A problem with colour profiles

[Mister]

Hi guys,
I have a daunting problem with colour profiles and I hope that someone can help me. I'm sorry to ask for advice at my second message but it's driving me crazy.

I have a Macbook Pro and a new iMac. Both use identical colour profiles, and in both Photoshop colour settings are identical.

For some reason I cannot fathom, the iMac produces images that online and on all other computer are displayed with very different colours, whereas the Macbook Pro seems to do fine.
Here is an example of the colour discrepancy:

All the imaging software I use has this same problem: Photoshop, Lightroom, Skitch. For some reason, the «Save for the web» function in Photoshop seems to be the only one to produce accurate images (as you can see in the previous example).

Does anyone know what this can be due to?
Thanks to everyone

A.
______________

These are the colour profiles I'm using and the Photoshop colour settings

 

[lightbrush]

you did not say whether you have calibrated your mac.

 

[Mister]

I haven't calibrated it, but I can hardly see calibration being the problem with such an enormous difference. Moreover, 'save for the web' seems to be giving the right output anyway.

A.

 

[LittleWolf]

Your description is a bit ambiguous - do you adjust the pictures to look visually the same on both computers, then you save it, and the files end up very different? This would point to using bad/wrong display profiles. Or do the pictures end up different even if no adjustments are made? This would point to wrong profiles being embedded in the saved picture.

One of the likely candidates is that in your screenshot, you selected sRGB as the display profile, not the iMac profile. The display profile should reflect your monitor.

 

[Mister]

Hi LittleWolf, I did not adjust the pictures to lok the same on both computers. In fact, they don't. I noticed it when pictures i posted on flickr with the iMac appeared significantly more dull when viewed on other monitors (including that of the Macbook Pro, which anyway has the same settings of the iMac).
I apologise for not being clear, but the problem is not clear to me either, and its "symptoms" are not very straightforward to analyse or describe.
Yes, I did choose the sRGB profile over the iMac initial profile, but that is because the initial Mac profile is significantly more warm then it should be (going back to the original iMac profile does not solve the problem either).

Thanks

Andrea

 

[LittleWolf]

In general, there should be 4 colour spaces involved: 1) the colour space of the original file, 2) the working colour space of the software, 3) the colour space of the display, and 4) the colour space of the saved device.

1) _could_ be an issue if on one computer, the original file is interpreted in a different colour space than on the other. I'm not sure where/how this is configured in your software, but there might be a setting like "respect/ignore embedded profile".

2) should be easy to check - one of the screenshots you posted showed the working space configuration. Just check for consistency in both setups.

3) seems unlikely if the results differ even without editing, but just opening and re-saving the file.

For 4), you could check what/if any profiles get embedded in the files you save. I'm not sure about software choices on the Mac to do this (though it should be easy to find unix-based utilities that you can run from the command line). This could help to find out whether the problem is with different picture data in the files, or merely different colorimetric interpretation of the data in the files.

 

[lightbrush]

I haven't calibrated it, but I can hardly see calibration being the problem with such an enormous difference. Moreover, 'save for the web' seems to be giving the right output anyway.

A.

it's kinda hard to say what the problem is unless you baseline it first. I think, whatever it's worth, calibration will be the 1st step I'd do before moving on to consider other factors.

 

[Mister]

In general, there should be 4 colour spaces involved: 1) the colour space of the original file, 2) the working colour space of the software, 3) the colour space of the display, and 4) the colour space of the saved device.

1) _could_ be an issue if on one computer, the original file is interpreted in a different colour space than on the other. I'm not sure where/how this is configured in your software, but there might be a setting like "respect/ignore embedded profile".

2) should be easy to check - one of the screenshots you posted showed the working space configuration. Just check for consistency in both setups.

3) seems unlikely if the results differ even without editing, but just opening and re-saving the file.

For 4), you could check what/if any profiles get embedded in the files you save. I'm not sure about software choices on the Mac to do this (though it should be easy to find unix-based utilities that you can run from the command line). This could help to find out whether the problem is with different picture data in the files, or merely different colorimetric interpretation of the data in the files.

Hi Wolf,
I checked all four, and everything seems consistent and at the right place. The problems seems to be outside photoshop itself though, since also lightroom Skitch and (I downloaded it just to check) also Pixelmator have the same behaviour.
If only it was a laptop I'd take it to a technician

 

[LittleWolf]

Hi Wolf,
I checked all four, and everything seems consistent and at the right place. The problems seems to be outside photoshop itself though, since also lightroom Skitch and (I downloaded it just to check) also Pixelmator have the same behaviour.
If only it was a laptop I'd take it to a technician

If you start with identical files, do exactly the same things with them, save them in exactly the same way, and get different results, it looks like a configuration issue. Maybe check if there are any system-wide configuration settings that might be "inherited" by whatever software you use?

Maybe you could also post tiny sample pictures (not screenshots, so that embedded profiles are preserved) for comparison? I.e., one tiny image file that gets processed exactly the same way on both computers, and the resulting files from both computers?

Sorry if I cannot help.

 

[Mister]

I think I found my solution here – apparently it should be a quite widespread problem

http://www.gballard.net/psd/saveforwebshift.html

Thanks everybody