Calibrating help needed

SystemSystem Registered Users Posts: 8,186 moderator
edited January 3, 2007 in Digital Darkroom
*** excuse my lack or misuse of technical terms as I'm a total n00b at calibration.

Calibrating the Dell 2407wfp w/ eye-one display 2 ~ 6500k / 2.2 gamma / 120 lum

After a few hours of frustration trying to dial this monitor in I finally figured out some of the issues people seem to be having. The biggest complaints the internet seems to offering have to with luminance and variations from one side of the lcd to another. After reaching a near perfect calibration 6500k / 2.2 gamma / 120 luminance (the folowing yellow text seems to be complete rubbish, live and learn) I have no discernible variations from one side to another as measured via the eye dropper tool in PS cs2 on duplicate images. Readings are within 1% <edit> CMYK </edit> for all areas compared.

The issue with luminance seems to center around not being able to drop the brightness low enough to achieve a 120 reading. This monitor is exceptionally bright and from the factory many settings are pegged at 100%. Adjusting the brightness to 0% was not enough to bring the luminance into spec. In fact the lowest luminance I could achieve was 137.6. Since there is no contrast adjustment I though i was out of luck. What I failed to realize is that the RGB adjustments are also pegged at 100%. What this meant was that I was dialing them in during calibration by lowering them from 100% until I reached 6500k.

It tunes out the 6500k is only a ratio of RGB and that by dropping the starting point RGB values (let's say to 70%) and then dialing in the ratio I could still achieve the 6500k temp I wanted and this dropped the brightness so that I was able to achieve luminance readings as low as 60 and the 120 I wanted was easily attainable.

If there are problems with this approach please clue me in.

Comments

  • BendrBendr Registered Users Posts: 665 Major grins
    edited January 1, 2007
    truth wrote:
    After reaching a near perfect calibration 6500k / 2.2 gamma / 120 luminance I have no discernible variations from one side to another as measured via the eye dropper tool in PS cs2 on duplicate images. Readings are within 1% RGB for all areas compared.

    I'm confused, Did you take a photo of the monitor then go off of that?

    Because otherwise, PS has no way to know what your LCD is displaying, only what the computer is sending, Hence the reason for devices such as the Huey(http://dgrin.smugmug.com/gallery/1174347) This allows the computer to see what the monitor is displaying, and then make adjustments so that what the monitor displays, matches what it is sending...

    Good luck!
  • SystemSystem Registered Users Posts: 8,186 moderator
    edited January 1, 2007
    Bendr wrote:
    I'm confused, Did you take a photo of the monitor then go off of that?

    Because otherwise, PS has no way to know what your LCD is displaying, only what the computer is sending, Hence the reason for devices such as the Huey(http://dgrin.smugmug.com/gallery/1174347) This allows the computer to see what the monitor is displaying, and then make adjustments so that what the monitor displays, matches what it is sending...

    Good luck!
    Hmm...I see what you're saying as far as the readings being a measurement of info not display. As such that theory is out the window for measuring side to side. To the eye there is no discernible variation but that could just be my eyes.

    One issue with such a wide monitor is that your vantage point effects the brightness of the image. Meaning that as you move right to left relative to the screen the image shifts. To accurately compare right to left visually you need to be sure you viewing angle for each side by side image is the same.

    As far as the huey goes, I wanted to be able to calibrate multiple monitors and the ambient light is 100% stable in my workspace as there is no natural light. As such the eye-one's one time ambient light measurement is sufficient and the overall calibration controls are far more comprehensive than the Huey's. They are a bit intimidating at first, but with a little trial and error, some google hunting and the advice from a few far more talented friends I think I have it dialed.
  • colourboxcolourbox Registered Users Posts: 2,095 Major grins
    edited January 1, 2007
    truth wrote:
    by dropping the starting point RGB values (let's say to 70%) and then dialing in the ratio I could still achieve the 6500k temp I wanted and this dropped the brightness so that I was able to achieve luminance readings as low as 60 and the 120 I wanted was easily attainable.
    If there are problems with this approach please clue me in.

