Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: Wayne Fox on May 11, 2011, 10:34:29 pm
-
Finally decided to bite the bullet and move to a wide gamut display. I've been experimenting with calibrating it with varying degrees of success. I finally was able to get a nice display to print match, but only after doing a couple of slight manual tweaks in the Spectraview II software. Without this there was a very subtle green cast, especially in the mid-tone grays.
Just curious if this is OK, or for some reason a not a good idea. (is it typical?) I know quite a few of you are running the NEC displays, so much more experience with them.
Really like it now that I've got it setup.
-
let the display burn-in for a 100 hours before trying to do/calibrate critical work. The CCFL tubes will mellow out a bit.
On my 241, I did end up setting specific x/y coordinates.
-
I agree with the burn in...and I don't dispute the 100 hours (although I didn't wait that long with my PA241W).
Also, there are some important things to check in the SpectraView software & Prefs; you want the option in the Prefs to average low luminance measurements, you want the highest quality (52 steps) in the Calibration and Profile option, you alwso want Best grayscale color tracking and you prolly want the option to do Extended luminance stabilization time, you also prolly want the Factory measurements in the source for color chromaticities. I presume you have selected the target settings for Photo Editing; D65, Gamma 2.2, luminosity 140 and contrast ratio Monitor Default? You may end up wanting to adjust the contrast ratio to lower it depending on what display you are coming from. What hardware are you using as the measurement device?
-
What color sensor was used for calibration? I usually saw green cast after D65 calibration done with regular i1 colorimeter.
As for Prefs - highest quality (52 steps), best grayscale color tracking and extended luminance stabilzation time work you're calibrating the display with a colorimeter, and I'm not sure if they're necessarily such a good idea when a spectrophotometer (i1pro, ColorMunki) is used.
I've also heard that it's good to let the display burn-in for a couple of hours, with the whole screen set to white if possible (it has something to do with liquid crystal).
-
Hi Wayne, I just set up my PA271W and are experiencing the same colour cast as you.
-
Thanks for all the good advice. The device is the included i1 display. (I assume it's just an i1 with NEC printed on it). I haven't really looked into spectravsion II much, just did the basic steps, but the manual tweak has it pretty good (a little better than my 30" apple). Sounds like the best plan is to give the thing some time to burn in, then revisit the calibration and make sure I'm doing it right. After it burns in, I'll check out some things (especially some of the details from Jeff, thx) just to make sure I'm doing it right.
-
On the contrast the default for the monitor is much higher than you can achieve on an inkjet print. You might dial this down to 350:1 for calibration purposes.
-
yes, you'll want to lower the contrast. I think mine is something like .35 black
-
"Your" i1d2 is not just a printed NEC oem version. NEC has actually modified the filter for their specific reason to optimized the result with their monitor. but under the earlier report from Ethan, these sensor will NOT do a good job on other monitors.
-
On the contrast the default for the monitor is much higher than you can achieve on an inkjet print. You might dial this down to 350:1 for calibration purposes.
yes, you'll want to lower the contrast. I think mine is something like .35 black
I wouldn't make a general rule here, the perceived contrast can be substantially lowered by a light flare on the displays diffuser. I've used the basICColor DISCUS to make few measurements from the distance in various ambient light conditions, and in a bright enviroment the contrast ratio was only ~150:1, while the contact measurement was showing >500:1 and more.
-
"Your" i1d2 is not just a printed NEC oem version. NEC has actually modified the filter for their specific reason to optimized the result with their monitor. but under the earlier report from Ethan, these sensor will NOT do a good job on other monitors.
Found that out. Used it to calibrate the apple and it was horrible.
-
let the display burn-in for a 100 hours before trying to do/calibrate critical work. The CCFL tubes will mellow out a bit.
I understand that the CCFL tubes may "mellow" after some number of hours of use, but I don't understand why you can't get a reasonably close calibration before that (and then not be surprised if the monitor drifts from that initial calibration as the tubes "mellow").
I just got a new NEC PA 241W with the Spectraview II software and NEC branded calibration puck. I plugged the monitor in and calibrated it and the screen has a greenish color cast. I spent a couple of hours researching this issue on the web and found this thread (which I had read previously) and made all the suggested tweaks to the software suggested by Jeff Schewe. I did another calibration and the monitor still has a greenish cast.
Previously, I was using an Eizo CG21 calibrated with ColorEyes DisplayPro and a DPT-94 and it looked great compared to the new PA 241W. I uninstalled ColorEyes DisplayPro just to make sure there would be no conflict with the Spectraview II software.
