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Author Topic: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration  (Read 14793 times)

MiguelAngel

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ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« on: December 07, 2010, 07:24:48 am »

 Hello everybody. I'm trying to calibrate my actual desktop monitor (HP F1904, 19", 1280x1024, DVI, TN Pannel, 6 years old, not DDC) in a dimly lit room, only iluminated by a flexo lamp with a blue light (60w) bounced against the wall, behind the monitor. I'm using ColorEyes Display Pro and Spyder2express sensor. I have some doubts:

1. Native White Point: i set Native White point (Luminance 100cd) because my monitor has aged, but will give me more consistent results D65?
2. Gamma target: great doubt L* vs Gamma 2.2. I don't know which is better? I'm wondering if Gamma 2.2 is more standard and better for web purposing
3. Black point target: min. luminance (no problem here)
4. Monitor pre-calibration: i don't understand it. I don't know if i have to use this pre-calibration if i set "Native White point".  My monitor has a OSD menu, where you can modify bright, contrast, color (by default is selected 5700K, but you can select too 6500k, 9300k or custom color, with a sliders for RGB). By default my monitor is too bright for my taste, so i download a bit bright value from 85 to 70 (contrast is set to 75). When i tried monitor pre-calibration, Coloreyes Display show me a crazy values from my RGB channels, especially Blue (-50!)...
5. Finally, i don't know how interpretate Validation Results, but i obtain an Average dE=0.50 and Maximum dE=0.90...

 Thanks for your help

 Kind regards
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Mark D Segal

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #1 on: December 07, 2010, 08:02:13 am »

Hello everybody. I'm trying to calibrate my actual desktop monitor (HP F1904, 19", 1280x1024, DVI, TN Pannel, 6 years old, not DDC) in a dimly lit room, only iluminated by a flexo lamp with a blue light (60w) bounced against the wall, behind the monitor. I'm using ColorEyes Display Pro and Spyder2express sensor. I have some doubts:

1. Native White Point: i set Native White point (Luminance 100cd) because my monitor has aged, but will give me more consistent results D65?
2. Gamma target: great doubt L* vs Gamma 2.2. I don't know which is better? I'm wondering if Gamma 2.2 is more standard and better for web purposing
3. Black point target: min. luminance (no problem here)
4. Monitor pre-calibration: i don't understand it. I don't know if i have to use this pre-calibration if i set "Native White point".  My monitor has a OSD menu, where you can modify bright, contrast, color (by default is selected 5700K, but you can select too 6500k, 9300k or custom color, with a sliders for RGB). By default my monitor is too bright for my taste, so i download a bit bright value from 85 to 70 (contrast is set to 75). When i tried monitor pre-calibration, Coloreyes Display show me a crazy values from my RGB channels, especially Blue (-50!)...
5. Finally, i don't know how interpretate Validation Results, but i obtain an Average dE=0.50 and Maximum dE=0.90...

 Thanks for your help

 Kind regards

I recommend that if you have not done so already you read Andrew Rodney's recent article on this website. It covers much of what you raise here.

I think your background illumination scheme is not the best. I recommend using dim neutral lighting and not bounced off a wall facing you.

Secondly, White Point and Luminance are two different things. White Point establishes the "shade of white" your monitor displays for whites, while Luminance is for brightness. For web images, D65 is probably OK. If you are making prints and viewing them say under halogen bulbs or even Solux bulbs, D65 is likely too cool and you would want something in the range of D50, or a bit cooler - say 5500K. The appropriate value of Luminance depends on what value produces the closest match between screen and print, especially in shadow detail. For web viewing, higher values are likely to better replicate how most people see images on the internet, whereas for prints usually lower values work better, but specific values depend on specific viewing environments. You should experiment with a range from say 90 to 140. Sounds broad, but depending on your main purpose, the correct value will likely be found somewhere therein.

The validation procedure in ColorEyes Display doesn't tell you whether the profile is accurate, but it is useful to tell you whether the profile is performing with internal consistency - i.e. the process of making it didn't get screwed-up. The validation results reflect the differences between the color values in the reference file versus the colour values read from your colorimeter for the 15 patches it reads to do the validation. Any result below 1.0 is good, so the result you reported is good. But only as far as it goes. If there is something wrong with the measuring device and the display and the same hardware has been used to both create and validate the profile, there will be consistent inaccuracy, if you see what I mean.

