Got Grass?

[Doug Brown]

Indeed and I agree...
I have learnt as well as I always look at the "Convert to profile" box which typically shows you in which space the image is currently and where you want to convert it to

Actually Morkel, the way you describe doesn't work. See the Randy Stout Loon thread (linked in one of the above posts) for the reason why Convert to Profile doesn't work.

[Arthur Morris]

Thanks Doug, You are really on top of this stuff.

But, I do have one question for you: any ideas as to why the image in Pane 1, the one that showed RGB as the color space, and the image in Pane 39, that (properly?) showed sRGB as the (embedded) color space, look and are identical???

ps: you are up early :)

[Steve Kaluski]

Hi Doug, alternatively if you are in Bridge and you click on the image, the info comes up clearly showing key info as per this showing that the original image is UNTAGGED. If the file is say sRGB this will also be clearly stated in the Colour profile line. I assume this is an alternative route to Get info, WDYT?

Cheers
Steve

[Doug Brown]

Thanks Doug, You are really on top of this stuff.

But, I do have one question for you: any ideas as to why the image in Pane 1, the one that showed RGB as the color space, and the image in Pane 39, that (properly?) showed sRGB as the (embedded) color space, look and are identical???

ps: you are up early :)

Hey Artie. Up early because someone's got to make the donuts! As to your question, the images do not look identical in the two panes if you are viewing them on a color-managed browser. As an experiment, I viewed the images in Firefox (color managed) and took screen shots of each version. Then I did the same thing in Chrome (not color managed). I then opened all 4 screen shots in Photoshop and used the color sampler tool in the exact same spot on all 4 photos, using a 5x5 average for my sample size. Here are the results (R G B).

Original image on a color managed browser: 168 191 162
sRGB embedded image on a color managed browser: 156 196 199
Original image on a non-color-managed browser: 156 196 199
sRGB embedded image on a non-color-managed browser: 156 196 199

You can see that the RGB values are identical for the images with an embedded color profile on both browsers, and also for the original image on a non-color managed browser. But the original image, when viewed in a color-managed browser has significantly different RGB values. The differences are obvious to the naked eye when I look at the images in Firefox.

Here's a screen shot from Photoshop to illustrate what I did (I used the RGB values labeled #1):

[Marc Mol]

Ah hah! Many thanks Doug.
Forgot to mention earlier Artie, a fine image with a lovely mischievous look.
TFS

[Arthur Morris]

Hey Artie. Up early because someone's got to make the donuts! As to your question, the images do not look identical in the two panes if you are viewing them on a color-managed browser. As an experiment, I viewed the images in Firefox (color managed) and took screen shots of each version. Then I did the same thing in Chrome (not color managed). I then opened all 4 screen shots in Photoshop and used the color sampler tool in the exact same spot on all 4 photos, using a 5x5 average for my sample size. Here are the results (R G B).

Original image on a color managed browser: 168 191 162
sRGB embedded image on a color managed browser: 156 196 199
Original image on a non-color-managed browser: 156 196 199
sRGB embedded image on a non-color-managed browser: 156 196 199

You can see that the RGB values are identical for the images with an embedded color profile on both browsers, and also for the original image on a non-color managed browser. But the original image, when viewed in a color-managed browser has significantly different RGB values. The differences are obvious to the naked eye when I look at the images in Firefox.

Here's a screen shot from Photoshop to illustrate what I did (I used the RGB values labeled #1):

Thanks Doug, Life was much simpler when I did not know about color managed and non color managed browsers. Your info sure explains why different folks are seeing stuff differently....

Do note however that when I viewed this post in Firefox that all of my images looked identical!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

What gives? (I usually use Chrome for convenience....)

[Sidharth Kodikal]

Hey Doug,

A few questions as I'm trying to get a grasp on color profiles:
What do you have gfx.color_management.mode set to in firefox?
Also, do you have a profile assigned to gfx.color_management.display_profile?
What version of firefox do you use and are you on a wide gamut monitor?

My hunch is that you are on a wide gamut monitor and your gfx.color_management.mode is set to 2 in firefox. If so, could you retry with a value of 1 (I believe you have to restart FF after changing this configuration)?

Thanks for all the tips thus far. It's been very instructive!

