[badidea]

I recently discovered that I have a weird color/gamma problem in Safari and Preview!
When I look at the small picture thumbnails on webpages they look like they have the right brightness but when I open them they are way too dark.
The same effect happens when I download such an image and look at it in Preview.app.
Graphicconverter doesn't have this problem - the picture looks alright there!


I already checked my system prefs but they seem to be alright.
I have seen this with JPGs and PNG images so far but sometimes they look ok (not very often though)...

What could have happened??
What can I do now?


Makki's screenshot here does have this problem: http://www3.sympatico.ca/ilife/appleapple.png
My own screenshot is ok: http://www.badidea99.de/clean.jpg

[badidea]

update: no problems on another user...

...but still cannot find what's causing this...

[Millennium]

I've never heard of this problem with JPEGs before, but it's a well-known aspect of PNG which has caused quite a bit of controversy in the past. It has to do with the gamma settings on Windows and Mac monitors. The crux of the matter is that Windows sets its gamma much too dark, such that images come out on Windows with greatly distorted color. Of course, to a Windows user this looks fine, because that's what they're used to. However, it's a common complaint among Windows users that when they browse the Web from a Mac everything is too bright.

Most images don't bother stating what gamma they were used to create. When that happens, the image is rendered using the OS' native gamma, and the image comes out looking more or less OK. However, PNG images (and, more recently, JPEGs) can specify the gamma of the machine which created them, and many do. When this happens, the computer is supposed to alter the image's colors as displayed, to compensate for the shift in gamma. In theory, this leads to images which show exactly the same colors across platforms. You are seeing the image as a Windows user would see it. Not all images do this, but many PNGs do, and nowadays some JPEGs do too.

Several years ago, Mozilla decided to start doing color correction on not only images but also Web pages (the CSS standard defines a method for doing this). Personally, I loved it, but many Mac users complained about pages being too dark, so they removed the feature, and most browser makers have followed suit. Safari doesn't correct Web page and image colors for this same reason, bot only as long as you're viewing a Web page. Most other Mac apps perform this correction, and Safari does it too if you use it to view an image as opposed to a page. That's the issue you're seeing.

If I'm correct, and these images were created on Windows, then what you're seeing is not a bug. The creators of these images specified their monitors gamma (hopefully on purpose but perhaps by accident) when they created the images, and the Mac is recoloring them to fit that monitor. Assuming that both monitors are properly calibrated, you are seeing the image exactly as its creator saw it. You probably should calibrate your monitor anyway; the difference a properly-calibrated monitor makes on things like readability is amazing.

[badidea]

Well, thanks Millenium for your long answer but I already knew what you are talking about (not as detailed though) and the problem started just recently (2-3 days)...
...and why isn't it happening on another user then??!!

The images are so dark that I just can't believe that some Windows user would accept this (and I know how browsing with Windows looks like)!

[badidea]

WOAH, wait a second - I think I just solved my problem!!!

Not in a very good way though!

I had also tried to fix my permissions and the following came up:
-----
Repairing permissions for “OSX”
Determining correct file permissions.
We are using special permissions for the file or directory ./Library/ColorSync/Profiles/Displays. New permissions are 16893
We are using special permissions for the file or directory ./Library/ColorSync/Profiles. New permissions are 16893
We are using special permissions for the file or directory ./System/Library/Filesystems/cd9660.fs/cd9660.util. New permissions are 33261
We are using a special uid for the file or directory ./private/var/at/jobs. New uid is 1
We are using a special uid for the file or directory ./private/var/at/spool. New uid is 1
The privileges have been verified or repaired on the selected volume

Permissions repair complete
-----
Now you might wonder why I can still copy paste this even though I already repaired all that stuff?!
Well, that's because I had to realize that it never really got repaired!

That's why I logged in as root and deleted the standard display profile manually...that was the bad idea, because now I am not allowed to recalibrate my display anymore...

...but my problem is gone!!

(now I just have to find out how to reinstall colorsync)

[Millennium]

ColorSync-related issue, then; I suppose that's not too surprising. That's the kind of issue one would expect to find.

If you need to restall just ColorSync, you should look into CharlesS' software "Pacifist". I've never tried using it to reinstall only ColorSync, but it should be able to do that.

[badidea]

Didn't need to reinstall - I still had the profile in my root trash!

Now I just have to find out how to fix all those permission issues you see above because neither root nor my admin user can really fix them with DsikUtility...