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Author Topic: some grays not neutral after calibration  (Read 6640 times)

jimh

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some grays not neutral after calibration
« on: December 11, 2016, 11:08:57 am »

I just calibrated my wide gamut display with a Spyder5. In general, things look good.  The Spyder5 software lets me switch calibration on and off, and test images look better, brighter and truer with calibration on.  But a grayscale pattern shows some apparent tint at certain gray levels; some levels look neutral, others very slightly green or magenta.   If I switch off calibration, grays look truer, if somewhat darker.

I feel like things could be better.   Is this effect a limitation of the Spyder5, or of my display, or is something going wrong with the calibration process? 

scyth

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Re: some grays not neutral after calibration
« Reply #1 on: December 11, 2016, 11:22:38 am »

I just calibrated my wide gamut display with a Spyder5. In general, things look good.  The Spyder5 software lets me switch calibration on and off, and test images look better, brighter and truer with calibration on.  But a grayscale pattern shows some apparent tint at certain gray levels; some levels look neutral, others very slightly green or magenta.   If I switch off calibration, grays look truer, if somewhat darker.

I feel like things could be better.   Is this effect a limitation of the Spyder5, or of my display, or is something going wrong with the calibration process?

you might want to add the exact model of your wg display to the post...
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howardm

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Re: some grays not neutral after calibration
« Reply #2 on: December 11, 2016, 12:10:41 pm »

You're not going to find a lot of 'love' here for Spyder products.  That said, you may want to try using different software such as displayCAL and see if that changes/improves things and eliminate that variable.  Got any photo buddies that you can borrow a i1Display or Colormunki from?

jimh

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Re: some grays not neutral after calibration
« Reply #3 on: December 11, 2016, 12:25:03 pm »

The display is a Dell XPS 27  all-in-one.   Yes, I've seen some disparaging of Datacolor, and some mixed reviews.   Although I do strive for good color, and I regularly sell prints, I'm not a portrait or a wedding photographer, and reasonable accuracy is all I really need.   

I'm wondering if, depending on the display, there's some  compromise when trying to profile the entire gamut, and maybe that shows up in the grays.   And if so, I'd rather favor neutral grays at the expense of gamut.  If alternative software like DisplayCal gives better results or has more flexibility, I'll try it.
« Last Edit: December 11, 2016, 12:51:40 pm by jimh »
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Pictus

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Re: some grays not neutral after calibration
« Reply #4 on: December 11, 2016, 04:28:57 pm »

 Argyll+dispcalGUI is much better, but make sure to set the Spyder5 mode to White LED.
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jimh

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Re: some grays not neutral after calibration
« Reply #5 on: December 11, 2016, 06:18:06 pm »

Please pardon my lack of patience with 'open source' software - I've been burned too many times in the past. 

Is DisplayCal something that has a unified installer (.exe or .msi) or is it one of those things where you have to install the latest version of Python, then find some other library, then edit a configuration file, then register on a forum and plead for someone to tell you why it won't run....?

Update:  I installed DisplayCal - or at least I think I did, it doesn't even detect the Spyder5 so it won't do anything.  So much for that option, I guess.
« Last Edit: December 11, 2016, 06:32:22 pm by jimh »
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BobShaw

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Re: some grays not neutral after calibration
« Reply #6 on: December 11, 2016, 11:07:31 pm »

What are the RGB values of the specific grey being sent to the monitor by the computer? If they are not the same then it is not neutral.
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howardm

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Re: some grays not neutral after calibration
« Reply #7 on: December 12, 2016, 12:17:16 am »

Please pardon my lack of patience with 'open source' software - I've been burned too many times in the past. 

Is DisplayCal something that has a unified installer (.exe or .msi) or is it one of those things where you have to install the latest version of Python, then find some other library, then edit a configuration file, then register on a forum and plead for someone to tell you why it won't run....?

Update:  I installed DisplayCal - or at least I think I did, it doesn't even detect the Spyder5 so it won't do anything.  So much for that option, I guess.

It's possible that the Spyder software has some 'daemon' or system piece of software that has an exclusive 'lock' on the device (a very common) and you have to disable that.

Pictus

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Re: some grays not neutral after calibration
« Reply #8 on: December 12, 2016, 07:33:19 am »

Please pardon my lack of patience with 'open source' software - I've been burned too many times in the past. 

Is DisplayCal something that has a unified installer (.exe or .msi) or is it one of those things where you have to install the latest version of Python, then find some other library, then edit a configuration file, then register on a forum and plead for someone to tell you why it won't run....?

This type of info is in the link I posted or this http://www.modelmayhem.com/forums/post/870355/1#post17806610
 
Quote


Update:  I installed DisplayCal - or at least I think I did, it doesn't even detect the Spyder5 so it won't do anything.  So much for that option, I guess.

