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Why was 6500k chosen for colour temp?

Discussion in 'Projectors, Screens & Video Processors' started by cybersoga, Jan 18, 2004.

  1. cybersoga

    cybersoga
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    Why was 6500k chosen for the temperature of white/grey scale? Is 6500 equal amounts of red, green and blue?
     
  2. RichardA

    RichardA
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    6500K is a colour temperature for white because it is the same as 'North Light' i.e. the colour of daylight in the Northern Hemisphere - a TV set will look similar to the outside world.

    Of course that isn't the only colour of white, Cinema projection is balanced for 5400K - that's because it's the natural colour temperature for xenon arc lamps.

    Well that's the potted version - there is a lot more to it than just these points, (like why the normal temperature isn't 6500K but actually 6504K otherwise known as D6500 or illuminant D !)

    Hope this helps.
     
  3. cybersoga

    cybersoga
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    I really should get my plasma calibrated, i've done they best I can with my own eyes, but i'm a bit stuck with regards to colour temperature without the right equipment. My Plasma has settings for Cool, Normal and Warm, as well as two custom modes. If I put on a IRE 50 test pattern, cool looks blueish, warm looks reddish and normal is somewhere in the middle. I've had it set to normal for most of the time, but i'm wondering if Warm would be closer to 6500k.
     
  4. cybersoga

    cybersoga
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    I just found the information I was looking for on the back of a schematic diagram that came with the plasma - it has the service menu adjustments (although it's in spanish - not sure if the dealer was meant to give me that, it was in the bag with the user manual!) assuming it's been calibrated properly in the factory, Cool (High) is 10000k, Normal (Middle) is 8000k and Warm (Low) is 6500k.
     
  5. jmack

    jmack
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    cyber would you mind posting your settings,

    as i use the warm settings, would be intrested to try other settings.

    cheers
     
  6. cybersoga

    cybersoga
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    I have a different plasma to you so I dont think it would be a lot of use, cool, normal and warm are going to give a different colour temperature on different plasmas, and on my own plasma they can all be adjusted in the service menu so even 2 plasmas of the same model won't nessisarily be the same colour temp on the same setting. By the factory, Normal is set to R +6, G 00, B +24, Warm is R +24, G 00, B -14.
     
  7. StooMonster

    StooMonster
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    Isn't 6,500°K the average temperature of daylight in Hollywood at midday? Or is that just some techie myth?

    StooMonster
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    If you visit your friendly local Newsagent and get this months
    Stereophile Guide to Home Theatre you will find the fist part (and it's LONG and Technical) of an article about how we perceive colour through our eyes and why /how Colour TV works. They address 6500K etc in it.

    As for factory set 6500K. Well the issue is that even 6500K is not correct. Thats why Richard mentioned D65. I've measured a few projectors out of the box that are close to 6500K but they are miles too green.......read the article and all will be revealed.....

    Gordon
     

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