I started a thread about this previously (9 months ago), but it was never resolved, and since I have more information now, I think it makes sense to try again.
Previous thread: http://www.zenphoto.org/support/topic.php?id=4937
So the problem is that color profiles are not maintained through ZenPhoto's processing. If you display an original image that has not been resized, then the profile is honored (by browsers that can see it) since ZP just sends the whole file through, but as soon as you do something to the file (like make it into a thumb or resize it), then the new versions are stripped of their embedded profile. Because of this, it has been recommended in many places to upload photos that do NOT have embedded profiles, but have been "converted" to the sRGB space. Unfortunately for some (me included), this means adding an extra step to the workflow. My current workflow uses LightRoom, and I export directly from there and then upload. Frustratingly, however, it is not possible to export from LightRoom without attaching a profile.
So far, I have discovered the following:
-
If you "Export" from LightRoom using the sRGB setting, then the following are true:
-There IS a profile embedded in the file
-The file looks significantly different when viewed in profile-aware browsers as opposed to profile-ignorant browsers. Specifically:
-On monitors calibrated to a wider color space than sRGB, it looks great in profile-aware browsers and too-bright on profile-ignorant browsers.
-On uncalibrated monitors (basically using the sRGB space), it looks too dark in profile-aware browsers and good in profile-ignorant browsers. -
If you open the above file in Photoshop, and either "Convert" to sRGB or "Save for Web" using sRGB, then the following are true:
-These is NOT a profile embedded in the file
-The file looks the same in all browsers. But unfortunately:
-It looks good on uncalibrated monitors (basically using the sRGB space); and
-It looks bad on monitors calibrated to a wider color space than sRGB (too bright).
The evidence that I have that indicates that the first file (#1 above) has an embedded profile and the second file (#2) does not:
-Opening the files in PS yields messages that indicate that #1 one has an embedded profile (sRGB) and #2 one does not
-Examining the files with other file utilities yield the same result
Ideally, of course, I would like a solution that:
-looks fine in profile-aware browsers on calibrated monitors (like #1),
-looks fine in profile-ignorant browsers on calibrated monitors (like #2); and
-looks fine in all browsers on uncalibrated monitors (like #2).
I can only assume that many other LightRoom users have the same problem, though I imagine that some of them don't even know that they do. I am noodling the best way out of this mess, but I certainly don't have the right answer yet. Any input/ideas would be most welcome.
This is of course no real Zenphoto issue as the GDlib does simply not preserve profile. It also depends on the Gamma setting. For example Macs were – before OSX 10.6 - traditionally set to 1.8 while Windows always used 2.2.
Color management is generally not a simple thing, neither web nor print. At least the latter generally supports profiles (nevertheless fool proove is something else...:-)).
For me it indeed generally works to simply use sRGB for the web and export using the "web" function of PS (if not sRGB of course converting - not assigning! - to that profile first).
I agree that it is not a ZP "issue." Nonetheless it impacts ZP users. And it probably impacts more of them than actually realize it.
I agree that converting everything to sRGB is the obvious solution, and a good starting point. Ironically it doesn't end up looking good on calibrated monitors using profile-aware browsers. I say "ironically" because those are the "high rent" versions of both monitors and browsers, and they end up looking the worst by using the lowest common denominator solution.
It also seems VERY strange to me that it is not possible to export from LightRoom without a profile.
I think it's also safe to assume that as time marches forward, more and more browsers will be profile-aware and more and more monitors will have wider color capabilities. So it would be good to use a solution that is somewhat more future-ready than simply bashing everything down to sRGB.
Calibration itself is of course still relative, too. There is also the software calibration and the real hardware calibration using Spiders and such tools. Also where the monitor is located, how is the surrounding light etc. impacts the display of the color.
Also I doubt that most of the ZP users (and especially the casual visitor of the sites itself) have really hardware calibrated and also those quite expensive "prepress" monitors with the best possible color range as those cost a multiple from "normal" monitors.