See https://hub.displaycal.net/forums/topic/spyder5-not-detected/

BTW, what is the monitor model you have?
You can get better  results by using the monitor Custom mode and change the RGB channels to achieve the desired White Point.
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scyth

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Re: some grays not neutral after calibration
« Reply #9 on: December 12, 2016, 10:00:49 am »

Please pardon my lack of patience with 'open source' software - I've been burned too many times in the past. 

the same can be said about the commercial one...
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jimh

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Re: some grays not neutral after calibration
« Reply #10 on: December 12, 2016, 11:52:04 am »

The display on this all-in-one has no color adjustments.  Gamma, brightness and contrast can be adjusted via the Intel HD Graphics application.   

After a few attempts at different brightness targets, I got a better result; grays are still slightly off but closer to neutral.  I sent a ticket to Datacolor about this, and got a reply telling me to follow the directions.  :-0       But they also said I could upgrade to 'Elite' and then get some gray-balancing capability.  I think I'll do that.

scyth

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Re: some grays not neutral after calibration
« Reply #11 on: December 12, 2016, 12:08:14 pm »

The display on this all-in-one has no color adjustments.  Gamma, brightness and contrast can be adjusted via the Intel HD Graphics application.   

After a few attempts at different brightness targets, I got a better result; grays are still slightly off but closer to neutral.  I sent a ticket to Datacolor about this, and got a reply telling me to follow the directions.  :-0       But they also said I could upgrade to 'Elite' and then get some gray-balancing capability.  I think I'll do that.

you seriously will be better of with dumping Datacolor, buying i1Display Pro, removing Intel software that can alter the settings (some igfx* stuff), using DisplayCAL/Argyll and setting parameters through display menu...
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jimh

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Re: some grays not neutral after calibration
« Reply #12 on: December 12, 2016, 03:04:53 pm »

Hmmm just found out that the upgrade to Elite, to get that "better" gray balance, costs $99.   Ow.  Ow ow ow.

howardm

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Re: some grays not neutral after calibration
« Reply #13 on: December 12, 2016, 03:30:34 pm »

I saw a day or 3 ago via B&H they had the i1Display Pro on sale for around $150ish.

Frankly, I wouldn't dump another $99 into a Spyder.

jimh

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Re: some grays not neutral after calibration
« Reply #14 on: December 12, 2016, 09:11:32 pm »

No, I'm not paying $99 just to get one additional software feature that isn't even guaranteed to solve the problem.   I'll accept what I have for now, and maybe look into other software.   

BobShaw

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Re: some grays not neutral after calibration
« Reply #15 on: December 12, 2016, 10:09:05 pm »

As far as I know a Spyder is a Spyder and the difference in price is the software. You can use it with other software. I use Spyder4 with ColorNavigator.
So I doubt that there is anything wrong with the Spyder. You should revisit the process and actually read the RGB values before and after. Easy on a Mac, no idea on a PC.
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scyth

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Re: some grays not neutral after calibration
« Reply #16 on: December 13, 2016, 09:50:05 am »

Hmmm just found out that the upgrade to Elite, to get that "better" gray balance, costs $99.   Ow.  Ow ow ow.

you can't seriously buy anything from the company that invented "spectrocolorimeter"
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jimh

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Re: some grays not neutral after calibration
« Reply #17 on: December 13, 2016, 10:43:33 am »

After several attempts, I did end up with an acceptable calibration.   If I look at a grayscale test image I still see some very slight tint in some bands, depending on the pattern; some test patterns don't show this.   When editing an actual b&w image, it looks satisfactorily neutral.   

howardm

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Re: some grays not neutral after calibration
« Reply #18 on: December 13, 2016, 12:24:07 pm »

I'd assume it's some sub-pixel aliasing going on there. 

jimh

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Re: some grays not neutral after calibration
« Reply #19 on: December 13, 2016, 07:11:56 pm »

I thought Datacolor's response was basically:  'if you're not satisfied with how well it works, for $99 we might be able to make it work a little better'.

I'm actually a former software engineer (retired) and I think I get the basics of profiling.   At bottom, a calibration is a table of values, translating a standard color space to what the display requires.  I might expect that someone has a tool for hand-tweaking this table, using something like a Spyder.  You put a large grayscale pattern on the screen; put the Spyder over a bar, and the program lets you tweak that color, with a green/magenta slider,  until it looks neutral.  Repeat on each bar in the test pattern.   Then the software would  interpolate all the intervening shades to get a smooth gradient.  Of course to avoid noticeable discontinuities in gradients approaching neutral gray, the whole table has to be 'shifted' around the neutral points.  I don't know how to do this myself, because I don't understand the math behind color profiles; but someone who does, could do this.

Is there something like this already?
« Last Edit: December 13, 2016, 10:04:53 pm by jimh »
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