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Changing gamut creates horrible reds

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  #31  
Old 05-07-2013, 11:17 AM
matthiassebas matthiassebas is offline
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Re: Changing gamut creates horrible reds

Unfortunately the problem seems not to be a handling error. Instead it seems to be an effect connected to driving a wide and a standard gamut monitor from a Mac at the same time when handling untagged sRGBs.

Tests before showed that sRGB-8bpc files in Safari (and other browsers) displayed a heavy red colour cast if untagged on the MacBook Pros LCD (sRGB gamut) and on Eizos CG243W (wide gamut).

From my point of view this result was not in line with the explanation Safari assigns the display profile to the untagged file as in the case of the sRGB display this shouldnt result in a red colour cast if the profile of the sRGB device would have been assigned.

Nevertheless Rob Griffith suggested to test with sRGB-8bpc files tagged and untagged with the Eizo CG243W attached and also detached from the MacBook Pro.

As before in this test the red colour cast was visible on the MacBook Pros LCD as long as the Eizo was present. Nevertheless after a restart and detaching the Eizo the colour cast was gone on the MBPs LCD!

Also reattaching the Eizo via Thunderbold after the MacBook Pro was started without it (not showing the colour cast) introduced the colour cast on both displays upon moving the files once onto the Eizo!

So it seems that the presence of a wide-gamut display can change the behaviour of a sRGB display device also connected to a Mac wrt displaying untagged files.

Also it brings in line the explanation that Safari might not handle properly untagged sRGBs on wide-gamut displays because its stretches sRGBs to the gamut of the wide-gamut display (or via a similar mechanism e.g. tagging the file with the profile of the wide gamut display which might result in the same effect) and by doing so introducing the red colour cast. My understanding is that this is what andrewrodney and Rob Griffith (via phone) have explained.

Many Thanks to Tony W, andrewrodney, ksparticus, mistermonday and Rob Griffith of NativeDigital.com and all the others who helped.

Last edited by matthiassebas; 05-07-2013 at 01:01 PM.
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  #32  
Old 05-07-2013, 01:36 PM
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Tony W Tony W is offline
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Re: Changing gamut creates horrible reds

Quote:
Originally Posted by matthiassebas View Post
... Instead it seems to be an effect connected to driving a wide and a standard gamut monitor from a Mac at the same time when handling untagged sRGBs.
Ahh, I did not see the fact of driving two very different gamut monitors from the same Mac mentioned in your posts!

Lesson learned always use tagged images

Glad that the issue is now resolved
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