ups and the natural flesh tones. And of course the panoramic shots in films like LOTR are terrific on a big screen with a cinemascope ratio.

    It's a bit of a catch 22 in a way, since right now I suppose the gray side will be better, because of my white walls. Yet, I plan on painting the walls dark/black soon, at which point the white side might be better again. I guess I'll just have to figure this one out by myself.

    Thanks for the advice [​IMG].

    Bart.
     

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