I managed to pull my old CG-21 of the moth balls, to serve as a second display - how could have I ever lived without this convenience? Crazy. Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish". Any suggestions? / Roger
Expecting the same calibration targets to produce a visual match between dissimilar display systems is one problem. Solution? You’ll need to alter the calibration targets for one to match the other through trail and error and don’t expect an exact match. Especially if their native color gamuts differ greatly and they use differing backlight technologies. You want two displays to exactly match? Get two NEC (or similar) of the same make and model, calibrate them with their host software products using the same instrument, they should match (the entire idea behind color reference display systems. Andrew Rodney www.digitaldog.net
On Feb 5, 2020, at 10:20 AM, Roger Breton via colorsync-users <colorsync-users@lists.apple.com> wrote:
I managed to pull my old CG-21 of the moth balls, to serve as a second display - how could have I ever lived without this convenience? Crazy.
Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish".
Any suggestions?
Charles J. Hirsch of RCA, in November 1964, published a paper in the IEEE Transactions on Broadcast and Television Receivers, "A study of the need for color controls on color TV receivers in a color TV system operating perfectly." In this paper he analyzed the effects of differences in spectral response among individual observers with normal color discrimination, as recorded by Gibson and Tyndall in 1923-24. Hirsch's conclusion was that with NTSC primaries (similar to Adobe RGB), adjustments of +/- 20% or more in the proportions of a mixture might be required to nullify the extremes of observer differences. In other words, do not expect that you are a match to the standard observer, and expect to see some difference between displays that have different spectra. I, too, have two disparate monitors, and they do not match exactly to my eye when the i1pro says they should. I use the larger, wider gamut one for judging images and the smaller one for menus. I also note that the mismatch when first turned on is much greater than after 30 minutes of warmup. I suspect this is due to change in the color of the fluorescent backlight as the internal pressure stabilizes. -----Original Message----- From: colorsync-users <colorsync-users-bounces+waynebretl=cox.net@lists.apple.com> On Behalf Of Roger Breton via colorsync-users Sent: Wednesday, February 05, 2020 10:21 AM To: colorsync-users@lists.apple.com Subject: Two monitors, side by side I managed to pull my old CG-21 of the moth balls, to serve as a second display - how could have I ever lived without this convenience? Crazy. Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish". Any suggestions? / Roger _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net This email sent to waynebretl@cox.net
Roger Breton via colorsync-users wrote:
Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish".
Your CMF's are not the same as the standard observer. The most practical fix is to tweak the white point on one to visually match the other. [ You may find after doing this that they then match at one distance, but not from a different distance. CMF's depend on viewing angle. ]
Question: so, colorimeter see the monitors as "identical" because their respective spectra produce the same "signal" to the brain, in terms of "sensation". I don't suppose spectral measurements of their respective white points could not be used in some sort of advanced spectral matching computation?
If you happen to know your own CMF's, then yes, you should be able to get them to match via measurement. Cheers, Graeme Gill.
