"Bill Hilton" wrote in message
Mike Russell writes …
[Jon]’s problem with externally viewed images being substantially darker presents an interesting puzzle. I don’t think it can be explained merely by a bad device profile.
Of course it can … he gave plenty of clues … it may indeed by something else but evidence suggests otherwise …
Clue 1 – "This is recent, and I caused it yesterday when I was messing with
the color settings." … he isn’t specific as to what he was "messing" with but when you build a monitor profile first you ‘calibrate’ the monitor by getting it to a known state, then ‘characterize’ it by measuring colors … the profile is only accurate for that known state, once you start "messing with the color settings" you’ve invalidated the profile and need to generate another one.
The specific problem is that Photoshop displays a significantly brighter image than Save for Web. Changing the controls on the monitor will not affect this comparison, since all images will be equally affected. A bad monitor profile would explain this, but Jon has stated that he re-created the profile using a gamma of 2.2. IMHO this means the problem may not be due to a bad monitor profile..
Clue 2 – "Only when I go into system32/spool/color/ and delete the *.icc I created does this problem go away." … what can I say? Obviously this means the profile that was deleted was inaccurate …
The profile could be fine. This clue does show that he has re-created the profile at least once, and Jon has said that he specified a gamma of 2.2. Since Photoshop must remap from a lower to a higher gamma value to display a brighter image, I think it’s worth checiking his working space profile, sRGB. Adobe Gamma, among its other virtues, makes it very easy to clobber the wrong profile.
Clue 3 – "I have disabled Adobe Gamma loader from starting at bootup, and tried different color settings, but this is still occuring." … disabling Gamma loader means the system is picking up some default monitor profile of unknown origins.
The System profile will be in place in any case. Adobe Gamma Loader is responsible for initializing the video LUT to the values specified in Adobe Gamma.
… you can check to see what this
profile is with Edit – Color settings – in ‘working spaces: RGB’ box scroll to the top and see what’s listed beside ‘monitor RGB’ … this is the profile being used.
Not exactly. The string listed beside monitor RGB is a copy of the description of the profile that Adobe Gamma loaded initially. It would be nice if Adobe appended a "modified by Adobe Gamma" to the end of the description, but since it doesn’t, this string is not a reliable way to determine the monitor profile.
In addition, this profile is not the same thing as the System’s display profile, but a separate profile used by Adobe products for display conversion purposes. The system display profile is in the Monitor settings for Windows 2000 and later. Adobe Gamma normally keeps these in sync, but it’s possible to manually change things out from under the Gamma Loader. I don’t think this is Jon’s problem, BTW.
Clue 4 – he wasn’t clear about what he meant by "saved" in Photoshop but the link he provided showed the difference between an image displayed in Photoshop and the same one in the ‘save for web’ window of ImageReady … the ImageReady window shows how the image will look on the web without the monitor and working spaces profile, otherwise there’s no difference. Again, this narrows it down …
It certainly does.
If it is, then what would be the simplest way to verify this?
Generate a new, accurate monitor profile (and if you "mess with the color settings" again then generate a new profile) … make sure Gamma loader is enabled if you use Adobe Gamma, or disabled if using a hardware solution since their software will load the profile, and check that this profile is picked up. That should do it.
If you want to see the effect the monitor profile has in Photoshop then open an image like the test one and do View – Proof Setup – and choose ‘monitor RGB’ … this ignores the monitor profile … then do cntrl-y to toggle this on/off, showing you the effects of applying the monitor profile … if the image is sRGB then you should see just a slight shift in the saturated colors if you have a good monitor profile … if you’re seeing a wild jump in colors then the monitor profile is bad … so Jon, can you try this? I’ll bet you see the image look very similar to what you get with ImageReady when you do ‘save for web’ …
Good idea. I’d also like to get hold of one of Jon’s files. If it displays too light on my system, I’ll know it’s a problem with the embedded profile. If it doesn’t, then the problem has to be, as you suspect, somewhere in the display setup.
The moral of the story, I think, is that color setup is too arcane. It’s ironic that one of the oldest computer peripherals is still not truly plug and play. We are waiting for an Alan Oppenheimer of color to make sweeping simplifications to the setup process.
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Mike Russell
www.curvemeister.com