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Colour temperature on a Barco Graphics 808s

Discussion in 'Projectors, Screens & Video Processors' started by Tim Cooper, Apr 13, 2002.

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  1. Tim Cooper

    Tim Cooper
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    Hi Chaps,

    Just out of interest what colour temp do you Barco owners run?

    I found that on certain films (Gladiator was the worst) the skin tones at the 6500k setting made dear old Russell look like an ompa-lumpa,very fake tan look about him,i know the film had a yellow tint to it...but....I then switched the colour temp to 9300k what a difference flesh tones especially are more realistic.
    To me it looks much better,switched back to 6500k... no don't like it, so I left it at 9300k:D
    Are there any issues running at this temp?
    Do you think the the 6500k settings where adjusted to the previous owners taste i know you can adjust for each colour to suit taste but i just left well alone:)
    System
    Barco 808s:
    Running @ 1280x720 72/75 hz
    Brightness @ 42
    Contrast @ 60
    HCPC:
    Radeon 7200 graphics
    Powerdvd 4 all video adjustments set to default all adjustments made via the ATI overlay.
    Thanks chaps
    Tim
     
  2. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The colour temp setting is likely to be incorrect at all settings on your unit. There are many reasons for this.

    1: Dependant on the type of programme material used in the past some tubes may be more worn out than others affecting the relative light output levels.

    2: The beamspot focus may be different on this installation compared to last time resulting in different light output levels.

    3: The room decor may affect the colour balance of the light being thrown back on to the screen.

    4: The ancillary equipment is different.

    There's probably even more than that. Bet Roland could add some. So the only way to get it accurate is to have someone pop around with tool cabable of measuring the temperature and setting it correctly.

    Gordon
     
  3. Paul D

    Paul D
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    I agree with Gordon about your settings being out, the 9300k setting should make everything look very blueish.
    Having a ISF type calibration is a must, as the difference to shadow detail and flesh tones is amazing. I used to think that as long as the picture looked OK, then i wasn't bothered if the colours were true to life etc.
    But it's not just about making them true to life, it helps with contrast and the 3Dness of the picture.
    It will release detail in the picture you didn't even know was there!.

    Now if i can just kidnap Gordon next time he's passing my way! :D
     
  4. Tim Cooper

    Tim Cooper
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    Hi Chaps,
    Aren't the colour settings preset?
    You can alter custom red & blue gain,custom green gain,custom R & B cut off,and lastly custom green cut off.
    Am i right in thinking that if you were not satisfied with the preset colour settings that you altered these settings until you were satisfied.
    The colour temp at 9300k gives me really good results without the blue tinge (not very blueish) what's going on then??????:confused:
    The picture at 6500k definatley has a yellowish tint, more at 4900k.
    Have those custom settings have a bearing on the preset colour temps???
    Gordon:
    You mentioned wear on the tubes would this give me a yellowish tint on a PJ that's only done 2300hrs i keep my contrast settings relatively lowish @ 60 i've heard some adjust theirs up to 75-80
    Could i check for wear/burn without removing the lenses??
    Also where can i find an ISF cal engineer in Essex i thought that you where the only one (that mattered) does Roland do the cals or does he rely on experience & eye.
    Care to reply to this thread Roland? ;)
    Thanks again
    Worried from Essex
     
  5. Tim Cooper

    Tim Cooper
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    Just checked the CRT's using a halogen desk lamp the crt faces look fine no wear/burn the phosphers look uniform in colour right out to the edges i take it this is ok?
    Thanks
    Not so worried from Essex:D
     
  6. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Tim

    The thing's are pre-calibrated before leaving factory so that the temperatures are correct in their lab. However, if the G2 pots move or the focus pots or anything then the amount of light coming out of each gun will change altering the colour temperature. Indeed the earths magnetic field will be different in UK than in Belgium so that the beamspot size or shape may alter...even this will change the actual measured temperature at their pre-set. Not by huge amount I'd hope though.

    The pre-sets can be altered with the bias and gains as you note. You can even have a play yourself to see if you can get it better. Just remember to keep a note of everything before playing around.

    I go to England lots... Just ask Nick Beecham and his glorious SDI'd Marquee7500! I'll probably be down in just over a week. Roland has the same video analyser that I use. I trust him to use it properly!

    Lastly there doens't have to be burn or wear on the tube face for the light output to have dropped more on one thatn the other through use.

    Gordon
     
  7. Tim Cooper

    Tim Cooper
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    Thanks Gordon for the reply just one bit i didn't understand:

    I'm always getting my wucking murds fuddled too :D :D :D

    I think i'll give Roland a call he's more or less local to me.

    Cheers
    Tim
     
  8. Roland @ B4

    Roland @ B4
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    Most likely is that your G2's are not set correctly.

    But silly things like bad cables and connections can make this kind of differnce too.

    I never use the presets on the barco and even Barco admit that they are not accurate.

    It sounds like your Blue tube is under performing. find a bit of black video and pause it on the DVD player. turn the brightness on the PJ down until the raster is just still showing. It should be the same brightness (glow) on all three tubes.

    Are you happy to get your hands inside the machine?
     
  9. Jenz

    Jenz
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    Mine is ISF calibrated. The difference between before-after was fairly astounding. (in fact I retain a memory block to demonstrate it!).
     
  10. Tim Cooper

    Tim Cooper
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    Hi all,

    Thanks for all the replies :)

    Roland:

    I'm going to investigate the vga cable first from my hcpc,it was only meant to be temporary (standard vga cable with bnc's) but the picture was so good i never got around to buying an expensive one :blush:

    I did the black out test, the green is brightest followed by the red & blue both of which are approx the same brightness.

    Out of interest what vga cable would you recommend & do you recommend connecting the vga at the 9pin connector or the BNC'son the PJ?


    Dont' mind going into my PJ if i get expert instruction (hah honourable master... wax on wax off...paint on paint off) :D :D :D

    Thanks for the reply Roland speak to you soon

    Tim

    P.S Hi Neil how's it hanging:D :D
     
  11. nfordenfield

    nfordenfield
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    Is it expensive to get an ISF calibration done?

    Are there improvements that I can do or am I just gonna make things worse?

    Must admit that although to the untrained eye picture is showing a 3D effect, colours do seem to be lacking punch. Can't seem to get normal flesh tones, picture just seems too dark. More brightness just washes the black colour out.

    Don't want to drive pj to hard in the wrong direction.

    I have left the QS pro on factory settings and only tweaked the Pioneer 737 on sharpness etc(seems the best place to do this as assume still in the digital domain).

    Have used the THX Optimode to set up the contrast, brightness, so assume must be the actual colour mix/temperature.

    Have now hung dark blue drapes all around (not over the screen though) to improve darkest level. Even to the extent of applying black tape to all those annoying LED's on the amp/dvd etc. Read somewhere that a tweak was done on a blue tube to compensate the room colour?

    Any pointers greatly appreciated.

    Nathan
     
  12. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The Optimode doesn't have the patterns you may require to check whether the Quadscan is crushing white or clipping black detail( at least I don't think it has. Without seeing the installation it's hard to tell whether it's all OK or not....

    AVIA has moving bar patterns that may prove useful in this respect.

    Gordon
     
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