PS: enter about:config in the address bar in firefox to see and change the options mentioned above

[Phillip Bunch]

Hey Doug,



A few questions as I'm trying to get a grasp on color profiles:

What do you have gfx.color_management.mode set to in firefox?

Also, do you have a profile assigned to gfx.color_management.display_profile?

What version of firefox do you use and are you on a wide gamut monitor?



My hunch is that you are on a wide gamut monitor and your gfx.color_management.mode is set to 2 in firefox. If so, could you retry with a value of 1 (I believe you have to restart FF after changing this configuration)?



Thanks for all the tips thus far. It's been very instructive!



PS: enter about:config in the address bar in firefox to see and change the options mentioned above

Hey Doug,







A few questions as I'm trying to get a grasp on color profiles:



What do you have gfx.color_management.mode set to in firefox?



Also, do you have a profile assigned to gfx.color_management.display_profile?



What version of firefox do you use and are you on a wide gamut monitor?







My hunch is that you are on a wide gamut monitor and your gfx.color_management.mode is set to 2 in firefox. If so, could you retry with a value of 1 (I believe you have to restart FF after changing this configuration)?







Thanks for all the tips thus far. It's been very instructive!







PS: enter about:config in the address bar in firefox to see and change the options mentioned above

Very interesting and informative (and yet somewhat stressful) thread! With the usual misgivings, I decided to attempt to contribute to the discussion, as follows:

First, I suggest that another Firefox parameter, also used in Photoshop CS5, that may be relevant is: gfx.color_management.rendering_intent

By default, my Firefox version 6.0.2 is set to "perceptual" rendering intent.

However, I'm not sure this is what I want for Firefox since I have attempted to follow Martin Evening's advice in his excellent book "Adobe Photoshop CS5 for Photographers", pages 647ff, 661ff, and especially page 670. This detailed yet readable (IMO) book recommends that one should usually avoid using "perceptual" rendering intent; instead one should use "relative colorimetric" as one's rendering intent, if I'm following all this correctly (hardly guaranteed). The reasoning behind this recommendation is as follows, excerpting from page 670:

"Which rendering intent is best? If you are converting photographic images from one color space to another, then you should mostly use the Relative Colorimetric or Perceptual rendering intents. Relative Colorimetric has always been the default Photoshop rendering intent and is still the best choice for most image conversions. However, if you are converting an image where it is important to preserve the shadow colors, then Perceptual will often work out better."

Also consider this from page 670:

"Perceptual rendering provides a best guess method for converting out-of-gamut colors where it is important to preserve tonal separation (such as in the shadow detail areas), but it is less suitable for images that happen to have fewer out-of-gamut colors."

And from page 671:

"Relative Colorimetric is the default rendering intent utilized in the Photoshop color color settings. Relative Colorimetric rendering maps the colors that are out of gamut in the source color space (relative to the target space) to the nearest 'in-gamut' equivalent in the target space."

Thus, an issue: if people are using the default Photoshop option of "relative colorimetric" rendering intent, shouldn't we set our Firefox browsers to also use this rendering intent instead of the Firefox default "Perceptual" rendering intent?

Another issue: does rendering intent matter in the context of viewing web images, and if so, for which images, and by how much and in what ways? I've personally had the most trouble re out-of-gamut colors when photographing light-purple or lilac flowers. I think we need some good, stress-case but realistic test images, preferably from real photos. Synthetic test patterns are also available, and probably have a role, too, if we can find some suitable examples.

FYI, here are some links to some Firefox color management parameters:

http://kb.mozillazine.org/Gfx.color_management.enabled - one MUST have color management enabled, I assume, to view photos usefully.

and

http://kb.mozillazine.org/Gfx.color_...ndering_intent

Here's a link to a convenient, user-friendly, easy-to-install add-on for Firefox to view and/or to reset one'e Firefox browser color management parameters:

https://addons.mozilla.org/en-US/fir...or-management/

I personally use this add-on and believe it is much easier to use than messing with Firefox's "about:config" parameters, especially for non-technical people.

I hope this post is useful or at least not a distraction! I also hope I've caught all my grammar and syntax errors, etc!