Turning to the hardware, Spyder 2 is not reputed to be the greatest of colorimeters, and a six year old consumer-grade display may be starting to fray, but this is just a pointer to be ware of - I'd have no way of knowing the condition of your display, or how good it would be at rendering images at lower luminance values; many displays have problems with this. Something to be aware of.

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Mark D Segal (formerly MarkDS)
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NikoJorj

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #2 on: December 07, 2010, 09:12:22 am »

1. Native White Point: i set Native White point (Luminance 100cd) because my monitor has aged, but will give me more consistent results D65?
See http://www.luminous-landscape.com/tutorials/why_are_my_prints_too_dark.shtml
For luminance, 100cd seems not that far from the ballpark with a rather dim ambient lighting. See above.
For white point, season to taste, but "native" may give you better (or less worse) gradients with such a screen).

Quote
2. Gamma target: great doubt L* vs Gamma 2.2. I don't know which is better? I'm wondering if Gamma 2.2 is more standard and better for web purposing
2.2 (or the one of sRGB that is very close) is indeed the web standard, so to speak.

Quote
4. Monitor pre-calibration: i don't understand it.

It's there so that you tune your screen to an optimal state before calibrating, so just do what the thing tells you to.

Quote
5. Finally, i don't know how interpretate Validation Results, but i obtain an Average dE=0.50 and Maximum dE=0.90...
As said, that is a rather good (but very incomplete) figure, that tells you that things didn't go that wrong.
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Nicolas from Grenoble
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MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #3 on: December 07, 2010, 09:24:57 am »

 Thanks for the links. I'll have a look and try to understand something (maybe it's a little complex for me)...

Regards
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MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #4 on: December 07, 2010, 09:33:21 am »

Quote
I recommend using dim neutral lighting

 What kind of lighting do you recommend me?
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Mark D Segal

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #5 on: December 07, 2010, 09:51:46 am »

What kind of lighting do you recommend me?

"neutral" lighting would be the light provided by Solux bulbs, whuich have a colour temperature of about 4700K. A couple of them some distance from your display and not pointed at your work area or right across from it should be workable.
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digitaldog

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #6 on: December 07, 2010, 09:52:13 am »

Start with Native White Point (and Native Gamma), adjust luminance to get a visual match. Only if you find Native WP produces a mismatch should you then go tweaking a value until again, you get a visual match.
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ChasP505

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #7 on: December 07, 2010, 11:51:33 am »

In addition to any help received here, I strongly recommend you ask your CEDP specific questions right at the CEDP help forum:

http://www.integrated-color.com/phpBB3/viewforum.php?f=3

Frankly, I don't know why you would need anything more than the Spyder2 software to calibrate this monitor, but...

In CEDP, use 2.2, and Native.  When choosing native, you don't use the white calibration at all.  You only adjust your monitor's Brightness level to get withing the desired Luminance range.  Also, for black point, select Relative/Minimal.  With these settings, you will be all set to go.

Regarding the validation....  it's only useful if done immediately after creating a profile.  And after profiling, the Current Profile report will tell your your luminance, black level, gamma, and color temperature.
« Last Edit: December 07, 2010, 11:55:09 am by ChasP505 »
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MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #8 on: December 07, 2010, 12:26:51 pm »

Quote
Frankly, I don't know why you would need anything more than the Spyder2 software to calibrate this monitor, but...

Well, i friend tell me that CEDP is a better software for calibration.

Quote
In CEDP, use 2.2, and Native.  When choosing native, you don't use the white calibration at all.  You only adjust your monitor's Brightness level to get withing the desired Luminance range.  Also, for black point, select Relative/Minimal.  With these settings, you will be all set to go.

Thank you very much. I'll try those settings
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MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #9 on: December 07, 2010, 12:29:38 pm »

Quote
"neutral" lighting would be the light provided by Solux bulbs,

Thanks. I'll search in Google where i can buy those bulbs...

Kind regards
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ChasP505

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #10 on: December 07, 2010, 07:36:04 pm »

Well, i friend tell me that CEDP is a better software for calibration.

It is a quality calibration software, but there are complete packages like the X-Rite EyeOne Display2 for less money.  The software is only as accurate as the sensor you use with it.
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Chas P.

MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #11 on: December 08, 2010, 04:22:58 am »

Quote
When choosing native, you don't use the white calibration at all.  You only adjust your monitor's Brightness level to get withing the desired Luminance range

I have a question here. When i adjust my monitor's brightness level (from 85 value by default to 58) to get 100cd/m2 luminance, contrast remains too high (75 by default), so i suppose i have to adust my contrast too. I've seen that when i down the contrast, luminance down too, so i suppose that i have to combine these two factors (bright and contrast) for getting the desired luminance....
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shewhorn

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #12 on: December 08, 2010, 09:19:25 am »

I have a question here. When i adjust my monitor's brightness level (from 85 value by default to 58) to get 100cd/m2 luminance, contrast remains too high (75 by default), so i suppose i have to adust my contrast too. I've seen that when i down the contrast, luminance down too, so i suppose that i have to combine these two factors (bright and contrast) for getting the desired luminance....

It depends upon whether or not you're using a CRT or a TFT monitor. With CRTs contrast actually adjusts luminance and brightness actually adjusts black point (which controls contrast). Why? I have no clue. On a TFT brightness actually does what it says it should (it adjusts luminance) however if you have a contrast control on a TFT I wouldn't touch it. Unlike a CRT where changing contrast, brightness and RGB levels make an adjustment to an analog signal (thus performing a genuine hardware based calibration), the only analog control on a TFT is brightness. All of the other controls are twidling bits and unless you have a monitor with a high resolution monitor LUT, that's not something you want to be doing on the front panel (even if you DO have a monitor with a high res LUT you're best off using the software that is paired with that screen such as Spectraview). If you want to reduce your contrast in Color Eyes Display Pro you can either increase the black level or change it from black level to contrast and select your desired contrast (which will still end up increasing the black level).

Cheers, Joe
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ChasP505

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #13 on: December 08, 2010, 11:34:58 am »

I have a question here. When i adjust my monitor's brightness level (from 85 value by default to 58) to get 100cd/m2 luminance, contrast remains too high (75 by default), so i suppose i have to adust my contrast too. I've seen that when i down the contrast, luminance down too, so i suppose that i have to combine these two factors (bright and contrast) for getting the desired luminance....

Why is the default contrast level "too high"?  Did you notice that for LCD monitors like yours, CEDP doesn't even offer a contrast level setting?  They want you to leave the contrast at the factory default value.  

If you are referring to the "contrast ratio", that's a different issue.  That would be the difference between the luminance level and the black point.  An example would be a luminance of 120cd/m2 and a black value of 0.30cd/m2, yielding a contrast ratio of 400:1.  I earlier recommended using Relative/Minimal for your black setting, but optionally, you can specify an absolute black level or an absolute contrast ratio.

Remember that the contrast ratio of a print is typically less than 300cd/m2, so a very large contrast ratio is no advantage if you do a lot of printing.
« Last Edit: December 08, 2010, 11:38:27 am by ChasP505 »
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MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #14 on: December 08, 2010, 01:47:51 pm »

Quote
Why is the default contrast level "too high"?

Well, i've found contrast level in my monitor too high when i down brightness value and i have a look in this page:

http://www.lagom.nl/lcd-test/white.php

i can distinguish only until the 246 light grey checkerboard pattern, so i suppose that my contrast is too high...   
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ChasP505

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #15 on: December 08, 2010, 04:06:00 pm »

Well, i've found contrast level in my monitor too high when i down brightness value and i have a look in this page:

http://www.lagom.nl/lcd-test/white.php

i can distinguish only until the 246 light grey checkerboard pattern, so i suppose that my contrast is too high...   

That's all well and good if you were just trying to "eyeball calibrate" the monitor, but you've got very powerful software and you're not letting it do it's job.  Also, you should not change any monitor settings after you calibrate, as that will nullify the profile.
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Chas P.

MiguelAngel

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #16 on: December 09, 2010, 05:10:07 am »

Quote
That's all well and good if you were just trying to "eyeball calibrate" the monitor, but you've got very powerful software and you're not letting it do it's job.  Also, you should not change any monitor settings after you calibrate, as that will nullify the profile.

OK, thanks again for your help. Now, i'll print some sample pics for testing accuracy of my calibration.

Best regards

Miguel Angel
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ChasP505

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Re: ColorEyes Display Pro L* vs Gamma 2.2 and pre-calibration
« Reply #17 on: December 09, 2010, 04:04:57 pm »

I also view this image in Photoshop after recalibrating.  View it at 100%.

http://www.aardenburg-imaging.com/news.49.html
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