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Filters to improve contrast

Discussion in 'Projectors, Screens & Video Processors' started by maj74, Aug 6, 2002.

  1. maj74

    maj74
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    Hi,

    I have a new Sharp M20X and I'm more than a little pleased with it!. :D

    I have an Icestorm 5 screen which has improved the black level. (the contrast in the picture was already excellent!)

    I would though like to try and get that black level a little darker if possible (hey, who wouldn't?!) and with the 1500 lumens that I have to play with on the M20X thought that I should be able to add a filter that people keep mentioning to improve the black and contrast.

    If so, what filter am I after. I think it's got 'Hoya' in the name but I don't know if that's the make, and if so, which filter is it? does it have a number that I can go into a shop with where they might know what I'm talking about!!!

    Any info greatly appreciated.

    Thanks

    Martin
     
  2. LV426

    LV426
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    Use of a filter to improve contrast is normally mentioned in the context of Sony PJs (eg VW10, VW11). The principle is that, because of factors like the exact colour of the light from the lamp (and possibly other factors in the optics), the RED LCD panel always has a higher gain setting than the others to get the right balance.

    So, the theory goes that, if you add a pink filter to the PJ, you can increase the gain on the other two colours (blue, green). The net effect is that the pink filter darkens the black, and the increase in gain on green and blue restores the intensity of other shades up to white. You get a greater difference between black and white ie more contrast.

    It only works if the gain setting for one colour is greater than the other two. You find this out (on the Sonys) by entering the service menu and looking at the three gain values.

    I have no idea whether the M20 is the same in this respect; it may not be. If the individual gains are similar and/or not separate;y adjustable, then a coloured filter won't work.

    You can add a neutral density (grey) filter. This does NOT increase contrast. It reduces brightness evenly throughout, making both blacks and whites darker ie a similar effect to using a grey screen.
     
  3. chic

    chic
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    the filter most people are using with the panasonic is the
    HOYA FLD filter it has a 55mm thread and can be bought from jessops, although they may have to order it for you.

    seehere

    this filter tones down the green with the panny dont know how it would work with your pj
     

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