If the two images above look exactly the same to you, move along; this blog post doesn’t apply to you.
Note: I posted a follow-up to this going into a bit more detail on one angle of this.
For much of my workdays, I’m using a Dell 24″ monitor to do most of my work, hooked up to my Mac laptop. For color fidelity, it turns out this has been rather painful. For some reason, this setup has caused me to experience all kinds of weird color glitches, such as the one at the head of this post. At first, I thought this was just colors rendering differently on the external monitor and the laptop’s internal display–but unfortunately, it’s more than that.
The same colors on the same display differently under certain conditions. Here’s another fun example:
This is more than just really annoying. When working on Bespin recently, I discovered that the slice images I’ve made from our designer’s source files contain different color values than what he initially specified. At least, some of the slices do. The slices are in fact inconsistent due to this same problem. Argh!
I’ve checked OS X’s System Preferences and the Dell is using its own Color Profile; isn’t this the right thing for it to be using? Why am I getting this behavior?
My guess would be that a Carbon/Cocoa Window, when displayed, uses the settings of the display on which it initially appears, but when you move the window from display to display, either the application is responsible for detecting the event and responding to it, or OS X has bugs in properly managing the shifting settings?
Does anyone know how I can fix this problem? Maybe I just need to start working on Apple displays again… or limit myself to one monitor and class the laptop display at work.
UPDATE: Because several folks were confused about what exactly I was showing in the Terminal screenshot above, I replaced it with something that may illustrate the problem a bit more clearly. Look at the text in the Terminal graphic. See how the shade of green is different? This is not because of foreground/background windowing issues. The color green is different, even though its the same theme, etc. These are not screenshots from different displays sewn together; they are running on the same display; so this isn’t to do with embedded color profiles in images, etc.
Ben Galbraith 
Hey,
do you have a current-generation Apple Macbook Pro?
With my 24″ Dell monitor I have really weird issues. Especially random white pixels occuring. They get less as the monitors warms up. The results vary based on the quality of the DVD cable.
Also when I connect any VGA monitor the laptop freezes and won’t come up again until you disconnect the cable. Restarting with the VGA device connected works. Really feels like 1998.
Cheers
Malte
Ben,
Been enjoying your blog on Bespin. I’m very impressed and excited by the project and possibilities it presents. Well done and I look forward to following how things unfold.
I’ve had similar issues with being an OCD designer with multiple displays. I bought a color calibrator (colormunki photo ~ $400) and I have never had a color matching issue since. Color calibration is an INSANELY complicated topic and becomes too heady too quick. I can send you the profile from my 2405FPW for you try (if that’s what you have) but unfortunately the monitors need to be calibrated every 1-2 weeks or things like what you’re showing in the top comparison of two photos happens again.
For years I thought this calibration stuff was a scam. It’s now a piece of hardware I swear by. I am very very wary of what causes these shifts in color production. I’ve been told that the monitors undergo physical changes over time necessitating the calibration.
This all said, if I were to do it again, I would have seriously considered the Chroma 5 or X-Rite i Pro (~500 and ~800 respectively). As this is a one-time purchase, I wish I had gone with something less consumer-ish and more technical. There is a 3 MAC ID limit on the colormunki which IMHO is absolute garbage.
Hope this helps a little, there is an overwhelming amount of information and SO MUCH misinformation on the web about this stuff. It is daunting and frustrating to deal with, if you have questions that my past homework might be helpful feel free to shoot me an email.
mgs
I found these sites to be absolutely the most informative. The first link also has a storefront with I believe the best prices on a few of the models. I didn’t purchase from them but I would in the future.
http://www.curtpalme.com/forum/viewtopic.php?t=10457
http://www.northlight-images.co.uk/reviews/profiling/colormunki.html
http://www.northlight-images.co.uk/leicester_colour_management.html
.mgs
@Malte: Yup, late-model 17″ MacBook Pro (right before current gen). I haven’t seen the issues you’ve described, but they sound frustrating!