I know I shouldn't expect two different monitors using two different software packages and two different calibration instruments to look the same, but the thing is that whites in my prints printed on my Epson 4900 through Imageprint using IP profiles look white on the print and they looked white on my Eizo, but when I look at the printed image in Photoshop on my new PA 241W, the whites have a greenish tint (after making J. Schewe's suggested tweaks to the Spectraview software and recalibrating). There's no way I can do accurate color correction using this monitor.
BTW, I just checked and the white I'm referring to in my image has RGB values of 240,240,239 in Photoshop, but looks green on my monitor.
It just doesn't seem to me that this problem is going to slowly go away by itself after I let the monitor burn in for 100 hours.
Any help would be appreciated.
-
BTW, I just checked and the white I'm referring to in my image has RGB values of 240,240,239 in Photoshop, but looks green on my monitor.
You have to adjust the white point using x/y custom values. See: http://www.luminous-landscape.com/forum/index.php?topic=55782.new#lastPost:
When people report their display is too green/magenta, the fix can be zooming in on the central white point of the CIE xy diagram in the SpectraView software. It will give you a better idea of how changing the x and y values will affect the white point. If the screen is too green, you‘ll want to move the white point down and to the right (vise versa for magenta). Make tiny adjustments (i.e. 0.002) and recalibrate. Understand that this only works if the calibration software allows you to enter specific CIE xy values.
-
Andrew, I'm stepping in because I'm curious. Is this something that has been commonly observed with the NEC PA series?
-
Andrew, I'm stepping in because I'm curious. Is this something that has been commonly observed with the NEC PA series?
And one other question - is the discrepancy in white point values caused by sample variation in the NEC branded calibration instrument? If not, what is the cause?
-
I just got a new NEC PA 241W with the Spectraview II software and NEC branded calibration puck. I plugged the monitor in and calibrated it and the screen has a greenish color cast.
And one other question - is the discrepancy in white point values caused by sample variation in the NEC branded calibration instrument? If not, what is the cause?
Try to calibrate the display to D65 without a sensor using NEC Multiprofiler software, and tell us if the green cast is still there.
-
And one other question - is the discrepancy in white point values caused by sample variation in the NEC branded calibration instrument? If not, what is the cause?
Possible, but all displays and graphic systems they utilize are different or we wouldn’t have to calibrate them. Point is, you should be able to fix the issue by adjusting the WP with the provided tools.
-
Try to calibrate the display to D65 without a sensor using NEC Multiprofiler software, and tell us if the green cast is still there.
Thanks for the suggestion - I'll try this tonight and post results later.
-
Possible, but all displays and graphic systems they utilize are different or we wouldn’t have to calibrate them. Point is, you should be able to fix the issue by adjusting the WP with the provided tools.
I don't really understand what you're saying. The point of calibration is to get consistency. There are three variables, the monitor, the calibration software and the hardware calibration device.
Now, it's a given that the monitors have some sample variation and the colors will drift over time. That's why we calibrate them. There's no variation in the Spectraview II software so if when I calibrate using the NEC colorimeter my whites have a greenish cast, either I'm using the software incorrectly or the colorimeter is off.
One possibility is to adjust the white point using the x/y custom values until the whites look white - but then I'm really just using my eyeballs as the colorimeter. The other option would be to return the colorimeter until I get one that seems to work without having to change the white point by what looks good to my eye.
So, I'm wondering if the problem that a number of people have is just poor quality control with the NEC branded colorimeter. I never had this problem using ColorEyes Display Pro with my DPT-94.
-
I don't really understand what you're saying. The point of calibration is to get consistency.
If that were true, there would only be one calibration target aim points. We’d always use them for that consistency. But its pretty clear that we have to specifically ask for a target for TRC gamma (not all that important), white point and luminance (very important) and if available, contrast ratio. The point of calibration is first and foremost to set the display conditions to an idealized behavior (for me and many others, to visually match a print next to that display). Then we want consistency in that behavior.
One possibility is to adjust the white point using the x/y custom values until the whites look white - but then I'm really just using my eyeballs as the colorimeter.
Yup and that’s all fine if the goal is a visual match to the print. That’s what most of us are after.
-
Andrew,
Thanks for your time and explanations. I'm still wondering if I should just exchange the colorimeter.
Have you noticed much sample variation in colorimeters or do you think I'm barking up the wrong tree? :)
Jeff
-
Have you noticed much sample variation in colorimeters or do you think I'm barking up the wrong tree? :)
Not having more than one sample of product, I can’t say. But I suspect that by altering the WP values, you’ll end up with a target that works.
-
Try to calibrate the display to D65 without a sensor using NEC Multiprofiler software, and tell us if the green cast is still there.
I just profiled using the Multiprofiler software and no sensor and the result was a slightly greener cast than when I use the Spectraview II and the NEC Colorimeter.
