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Grey Screen stripes - Is it bad with you

Discussion in 'Projectors, Screens & Video Processors' started by DynamoDoug, Jul 5, 2002.

  1. DynamoDoug

    DynamoDoug
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    Hello,

    I'm just trying out a 2000 lumen 4:3 XGA projector with 400:1 contrast ratio on a matt white screen.

    I'ts great when using it for Powerpoint projection.

    However, when trying it on a DVD with a widescreen format, the picture has silvery grey bands as the format does not fill the 4:3 panel.

    It's so bad that I'm considering getting a Panasonic AE100 for DVD's as it has lower lumens out and higher contrast ratio.

    How does your projector cope with widescreen pictures, does it have grey bands where it ought to be black? Though mine, with the excesive 2000 lumens output, places them in the silver grey range.

    thanks
     
  2. DVDcake

    DVDcake
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    This would be a problem for any 4:3 projector although more so the more light output you use. However have you tried masking off the area of the screen where the bars appear with black material to reduce their reflection?
     
  3. DynamoDoug

    DynamoDoug
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    thanks I'll try masking the edge.

    Not having a grey filter on hand, I have tried looking at the screen through sunglasses, which does improve it.

    But I think I may be expecting too much!!

    I do aim to go out and get some plywood and paint it grey to see if that improves it. With 2000L, the light output the PJ is unbelievable when using it in the living room, it's like sitting in front of a searchlight.

    What is the output of your PJ.

    Are your backs a true black or tending to be towards grey?
     
  4. DVDcake

    DVDcake
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    I am waiting to recieve my PJ, a Panasonic PT-LC75. It outputs at 1200 lumens 4:3 format but also has a low light mode of 900 lumens. This is considerably less than your output.

    I will be using it for presentations and in a 13 by 8 foot bedroom so I am still a bit concerned that it will be too bright even on low mode. However another forum member told me they did not find the bars distracting due to the perfect picture geomatry and suggested the masking to me to begin with.

    I have no experience of grey screens, but from what I have read on other posts one might be able to help you and should improve your black level on the main picture.

    :)
     
  5. Comer

    Comer
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    I think that the image of some one sitting in the pitch black, watching a movie, popcorn in one hand, beer in the other and wearing sunglasses is hilarous :D :D :D

    Just goes to show, the lenghts we'll go to, eh?



    Conor
     
  6. RichardH

    RichardH
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    Remember that even with a 16:9 projector, when watching a 1:2.35 ratio movie you'll still get the grey stripes.
    I've been considering this for a while, and dreaming up all sort of Heath Robinson contraptions to address it (intending to have a fixed home made screen).
     
  7. Guest

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    The cheapest way to avoid the grey stripes is to ignore them, I mean really, even, if you switch between 2.35:1 and 1.85:1 you'll always get them, even on a 16x9 PJ. Focus on the awesome picture and not the stripes, it's just like with screendoor, watch the film not the Projector:)
     
  8. jrwood

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    The ideal lumens for a htpc projector is really about 800 lumens, but like you say its for presentation use. Anyway if I had that projector I would not get the Panasonic its best to try cheap ways of improving your setup at home with minimal cost.

    I have a 4:3 projector at home and use John Lewis Velvet which cost about £50 for 8 foot wide by about 4 foot deep for the top and bottom of the wall that my screen hangs on. This creates a 16:9 screen mask and improves the perceived contrast by at least 30% as the light overspill is 'soaked' up by the black velvet. It also has the advantage that it looks good having a screen surrounded with black velvet too!.

    The next part I would try is buy some MDF from B&Q, I would buy say two pieces of about 3 or 4 foot wide so that its easy to take home in the car. Pick up some ICESTORM 5 and ICESTORM 4 paint from the paint mixing department in B&Q and paint each of the pieces with a foam roller from Homebase. I would probably gives it two coats for a better finish although your seeing how it looks as you don't want white to be light grey with ICESTORM 4 ...but with 2000 lumens I think ICESTORM 4 might be a better choice to get really good blacks and improve contrast even more on the projector.

    Once you've temporarily hooked up both MDF mini screens on to the wall project some films on to them and see the difference, you might find that ICESTORM 4 is better for blacks but you need to check the white's in case they look grey. Checkout a lot of dark scenes like the beginning of the 'Gladiator' DVD and films such as Pitch Black, Planet of The Apes and a few others mentioned on these forums.

    Once your happy then order the largest piece of MDF from B&Q or from another retailer and paint it with the ICESTORM colour you found best. I currently use ICESTORM 5 with a filter with my projector and blacks are really black! and whites are almost white so I can live with that. Although I plan to try ICESTORM 6 and a filter with my projector in the near future just as an experiement but masking using velvet does help a lot to improve the picture quality even when watching 2.35:1 films.
     
  9. DynamoDoug

    DynamoDoug
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    Thanks to every one for their thoughts and ideas.

    Initially I thought that the PJ wasn't working too well.

    It's nice to know that it's inevitable, and a common problem with LCD PJ's.

    In theory, I did get the contrast better by moving the PJ into the playroom which is longer. So the screen is now twice the size (10 ft wide) it was in the first room. Consequently the grey has reduced, as the lumens per square inch has reduced.

    I will be constructing a grey screen with a black border.

    Thanks again
    Doug
     

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