@Michael Simpson: Thanks for the detailed information! Do I really need to do color calibration if I don’t care about fidelity with print? I don’t even necessarily care about how closely my monitor approximates others. I don’t even care if the laptop’s internal display looks different than the external display.
I just want image palettes to be consistent in the bitmap itself. How does calibration help this?
And, thanks for the kind words!
Does the ICC profile remover work(http://www.colormanagement.com/technical_resources/files_targets_and_utilities/mac_os_x_scripts/)? Or is there a way to disable color profiling completely in OS X?
I’ve anyways never understood why the profiles are stored together with the images. To me they should be a property only of the devices, not the images as such. Those should adhere to some “global profile”.
Regarding the Terminal images, note that the greens appear different because the lower one is on a darker background (the terminal background is translucent).
@Tom von S.: Oh, if only that were true.
@Arthur: Then what do I do when the contents of the window are not an image, but are different colors?
Here’s a good summary of the problem.
http://photo.net/digital-darkroom-forum/00PZtm
@Ben, ahh I see. Odd, the one on the left is #0f0 but on the right it’s #00ff0a.
Man, I know your pain. I recently had to send back a Dell 2408WFP because the colours were so bad with my MBP I couldn’t take it. No amount of calibration could fix the problem.
Now Apple has screwed me over by killing off any monitors that would work with my laptop, and I really can’t find a suitable alternative.
Colour is hard, and done so badly by so many monitors these days.
Dave
are your displays proper calibrated?
Ben, I would guess that one image has a profile attached and the other doesn’t?
As far as I can remember, OS X will auto tag untagged images with the profile of the monitor they came from.
In the case of your designer, you might try a few tests with sRGB tags on the images in question. I remember that we had issues with css layouts where we’d use an image that was tagged sRGB and then one that wasn’t, and if you viewed in Safari, one matched and one didn’t.
In the case of your monitors, I’m guessing that the different profiles in use for those monitors then auto tags the images with the profile of the monitor they came from. I think you can test this by doing a screen grab from each monitor and then viewing the image data. If I’m not too far off, you should see one each image tagged with the profile of the monitor they came from.
Use the displays system preference panel and set both displays to use sRGB and things should be OK unless you want to go with the full hardware color calibration route.
Ben,
In your second example (terminal) if you are referring to the difference in the grey in the title bar, it’s because its the active window. OS X makes the background windows title bar a different shade.
To answer Arthur’s question (“I’ve anyways never understood why the profiles are stored together with the images… Those should adhere to some “global profile”.) the profile must be stored with the document because it describes the colour space that was used in creating it.
@Bradley: I’ll try that, thanks man.
@Steve: I updated my post to clarity that I’m referring to the color of the text in the Terminal windows, and that these are side-by-side Terminal windows running on the same display–so embedded color profiles in screenshot images aren’t to do with the problem.
You probably want to set both monitors to same gamma, sRGB profile. This is a nice backgrounder: http://blogs.smugmug.com/don/2007/02/14/this-is-your-mac-on-drugs/
Isn’t the macbook, like the cheaper end imacs, actually using dithering? That is, Thousands of colors rather than Millions?
Caused a big stink, because Apple had not done that trick in some time. Dunno if you can, like in the OS 9 days, lower the native resolution of the monitor to show more colors.
@bud: Maybe the MacBook is, I dunno. I have a top-of-the-line 17″ MacBook Pro, so I don’t *think* that’s the issue…
Yes, Apple allows you to choose separate color profiles for each monitor, the Dell and the laptop. You should calibrate each screen. If you don’t have a 3rd party hardware calibrator, then you can do an approximation by using the software calibrator built into System Prefs, under Display.
My experience with Dell displays are that they are BRIGHT! and need to be toned down, you may need to push a bunch of buttons on the screen to get the screen brightness down. You may actually have to fiddle with each RGB color channel. The calibration process, above, should indicate whether that is necessary. It’s usually, the first step, getting the brightness and contrast right, so you get the most dynamic range out of your monitor.
Lastly, the Dell, being a desktop display, is going to have a wider color gamut than a laptop display.