Hi Roger, Just measure the spectral response of these two monitors that you have set to be at the same chromaticity and luminance, you will see that the Blue, Green and Red band-pass filters used in their panels are very different in terms of width and position on the wavelength axis. In a study I made few years back, I have tested two physically identical desktop viewers equipped with fresh 60 cm T8 tubes from two different manufacturers and two displays. And have tried to get the two displays to match each other as well as an unprinted FOGRA39-certifed proofing stock placed in the desktop viewers. To get them visually close to each other and to the real samples, I had to set them to different white points. I have to point out that the fresh T8 tubes from the two manufacturers that were advertised to be ISO 3664:2009 compliant, gave visibly/considerably different results. Getting things aligned has not been easy or complete. And things got even harder when I called in other people to find their best match. When I tried to test the visual match with a total of 6 people, they all disagreed. I have then let each of them to find their best match by calibrating/profiling each monitor to a different white point; all came up with different results. But there was a marked difference between the two monitors. While people set Monitor A to quite different white points to achieve their best match, the white point picked for Monitor B have been very close to each other. While Monitor A had a pinkish cast at all of the white point settings, Monitor B had a neutral white appearance. Below are the spectral power distribution curves for the two monitors. Their white points were both set to 5400ºK during calibration/profiling process. Monitor A https://www.dropbox.com/s/51p73dmypuuetcu/Monitor%20A%205400K.png?dl=0 Monitor B https://www.dropbox.com/s/2ng8bmp576k3xg7/Monitor%20B%205400K.png?dl=0 When you have narrow-non-overlapping RGB filters (and when the Red filters is closer to the right end of the visible spectrum) the disagreement between the observers grow. Monitor B, with its wide-overlapping filters, is behaving like a light box on which you can view transparencies. As I have made the measurements in “Ambient” mode in a dark room from a distance of about 30 cm, you will also see the CRI values, (as well as the slightly shifted CCTs): Monitor A - CRI: 37 Monitor B - CRI: 93 I have made similar measurements on displays from different manufacturers. They all have quite different SPD curves. The narrower the band pass filters, the greater becomes the disagreement between the observers. If the Red filter peaks at somewhere around 650 nm, what most people observe is a pinkish cast in the white point and light grays. Most monitor profiling software packages also have a built-in verify module. Most of those which can do CMYK simulation, do it “relative to display profile white point” and the verifier says OK, even if you calibrate/profile your monitor to a range of CCTs, say between 5200 to 5800ºK. Florian Hoech’s DisplayCAL 3 lets you to switch this off. You can then see where your monitor is actually sitting. https://www.dropbox.com/s/kbaeij6z1w73578/DisplayCAL%203%20Verify.png?dl=0 Apparently, in the world of soft-proofing/monitor proofing everything seems to be “relative”. Best regards, Refik Telhan Light and Color Management Consultancy -------------------------------- On 05.02.2020 20:21, "colorsync-users on behalf of Roger Breton via colorsync-users" <colorsync-users-bounces+rtelhan=icloud.com@lists.apple.com on behalf of colorsync-users@lists.apple.com> wrote: I managed to pull my old CG-21 of the moth balls, to serve as a second display - how could have I ever lived without this convenience? Crazy. Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish". Any suggestions? / Roger _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/rtelhan%40icloud.com This email sent to rtelhan@icloud.com
A long time ago I had a Samsung T something and a CG210 - the latter which I still own. I used Basicolor Display to measure the CT of one and used that as a basis for the calibration of the other. I know it shouldn't have worked, but it worked quite well, both monitors were perfectly usable for photo retouch. . I displayed Colorcheckers on both when doing the setup, and had a young lady help me and we agreed we had quite a good match. I still occasionally use the CG210 and don't consider it obsolete. Edmund On Sat, Feb 8, 2020 at 6:35 AM Refik Telhan via colorsync-users < colorsync-users@lists.apple.com> wrote:
Hi Roger,
Just measure the spectral response of these two monitors that you have set to be at the same chromaticity and luminance, you will see that the Blue, Green and Red band-pass filters used in their panels are very different in terms of width and position on the wavelength axis.
In a study I made few years back, I have tested two physically identical desktop viewers equipped with fresh 60 cm T8 tubes from two different manufacturers and two displays. And have tried to get the two displays to match each other as well as an unprinted FOGRA39-certifed proofing stock placed in the desktop viewers. To get them visually close to each other and to the real samples, I had to set them to different white points. I have to point out that the fresh T8 tubes from the two manufacturers that were advertised to be ISO 3664:2009 compliant, gave visibly/considerably different results. Getting things aligned has not been easy or complete. And things got even harder when I called in other people to find their best match.
When I tried to test the visual match with a total of 6 people, they all disagreed. I have then let each of them to find their best match by calibrating/profiling each monitor to a different white point; all came up with different results. But there was a marked difference between the two monitors. While people set Monitor A to quite different white points to achieve their best match, the white point picked for Monitor B have been very close to each other. While Monitor A had a pinkish cast at all of the white point settings, Monitor B had a neutral white appearance.