--------------------------------------

The world's shortest book review: I find the above book by Martin Evening provides a great balance of completeness, readability, and practicality, while avoiding overwhelming the non-expert user. Trying to piece a topic like color management together from web and other resources is very difficult IMO, but with Evening's book one can generally at least try to wade through forum issues, etc. He has very specific, explicit, detailed recommendations for CS5's Color Settings parameters, etc. I also find it's a great general-purpose reference book for Photoshop CS5.

[Phillip Bunch]

Hey Doug,

A few questions as I'm trying to get a grasp on color profiles:
What do you have gfx.color_management.mode set to in firefox?
Also, do you have a profile assigned to gfx.color_management.display_profile?
What version of firefox do you use and are you on a wide gamut monitor?

My hunch is that you are on a wide gamut monitor and your gfx.color_management.mode is set to 2 in firefox. If so, could you retry with a value of 1 (I believe you have to restart FF after changing this configuration)?

Thanks for all the tips thus far. It's been very instructive!

PS: enter about:config in the address bar in firefox to see and change the options mentioned above

Very interesting and informative (and yet somewhat stressful) thread! With the usual misgivings, I decided to attempt to contribute to the discussion, as follows:

First, I suggest that another Firefox parameter, also used in Photoshop CS5, that may be relevant is: gfx.color_management.rendering_intent

By default, my Firefox version 6.0.2 is set to "perceptual" rendering intent.

However, I'm not sure this is what I want for Firefox since I have attempted to follow Martin Evening's advice in his excellent book "Adobe Photoshop CS5 for Photographers", pages 647ff, 661ff, and especially page 670. This detailed yet readable (IMO) book recommends that one should usually avoid using "perceptual" rendering intent; instead one should use "relative colorimetric" as one's rendering intent, if I'm following all this correctly (hardly guaranteed). The reasoning behind this recommendation is as follows, excerpting from page 670:

"Which rendering intent is best? If you are converting photographic images from one color space to another, then you should mostly use the Relative Colorimetric or Perceptual rendering intents. Relative Colorimetric has always been the default Photoshop rendering intent and is still the best choice for most image conversions. However, if you are converting an image where it is important to preserve the shadow colors, then Perceptual will often work out better."

However, consider this from page 670:

"Perceptual rendering provides a best guess method for converting out-of-gamut colors where it is important to preserve tonal separation (such as in the shadow detail areas), but it is less suitable for images that happen to have fewer out-of-gamut colors."

And from page 671:

"Relative Colorimetric is the default rendering intent utilized in the Photoshop color color settings. Relative Colorimetric rendering maps the colors that are out of gamut in the source color space (relative to the target space) to the nearest 'in-gamut' equivalent in the target space."

Thus, an issue: if people are using the default Photoshop option of "relative colorimentric" rendering intent, shouldn't we set our Firefox browsers to also use this rendering intent instead of Perceptual?

Another issue: does rendering intent matter in the context of viewing web images, and if so, for which images, and by how much and in what ways? I've personally had the most trouble re out-of-gamut colors when photographing light-purple or lilac flowers.

FYI, here are some links to some Firefox color management parameters:

http://kb.mozillazine.org/Gfx.color_management.enabled - one MUST have color management enabled, I assume, to view photos usefully.

and

http://kb.mozillazine.org/Gfx.color_...ndering_intent

Here's a link to a convenient, user-friendly, easy-to-install add-on for Firefox to view and/or to reset one'e Firefox browser color management parameters:

https://addons.mozilla.org/en-US/fir...or-management/

I personally use this add-on and believe it is much easier to use than messing with Firefox's "about:config" parameters, especially for non-technical people.

I hope this post is useful or at least not a distraction! I also hope I've caught all my grammar and syntax errors, etc!
--------------------------------------

The world's shortest book review: I find the above book by Martin Evening provides a great balance of completeness, readability, and practicality, while avoiding overwhelming the non-expert user. Trying to piece a topic like color management together from web and other resources is very difficult IMO, but with Evening's book one can generally at least try to wade through forum issues, etc. He has very specific, explicit, detailed recommendations for CS5's Color Settings parameters, etc. I also find it's a great general-purpose reference book for Photoshop CS5.

[Sidharth Kodikal]

Phillip, many thanks for the additional info. I will experiment with the parameter you mentioned and will definitely get the book you recommend - sounds very thorough.