Oh, did you know there’s a photographer, Rob Galbraith, who writes on these topics, extensively. You should check out his website.
http://www.robgalbraith.com/bins/index.asp
We’ve had good success with the new Spyder3 Elite. You definitely are experiencing a color space issue. If you are processing images for publication by an outside press, they should provide you with the .icc profile for the CMYK space they expect the final product to be in. Of course, this all only applies if you are using an app which is color space away, like Photoshop…
If you are just working on this at home and the difference in the displays is bothering you, display calibration should be enough – try using the color calibration in display preferences before buying anything.
…speaking to bud’s comment, the highest resolution offered for the display in OS X is always the native res of an Apple LCD… it becomes blurry the lower the res moves away from native, due to clusters of pixels being used to “dither” or approximate larger physical pixels… switch to 800×600 and look closely.
I’d go along with Michael and consider the profiles and perhaps even using a color calibrator. One other quick issue may be the gamma, as rentzsch mentioned.
Mac OS X will attempt to create a color profile for a monitor that you plug in, based upon information that the display gives in it’s EDID. However, this information is mostly the same for all models of a display and, therefore, is really only a starting point–sort of a “good enough” situation. Again, display calibration is key if you want things to look good on both displays.
I’d like to know about those two image examples you show here. How did they come to be displayed on the page as a single image each? Did you composite them together in Photoshop or some other image processing software that is ICC aware? If so, how are your color management preferences set up in that application? Did you have to respond to queries about mismatching color?
As for the comment about keeping the images separate from their profile, what happens if you send that image to a service shop for printing, while your profile sits on your computer?
Color management is a minefield full of questions instead of mines.
Hi Ben,
Change your mind set and relax . I have the answers for you.
I’ve created many Magazine Cover , CD Cover etc all over the world. The reason I’m telling this to you is not for bragging rights. It’s because I’ve tried all of this for years with nothing in the end but frustration.
I’ve finally figured out the solution . Get as close as you can on your set up, whatever that is and
adjust from a PRINTED PROOF from the printer or service bureau .
Let me explain .
1) No 2 computers will display the same colors even if they are the same models
and calibrated . ( Different vendor parts, within different vendor parts ! )
2) You can have everything preflighted ,perfect on your system bla bla bla…..
The people that you send your file to, use different model computers , monitors and set ups.
Different versions of Photoshop, Quark, indesign ……….
So you’re F%^&Ked right there.
3) Just for kicks lets say everything is the same from your output and even
the final computers out put to the printer . You still have another variable.
4) Printer , printing ink and sub straight ( Paper ) .
No 2 printers will print the same . Even if they did, the brand of inks differ in color.
Not only that , but the ink lots differ ! Then you have the paper . Type, tint color and finish .
I hope you can see my point and that this will keep you from being so frustrated.
Please feel free to email me .
Best regards,
Hal
@Hal: I must have done a terrible job writing this blog entry; I apologize.
I understand that:
– No two (uncalibrated) monitors from different manufacturers are likely to display the same color in the same way
– Printing will also vary widely in output colors; the variables are immense! Different ink vendors, different ways to mix the ink, different papers which absorb the inks differently, etc.
– Etc.
What I’m saying is, the *same program* on the *same monitor* displays colors differently, and I’m not talking about just *images*, I’m talking about, for example, OS X’s Terminal application (as displayed above).
Further, the *same* image in the *same* program reports *different* colors when I sample it (admittedly, using a separate program to sample it–Art Director’s Toolkit in this case).
I would expect applications to look different on different displays, but having the colors be different RGB values across different displays seems *wrong*, and having them be different RGB values on the *same* display seems doubly wrong.
Wrong wrong wrong.
When I mouseover your 2 terminal text examples, in DigitalColor Meter I get:
Red: 0
Green: 65535
Blue: 0
For *both*. As far as the OS knows, and what is displayed on your webpage, they are the same color. If you (and maybe I) perceive color differences between the two, it is a physiological issue of how the eyes and brain perceive color when surrounded by different colors (in this case, your window title bars).