Below are the spectral power distribution curves for the two monitors. Their white points were both set to 5400ºK during calibration/profiling process.
Monitor A
https://www.dropbox.com/s/51p73dmypuuetcu/Monitor%20A%205400K.png?dl=0
Monitor B
https://www.dropbox.com/s/2ng8bmp576k3xg7/Monitor%20B%205400K.png?dl=0
When you have narrow-non-overlapping RGB filters (and when the Red filters is closer to the right end of the visible spectrum) the disagreement between the observers grow. Monitor B, with its wide-overlapping filters, is behaving like a light box on which you can view transparencies.
As I have made the measurements in “Ambient” mode in a dark room from a distance of about 30 cm, you will also see the CRI values, (as well as the slightly shifted CCTs):
Monitor A - CRI: 37
Monitor B - CRI: 93
I have made similar measurements on displays from different manufacturers. They all have quite different SPD curves. The narrower the band pass filters, the greater becomes the disagreement between the observers. If the Red filter peaks at somewhere around 650 nm, what most people observe is a pinkish cast in the white point and light grays.
Most monitor profiling software packages also have a built-in verify module. Most of those which can do CMYK simulation, do it “relative to display profile white point” and the verifier says OK, even if you calibrate/profile your monitor to a range of CCTs, say between 5200 to 5800ºK. Florian Hoech’s DisplayCAL 3 lets you to switch this off. You can then see where your monitor is actually sitting.
https://www.dropbox.com/s/kbaeij6z1w73578/DisplayCAL%203%20Verify.png?dl=0
Apparently, in the world of soft-proofing/monitor proofing everything seems to be “relative”.
Best regards,
Refik Telhan
Light and Color Management Consultancy
--------------------------------
On 05.02.2020 20:21, "colorsync-users on behalf of Roger Breton via colorsync-users" <colorsync-users-bounces+rtelhan= icloud.com@lists.apple.com on behalf of colorsync-users@lists.apple.com> wrote:
I managed to pull my old CG-21 of the moth balls, to serve as a second
display - how could have I ever lived without this convenience? Crazy.
Of course, first thing I did was to try to make it "look" like my NEC
PA271W. They're both LCD monitors yet, at the same chromaticity and
Luminance, they don't look the "same". One is "reddish" (CG-21) while the
other (NEC) is "greenish".
Any suggestions?
/ Roger
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Hi Edmund, EIZO’s CG210 is a robust, stable and uniform monitor with an sRGB gamut. I still see them in action after about 20 000 or even 25 000 hours of use albeit at reduced luminance levels, such as 75-80 nits. They are still useful tools. The gamut of your Samsung T something monitor was most probably also sRGB with a similar spectral output. This may explain why your setup worked. With all the different display technologies -QLED, OLED, mini-LED and micro-LED to name a few- that are competing today, getting things aligned is becoming harder. You can see how different they can be on Roger N. Clark’s web site: https://clarkvision.com/articles/color-spaces/ While the Green (peaking at around 450 nm) and Blue (peaking at 530 nm) filters from different devices appear to be closer to each other [and to the response of the S (peaking at 430 nm) and M (peaking at 534 nm) cones], the Red (peaking between 617 - 653 nm) filters vary widely from eacn other [and from the L (peaking at 564 nm) cone]. Getting monitors with different spectral emissions and gamuts aligned to each other and to a desktop viewer with an ever-aging T8 tube can become tiring, to say the least. Best, Refik From: edmund ronald <edmundronald@gmail.com> Date: 8 February 2020 Saturday 14:16 To: "rtelhan@icloud.com" <rtelhan@icloud.com> Cc: "'colorsync-users?lists. apple. com' List" <colorsync-users@lists.apple.com> Subject: Re: Two monitors, side by side A long time ago I had a Samsung T something and a CG210 - the latter which I still own. I used Basicolor Display to measure the CT of one and used that as a basis for the calibration of the other. I know it shouldn't have worked, but it worked quite well, both monitors were perfectly usable for photo retouch. . I displayed Colorcheckers on both when doing the setup, and had a young lady help me and we agreed we had quite a good match. I still occasionally use the CG210 and don't consider it obsolete. Edmund On Sat, Feb 8, 2020 