-
You have to adjust the white point using x/y custom values. See: http://www.luminous-landscape.com/forum/index.php?topic=55782.new#lastPost:
When people report their display is too green/magenta, the fix can be zooming in on the central white point of the CIE xy diagram in the SpectraView software. It will give you a better idea of how changing the x and y values will affect the white point. If the screen is too green, you‘ll want to move the white point down and to the right (vise versa for magenta). Make tiny adjustments (i.e. 0.002) and recalibrate. Understand that this only works if the calibration software allows you to enter specific CIE xy values.
Andrew, I apologize for not understanding the Spectraview II software better, but I've been through the manual and I'm still not sure how to do what you've suggested.
From the main control window if I go to Edit>Target Settings>Edit (under White Point), I get a dialog box with a radio button for CIE coordinates, which shows x - 0.3127 and y-0.3290.
(http://jkott.zenfolio.com/img/v14/p973508460-3.jpg)
I can raise or lower those values in increments of 0.001, but which way is "down and to the right"? Is this the correct dialogue box? Do I put the sensor on and click measure?
Thanks in advance for your assistance.
-
White Point>Custom, click on Edit button.
-
White Point>Custom, click on Edit button.
I still don't follow.
From the main Spectraview II window under Edit, I go to Target, then I get the Edit Calibration Target, under White Point I click Edit and I get the Custom White Point window that I showed above. Correct?
Now what - what values are down and to the right to reduce the greenish cast?
-
You might want to consider downloading the free NEC 'Multiprofiler' software. That has an XY color coded CIE graph taht you can move the target value cursor to any position you want. The Spectraview software doesn't have that, only the XY input boxes which is why you're confused :)
-
You might want to consider downloading the free NEC 'Multiprofiler' software. That has an XY color coded CIE graph taht you can move the target value cursor to any position you want. The Spectraview software doesn't have that, only the XY input boxes which is why you're confused :)
Yes, Andrew has me very confused. I thought I made it clear that I was in the Spectraview II software and he didn't mention that I had to go into the MultiProfiler.
I followed your advice and went into the Multiprofiler software, Custom>Full Custom>
then, selected the memory location to be "Spectraview II";
then, went to the White Point setting and dragged the little blue ball down and to the right a teensy bit which gave me a "Correlated Color Temp" of 6680 and clicked "Finish" and now to my eyes the whites on screen look more white and less green to me and they look more like the whites on my prints.
What I don't understand is how the MultiProfiler software correlates to the Spectraview II. If in two weeks I recalibrate using the Spectraview II and my Colorimeter will it undo the change to the white point that I made in the Multiprofiler software? And then do I have to go back into the Multiprofiler to redo the white point?
Thanks for your advice.
-
You don't technically *have* to go into Multiprofiler but it's a whole lot faster ultimately.
Multiprofiler is open-ended 'setter' w/o any ability to actually calibrate (ie. use a puck for closed loop feedback) but it's nice because it's interactive (although it seems to need a few bugs squashed which make using it a bit of a pain)
Once you find the correct white point, scribble down on a Post-It :) the XY coordinates. Put those #'s into Spectraview as the target white point for the calibration. You could easily create a setup file/condition in Spectraview so that all you need to do is select that setup and press Calibrate.
-
I still don't follow.
(http://digitaldog.net/files/xy.jpg)
-
You don't technically *have* to go into Multiprofiler but it's a whole lot faster ultimately.
Multiprofiler is open-ended 'setter' w/o any ability to actually calibrate (ie. use a puck for closed loop feedback) but it's nice because it's interactive (although it seems to need a few bugs squashed which make using it a bit of a pain)
Once you find the correct white point, scribble down on a Post-It :) the XY coordinates. Put those #'s into Spectraview as the target white point for the calibration. You could easily create a setup file/condition in Spectraview so that all you need to do is select that setup and press Calibrate.
Howard, that makes sense. Thanks for clearing it up for me.
-
(http://digitaldog.net/files/xy.jpg)
As you can see above, I had no trouble finding the suggested dialogue box.
For anyone who may stumble on this thread later on, as Howard pointed out above, unlike the custom white point setting in the NEC Multiprofile software, there is no way to physically move the white point down and to the right in this dialogue box. To accomplish this objective in the Spectraview II software, you have to input lower x and lower y CIE Coordiantes to "move the white point down and to the right" and if you have a magenta cast you would input higher x and higher y coordinates to "move the white point up and to the left."
-
Jeff, I was a total failure at math ::)
but I seem to recall plotting graphs from way back in the day
Changing the numeric value of the x coordinate (negative or posative) will move the target 'point' left or right.
Changing the numeric value of the Y coordinate " will move the target point up or down.
Coordinate the two and you can move your target point straight across at any given y axis, straight up or down at any given x axis, or in any direction diagonally, by the correct input of both X & Y.