help with screen gains, and material

Discussion in 'Projectors, Screens & Video Processors' started by jkoc, Mar 8, 2005.

  1. jkoc

    jkoc
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    i'm looking to build my own 16:9 screen.

    the characteristics of the room is that there is a lot of ambient light. i can only acheive perfect darkness only at late nights (obviously) but i would like to have the ability to view movies somewhat respectably on the projector in early evenings when the sun is just setting and its only slightly dark.

    should i be getting a high gain screen? 1.3? or a 1.0? or a low gain 0.8?


    also, what do you guyys think about DAZIAN material? example:
    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48655&item=5756718863&rd=1

    it is 1.3 gain.
     
  2. davehk

    davehk
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    A high gain screen will be more visible that a low gain screen, but over a narrow viewing angle. SO you need to think about the geometry of your room - screen width, screen to seating distance and seating width, and the light output of the projector. It's also important that you don't have an (uncovered) window at the back of the room - since a high gain screen will reflect that better too. Similarly you don't want one behind the screen as light from that will scatter inside the eye and cause a significant loss of contrast in the perceived image.

    Then look up the manufacturers information about the various screen materials and you should be able to work out the effective intensity at the viewing positions.

    I don't know myself. but I expect someone here can tell you what effective intensity is needed for reasonable viewing in a given ambient light level.
     
  3. jkoc

    jkoc
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    i have a rectangular room about 19ft in length. the viewers are directly in front probably at a span of about 60degrees from the center of the screen. there are windows on the left side of the screen, as well as the left side of the projector (but i anticipate curtains ssoon). over to the right, there is a light coming in from the stairway windows as well as from the slide glass door from the kitchen -- sigh. -- i do anticipate curtains there, but it will be moreover translucent curtains.

    needless to say, lotta ambient light. i dont expect to watch any movies in the daytime, but i'd like to be able to watch around sunset where there is still some light outside.

    the projector is an infocus x1. projecting approx 100" 16:9 diagonal with minimal zoom usage and minimal digital keystoning.
     
  4. Screen Scene

    Screen Scene
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    Hi ,

    have a look at this info , I hope it helps. :D
     

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  5. keyser

    keyser
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    Screen gain sounds good in theory, but I´ve found most all screens with any gain to have sparkly artifacts and some have a noticable textured finish. Get a sample of any material with gain before you buy. I thought there was room for a big improvement with my 1.0 white material, but all samples I´ve gotten have looked worse.
     
  6. Screen Scene

    Screen Scene
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    Hi ,

    I agree that the 'sparkle effect' can be seen on some surfaces , but it is the scatter of light that makes the material improve the reflective light , or gain and Pearlesant finishes are what Cinemas use between 1.4 and 1.8 gain.

    It is also critical to viewing distance that the right gain surface is used.

    A 1.8 gain surface should not be used under 4-5 meter viewing distance.

    But on the texture , there have been some great advances with water based gain paints and these do not leave the finish textured, but smooth.

    I have found that some Silver screens can do both , improve gain and contrast.
    Regards
     
  7. Joe Fernand

    Joe Fernand
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    jkoc

    If you have the projector and if you have a white surface you can project onto you'll already have a pretty good idea what most conventional surfaces will do for you when the ambient light level is high in your room.

    To achieve what your trying to achieve probably requires two surfaces - one for Daytime and one for Evening; as others have pointed out the specialist surfaces that enable Daytime viewing are not that great for Night time viewing.

    So a 1.0 to 1.3 surface for Evening viewing and possibly a 'Silver' surface for daytime viewing - not sure if VuTec or any of the other 'Silver' surface manufacturers supply these surfaces 'on the roll'.

    See http://www.vutec.com/vutec/silverstar.pdf

    Best regards

    Joe
     
  8. keyser

    keyser
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    I noticed a sparklie effect with the cinema vision, high contrast cinema vision and video spectra 1.5(which also had a texture to it). It bothered me too much for me to have a screen with any of that material, and weirdly enough I didn´t find any of them noticably brigther than my white screen, escpecially the HCCV and the CV, which had a champaigne coloured finish which ofcourse made the picture look a bit more yellowish. The sparklie effect became noticable to me way before the screendoor(with my matterhorn projector).. all of my friends said the same thing as me.
    I also have samples of the silverstar and a high power. The silverstar didn´t have a sparklie effect that I noticed to much(but I have really spent little time with it), but it´s viewing cone was way too narrow for me(got pretty dark at 45* which my widest seats are at). The high power also didn´t have any noticable sparklies or texture, but it´s cone was EXTREMELY narrow, brighter than my white in only 1-2 seats, but unlike the silverstar it never get noticably darker than my 1.0 at wide angles, which is weird.

    I was sure that in my relatively bright coloured room I could find a screen better than my white one, but all the samples have looked worse to me. But it´s hard to judge some features of the samples from how small they are, like how well they do with ambient light and how they´d look if wasn´t directly comparing them to an 1.0 white screen. But that beeing said I found the sparklies so bad that I won´t even bother to check it out any further.

    I probably wouldn´t notice the sparklies if I´d sit further from the screen, but what´s the point of a projector if I don´t want to sit kinda close to a huge screen?
     
  9. jkoc

    jkoc
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    i ended up buying a da-lite permwall series 92" 16:9 high contrast cinema vision screen....

    i really like this screen -- works well in some ambient light actually... the colours dont seem as washed out as with my matte white screen.
     
  10. jkoc

    jkoc
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    does the silverstar actually work... 6.0 gain???
     

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