at 6:35 AM Refik Telhan via colorsync-users <colorsync-users@lists.apple.com> wrote: Hi Roger, Just measure the spectral response of these two monitors that you have set to be at the same chromaticity and luminance, you will see that the Blue, Green and Red band-pass filters used in their panels are very different in terms of width and position on the wavelength axis. In a study I made few years back, I have tested two physically identical desktop viewers equipped with fresh 60 cm T8 tubes from two different manufacturers and two displays. And have tried to get the two displays to match each other as well as an unprinted FOGRA39-certifed proofing stock placed in the desktop viewers. To get them visually close to each other and to the real samples, I had to set them to different white points. I have to point out that the fresh T8 tubes from the two manufacturers that were advertised to be ISO 3664:2009 compliant, gave visibly/considerably different results. Getting things aligned has not been easy or complete. And things got even harder when I called in other people to find their best match. When I tried to test the visual match with a total of 6 people, they all disagreed. I have then let each of them to find their best match by calibrating/profiling each monitor to a different white point; all came up with different results. But there was a marked difference between the two monitors. While people set Monitor A to quite different white points to achieve their best match, the white point picked for Monitor B have been very close to each other. While Monitor A had a pinkish cast at all of the white point settings, Monitor B had a neutral white appearance. Below are the spectral power distribution curves for the two monitors. Their white points were both set to 5400ºK during calibration/profiling process. Monitor A https://www.dropbox.com/s/51p73dmypuuetcu/Monitor%20A%205400K.png?dl=0 Monitor B https://www.dropbox.com/s/2ng8bmp576k3xg7/Monitor%20B%205400K.png?dl=0 When you have narrow-non-overlapping RGB filters (and when the Red filters is closer to the right end of the visible spectrum) the disagreement between the observers grow. Monitor B, with its wide-overlapping filters, is behaving like a light box on which you can view transparencies. As I have made the measurements in “Ambient” mode in a dark room from a distance of about 30 cm, you will also see the CRI values, (as well as the slightly shifted CCTs): Monitor A - CRI: 37 Monitor B - CRI: 93 I have made similar measurements on displays from different manufacturers. They all have quite different SPD curves. The narrower the band pass filters, the greater becomes the disagreement between the observers. If the Red filter peaks at somewhere around 650 nm, what most people observe is a pinkish cast in the white point and light grays. Most monitor profiling software packages also have a built-in verify module. Most of those which can do CMYK simulation, do it “relative to display profile white point” and the verifier says OK, even if you calibrate/profile your monitor to a range of CCTs, say between 5200 to 5800ºK. Florian Hoech’s DisplayCAL 3 lets you to switch this off. You can then see where your monitor is actually sitting. https://www.dropbox.com/s/kbaeij6z1w73578/DisplayCAL%203%20Verify.png?dl=0 Apparently, in the world of soft-proofing/monitor proofing everything seems to be “relative”. Best regards, Refik Telhan Light and Color Management Consultancy -------------------------------- On 05.02.2020 20:21, "colorsync-users on behalf of Roger Breton via colorsync-users" <colorsync-users-bounces+rtelhan=icloud.com@lists.apple.com on behalf of colorsync-users@lists.apple.com> wrote: I managed to pull my old CG-21 of the moth balls, to serve as a second display - how could have I ever lived without this convenience? Crazy. Of course, first thing I did was to try to make it "look" like my NEC PA271W. They're both LCD monitors yet, at the same chromaticity and Luminance, they don't look the "same". One is "reddish" (CG-21) while the other (NEC) is "greenish". Any suggestions? / Roger _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/rtelhan%40icloud.com This email sent to rtelhan@icloud.com _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/edmundronald%40gmail... This email sent to edmundronald@gmail.com
participants (6)
-
Andrew Rodney
-
edmund ronald
-
Graeme Gill
-
graxx＠videotron.ca
-
Refik Telhan
-
Wayne Bretl