However, the 2 pics of the girl’s face are significantly different in color as DigitalColor Meter detects them.
BTW, if the 2 face pictures are screen caps from your 2 different monitors, then that is a monitor hardware calibration issue, which I will defer to others here as I have no experience doing the kind of color managed workflow which necessitates the expense of hardware color calibration.
I have run into color problems like the 2 face pictures before in Photoshop when the Preview box is checked in Color Settings. As I drag the picture from 1 monitor to another (both calibrated only through the Displays Sys Pref), Photoshop will change the color of the pic and the mapping of the RGB values as *displayed* on the screen (not in the actual file) as I let go of the mouse after the drag. It’s disconcerting and I have that feature turned off as I am familiar enough with my workflow that I don’t want it *thinking* for me behind my back. Again, though, color is an interest of mine but not necessary enough for me to spend $$ on *real* solutions.
@Lew Z: Man, this is getting weird.
On my Mac, using both Safari 4 and Firefox 3.0.8, in the image at https://bengalbraith.files.wordpress.com/2009/04/terminalfortom.png, the green on the left is #00FF00 and the green on the right is #7EF41D. They are dramatically different.
On my deskmate’s Mac, using both Safari 4 and Firefox 3.0.8, both colors are #00FF00.
This is the *same file*.
I get the idea that an image can have embedded color profile information, and that an application can change the RGB values in an image in an attempt to get the image to appear as the author intended, but I am totally weirded-out that screen-grabbing a region on the screen of two different windows can somehow cause the color profile information to be preserved in such a way that on my system the colors appear non-uniformly different than how they appear on other systems which are identically configured (my deskmate has same version of OS X, same version of browsers, and same Dell external monitor).
That hurts my head.
I’ll bet that it has something to do with embedded color profile information and if the user has (or has not) calibrated their monitor using Displays in the Sys Prefs. I’ll run some tests with another account on my internal and external displays connected to my MacBook and see what happens…
BTW, this effect sounds familiar and I’ve seen it somewhere else (sitting in front of someone else’s Mac) but for the life of me I can’t remember where!
I’ve been frustrated with this behavior for quite some time myself. Almost the exact setup (17″ MBP and 24″ Dell 2407WFP).
For your terminal example (terminalfortom.png), do you thinktrying another capture of the two windows with transparency turned off might make a difference? Just wondering if the less than 100% opacity is playing into the color shift issue? [after writing the rest of this, and running the tests below, I can confirm the backgrounds match in color in both window captures, so the transparency is unlikely the culprit, but it seems worth removing that potential variable]
I noticed, when bringing that image into PS, that PS wanted to use it’s embedded profile (DELL 2408WFP). If I said ok, and then sampled colors, the text on the left was 00FF00, while the text on the right was 7FF61D,. The cursor on the left was 23FF18, same for the the cursor on the right! Odd. Here’s a condensed form of the values I found:
—————————-
DELL 2408WFP PROFILE
—————————-
L/R text : 00FF00 / 7FF61D
L/R cursor: 23FF18 / 23FF18
The second time I opened the image in PS, I said discard the embedded color profile (don’t color manage). I found the same results as above:
—————————-
“DON’T COLOR MANAGE” PROFILE
—————————-
L/R text : 00FF00 / 7FF61D
L/R cursor: 23FF18 / 23FF18
The third time I opened the image, I select convert to the working space (sRGB IEC61966-2.1) and the colors changed:
—————————-
sRGB IEC61966-2.1 PROFILE
—————————-
L/R text : 00FF00 / 00F900*
L/R cursor: 00FF00 / 00FF00
* Upon further inspect, the right text had a few pixels of 00FA00 tossed in the text. None of the other images/profiles had this behavior. In fact, on multiple converts, the colors moved around. See some examples of this here (I used the magic want to select the primary text color, thus leaving 00FA00):
And just to add to the color shifts, here are the same images as JPEGs with the ICC color profile embedded:
So, what have we learned?
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