    What I'm about to say is not authoritative, but from what I have read, LCD monitors really have only one real adjustment: the backlight brightness. When you make an adjustment like contrast or RGB, I think you're making a color lookup table adjustment that's piled on top of the alteration done with the profile. If I understand all of this correctly (and there's a fair chance that I don't), your method *might* put the monitor at more risk of posterization in gradients and shadows. But you know what, it probably comes down to this: If you don't see those kinds of problems and your prints match your monitor, just call it "Done" and enjoy the thing. thumb.gif
  • SystemSystem Registered Users Posts: 8,186 moderator
    edited January 1, 2007
    Who the hell changed my thread title? Seriously what the heck is that about? You can piss off.

    Colourbox, thanks. If I'm understanding you correctly I should try and raise the RGB levels to the maximum that allows me to achieve the luminance value I am looking for. That should minimize the risks you detail no?
  • DavidTODavidTO Registered Users, Retired Mod Posts: 19,160 Major grins
    edited January 1, 2007
    truth wrote:
    Who the hell changed my thread title? Seriously what the heck is that about? You can piss off.


    Truth, let me clue you in on something. This is not your forum. You've been banned before, and you're heading for another. Watch your tongue.
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • AndyAndy Registered Users Posts: 50,016 Major grins
    edited January 1, 2007
    truth wrote:
    Who the hell changed my thread title? Seriously what the heck is that about? You can piss off.
    I changed it because it was scary. Reading is hard, long thread titles suck.

    Are you in need of help? Yes. Thread title says it all then.

    Sorry, deal with it.
  • DoctorItDoctorIt Administrators Posts: 11,951 moderator
    edited January 2, 2007
    He's probably just mad because the model of the monitor was in the original title and he's forgotten it now. As any Dell user knows, it takes an act of congress to figure out exactly what you're working with.

    here you go:

    Calibrating the Dell 2407wfp w/ eye-one display 2 ~ 6500k / 2.2 gamma / 120 lum


    and now I will piss off, cuz I don't know jack about this topic lol3.gif
    Erik
    moderator of: The Flea Market [ guidelines ]


  • SystemSystem Registered Users Posts: 8,186 moderator
    edited January 2, 2007
    DoctorIt wrote:
    He's probably just mad because the model of the monitor was in the original title and he's forgotten it now. As any Dell user knows, it takes an act of congress to figure out exactly what you're working with.

    here you go:

    Calibrating the Dell 2407wfp w/ eye-one display 2 ~ 6500k / 2.2 gamma / 120 lum


    and now I will piss off, cuz I don't know jack about this topic lol3.gif
    Feel the love. I actually wanted in the title for google searches. There's a ton of debate on this subject in other corners of the interweb so I thought I'd at least give it a shot at coming up in a search.
  • ginger_55ginger_55 Registered Users Posts: 8,416 Major grins
    edited January 3, 2007
    Anything with "Calibration" prominent suits me. I have a new monitor coming, and everything I have read re calibration scares me to death.

    Oh, and it is a Dell, Dr It, smile. 19" ultra sharp LCD.

    I like Truth!!!! I mean, with a small "t" and with a large "T".

    Search titles can be useless, thanks for trying to clarify this one. Not that I know exactly what the original was compared to the one now. I did copy parts of the responses and e-mailed them to me to save.

    And I did find it and read it because of the original title in the "new posts" thing.

    Thanks all,

    ginger
    After all is said and done, it is the sweet tea.
  • AndyAndy Registered Users Posts: 50,016 Major grins
    edited January 3, 2007
    truth wrote:
    Feel the love. I actually wanted in the title for google searches. There's a ton of debate on this subject in other corners of the interweb so I thought I'd at least give it a shot at coming up in a search.
    It will be in google searches, trust me.
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