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Advanced Calibration Techniques

Discussion in 'Projectors, Screens & Video Processors' started by cyberheater, Jul 9, 2005.

  1. cyberheater

    cyberheater
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    Right.

    I've gone as far as I can go using my eyes and AVIA / DVE and i'm ready to go the next step.

    I would like to calibrate my modded BenQ PB6100 and find out it's actual contrast ratio, lumen output and also determine how accurately it's tracking colour from 0 ire - 100 ire.

    At the end of the exercise I want to have a perfectly calibrated projector even if filters are required and max out it's contrast ratio.

    So. What do I need and what are the techniques.

    I suppose I should start with a light meter. What spec etc will do?
     
  2. Gary Lightfoot

    Gary Lightfoot
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    Hi Cyber,

    A light meter is fine for lumen and contrast calculations, but for colour calibration you need a colorimiter and software to translate the readings like Colorfacts or OpticOne. SMART III is a cheap alternative but it doesn't see light in the same way as the human eye so is not as accurate. It can get you pretty close though. CF will cost around £1300+ and SMART is about £200, so SMART might be the best option for cost/performance. You probably won't get an accurate D65 with it unless the SMART III people have a specific spreadsheet for your projector. I think they have a generic DLP spreadsheet but I had trouble getting good results. To be honest, I think it was driver error and impatience to be honest.

    If you have a good eye for grey and know what grey should look like, then you might be able to do it by eye using greyscales like those in Avia or DVE but it becomes very hard to accurately determine the colour of white at 100ire - it can be green/blue with a colour temp of 8000k but you'd be hard pushed to notice it. At least that's the trouble I had whilst the likes of RTFM and Alan Roser of Sim2 seem to have colourimeters instead of eyes. :)

    There is some talk over on avs about using various devices for under $1000 so that might be worth a look:

    http://www.avsforum.com/avs-vb/showthread.php?t=555779

    Gary.
     
  3. Gary Lightfoot

    Gary Lightfoot
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    Do you have a test disk? if so, find the test pattern with a greyscale on it. It should be grey in various intesnsities from black to white (11 bars). If there is any colour tint then you need to adjust the individual RGBs. Yopu should have red green and blue contrast and brightness settings - the brightness ones do the RGB black levels (under 50ire) and the RGB contrasts do the white settings (above 50ire).

    Avia title 1 chapter 7 is on of them IIRC. I can't remember what it is on DVE but I use the Peter Finzel test disk for its easier navigation.

    Gary.
     
  4. Cinematic

    Cinematic
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    Gary, I was wondering if Peter Finzel disc is in any way better than DVE PAL? Does it include any manual in english or just pure german language?

    thanks
     
  5. Gary Lightfoot

    Gary Lightfoot
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    Hi Cinematic,

    I much prefer it myself as it has all the necessary calibrations for setting up a PAL display and is much easier to navigate - despite being in German. There is an English PDF file for it which I can send you if you want to have a look at it and decide before you buy.

    Gary.
     
  6. cyberheater

    cyberheater
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    I've never used a DVD that was worse to navigate then DVE.

    It's horrendous.
     
  7. Cinematic

    Cinematic
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    Thank you Gary, I was thinking about PF disc but German language stopped me. Please send me PDF file - agATkn.pl . I was also considering HQV Benchmark DVD disc to test deinterlacers but I since it's NTSC may be pointless to test PAL systems. Does anybody have it by any chance?

    thanks
     
  8. Sigismund

    Sigismund
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    Hi there - I recently received the HQV Benchmark DVD, which as you've said is in NTSC. For what it is I think it is overpriced, but useful for me as I'm just starting to get into all this calibration stuff!
     
  9. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The only thing on HQV that's useful for calibration are the noisey images designed to show what Noise Reduction techniques do. I use them for showing clients why they shouldn't turn on the NR on their displays......There are no real calibration patterns on there. It's really just a tool that HQV designed to give out to reviewers so they could see where everything fails...unless it's an HQV powered product.....clever eh.

    Gordon
     
  10. Gary Lightfoot

    Gary Lightfoot
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    Hi Gordon,

    I've something similar said about teh Faroudja test disk - I've not seen it so can't comment but have you seen it and would you say it was biased towards their deinterlacers (i.e, it makes others look bad)?

    Gary
     
  11. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    No I've not seen that one Garry. The HQV one is interesting but some of the test seem to show some devices failng miserably when they actually look extremely good on real video material.......Have you seen the HQV disc? I might have a spare I can get hold of and send you to play with. I gave one to Nic Rhodes a few months ago.

    Gordon
     
  12. Gary Lightfoot

    Gary Lightfoot
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    Hi Gordon,

    I'd be greatful for a copy of the disk if it's not too much trouble. You planning on coming down this way any time soon (Elliots)? If not, I'll PM you my address.

    Thanks

    Gary.
     
  13. cyberheater

    cyberheater
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    Can I get a loan of your lightmeter Gary.

    I'll pay for shipping.

    I can't seem to find one on ebay at a reasonable spec for a reasonable price.
     
  14. Gary Lightfoot

    Gary Lightfoot
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    You have a PM

    Gary.
     
  15. cyberheater

    cyberheater
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    Thanks Gary. :thumbsup:
     

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