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Author Topic: JPEG artifacting in dark areas on some browsers  (Read 4183 times)
feppe
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« on: July 24, 2010, 02:20:18 PM »
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I've been updating my site with the excellent LR3 publish feature, and noticed very ugly JPEG artifacting in deep blacks (less than 1% RGB values) on some browsers. The artifacts are not visible in LR3 or Windows built-in viewer.

First I thought it's export quality settings: I recently lowered my exports to 75 quality. Jacking it up all the way to 100 helps a bit, but doesn't eliminate the artifacts.

I tested with four browsers: FF and Safari (PC) had the worst artifacting, while Opera and IE had almost none. This suggests the blame is on the browsers (FF and Safari).

Below three samples. The Hong Kong skyline shows the worst artifacts in the upper left corner, Castellammare del Golfo on the left quarter, and the ice carver on his shirt. Can someone verify they see the artifacts - perhaps my monitor or calibration is out of whack. Of course you will have to view them with Safari or FF to see what I'm talking about.

Is there anything I can do?

Found the culprit!
« Last Edit: September 17, 2010, 02:18:55 PM by feppe » Logged

madmanchan
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« Reply #1 on: July 24, 2010, 03:16:44 PM »
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Hi, FWIW I don't see any artifacts on my display here (using Firefox 3.6.8 on Mac OS 10.5.Cool. Display is NEC MultiSync LCD 2690WUXi.
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Slobodan Blagojevic
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« Reply #2 on: July 24, 2010, 05:07:14 PM »
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Can not see any artifacts either (Safari on iMac 24")... but than again, at such a small size (800 px) it may not be even possible to see it.
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k bennett
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« Reply #3 on: July 24, 2010, 05:38:29 PM »
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Looking at your photos on a new 17-inch MBP using Safari, they look fine. No artifacts, no color problems, nothing wrong at all.

Are you viewing them with a wide gamut monitor?
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feppe
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« Reply #4 on: July 24, 2010, 06:05:37 PM »
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The artifacts are clearly visible at this size.

Not a wide gamut monitor.

Anyone on Windows?

edit: checked on my work Windows laptop, and there are no visible artifacts in IE or FF. So the good news is there's probably nothing to worry about.

Likely something to do with monitor calibration - I re-calibrated and they're still there. I wonder why the artifacts are visible only on some browsers.
« Last Edit: July 24, 2010, 06:26:27 PM by feppe » Logged

Gary Brown
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« Reply #5 on: July 24, 2010, 06:31:56 PM »
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I didn't notice any artifacts, either, but FWIW, in Jeffrey Friedl's An Analysis of Lightroom JPEG Export Quality Settings, he makes a comment that “Firefox does not handle display of JPEGs very well, sometimes introducing horrible posterization that does not actually exist in the image.”

See also a few of the comments beneath that post (search for “Firefox”), but there's no real conclusion about it.
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Alan Goldhammer
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« Reply #6 on: July 24, 2010, 06:48:14 PM »
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I'm on Windows 7 with Fire Fox (NEC P221) and they all look fine to me, though as a previous poster noted it may not be possible to see flaws at this resolution.

alan
« Last Edit: July 24, 2010, 06:48:54 PM by Alan Goldhammer » Logged

feppe
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« Reply #7 on: July 24, 2010, 07:01:12 PM »
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Quote from: Gary Brown
I didn't notice any artifacts, either, but FWIW, in Jeffrey Friedl's An Analysis of Lightroom JPEG Export Quality Settings, he makes a comment that “Firefox does not handle display of JPEGs very well, sometimes introducing horrible posterization that does not actually exist in the image.”

See also a few of the comments beneath that post (search for “Firefox”), but there's no real conclusion about it.

That's actually the article which prompted me to change to lower export settings  Didn't notice the blurb about the posterization, there are several comments about the issue, and further googling confirms I'm not the only one who ran into this. Whew...

I played around again with Gary Ballard's exhaustive browser color management page, which confirms FF and Safari are color managed. Opera is not color managed, same with IE. Perhaps FF's and Safari's schizophrenic approach to color management is the reason for the artifacts?

and another edit: found the culprit!

Gary Ballard's page linked above put me on the right track: newest FF has color management on by default. The entry gfx.color_management.mode in about:config is at 2 (enable color management for tagged graphics only) by default. Setting it at 1 (enable color management for rendered graphics) still has artifacts, but at 0 (disable color management) they are gone!

Given that FF and Safari are  color managed and show artifacts, while Safari and Opera are not color managed and artifacts are absent, the blame is on color management, or its implementation at some point in the input-output chain. Perhaps this is just a result of a (yet another) half-assed implementation of color management in the browsers.

Does LR3 embed the ICC profile in JPEGs on export?

Quote from: Alan Goldhammer
I'm on Windows 7 with Fire Fox (NEC P221) and they all look fine to me, though as a previous poster noted it may not be possible to see flaws at this resolution.

As I pointed out they are clearly visible at the res posted.
« Last Edit: July 25, 2010, 08:01:47 AM by feppe » Logged

madmanchan
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« Reply #8 on: July 24, 2010, 08:37:17 PM »
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Hi, yes, LR does embed the ICC color profile into the JPEG on export.
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