Colour Management Problem with Firefox

[Round Tuit]

You can do a Firefox refresh, which preserves all your favourites.... it will reset everything else to default.

I'll try that later on. Thanks

[xpatUSA]

Dan, André,

Do you both have an app that can display all image file meta-data such that any embedded profile is displayed?

I ask because earlier there seemed to be some doubt as to whether a profile was embedded or not - Perhaps I misunderstood.

[pschlute]

Bingo, as we say this side of the pond.

Thanks for the suggestion. That was indeed the issue. Smugmug must display only in sRGB. Following your suggestion, I dragged the two images I exported yesterday into new tabs in Firefox. They look different, just as they do in Photoshop.

Good. That shows your workflow is correct and so are your Firefox settings.

I did a google and found some old posts about Smugmug only displaying in sRGB. Flickr, who are now owned by Smugmug have no such limitation. A similar issue would arise if I were to post the two images to Facebook. FB strips the colour profile and replaces it with one of their own, and the two images would look identical. You could try downloading the images from Smugmug, and open them in Photoshop to see what the profile is.

[xpatUSA]

Here is a picture of what I see in firefox. The window on the left is the ProPhoto tagged image and the one on the right is sRGB

Thanks for that. In my FireFox, Win7, sRGB monitor they look similar but not the same, for what that is worth. My screen color picker shows:

Left: red 255,0,31 green 0,245, 38
Right: red 247,0,38 green 96,241,73

My brain is hurting but gamut-clipping springs to mind.

Not intended as a further contribution but I ran the RYGB images that I posted earlier around my system/apps today and learned that color management is highly variable on my machine ...

Desktop icons: PP w/icc and PP no/icc both dull.
FastStone: one dull, one not.
FireFox: both not dull.

Above is FYI. Not looking for advice about those findings, so as not to divert the thread.

I have an app that can show a 3D gamut. I opened up my RYGB image and compared it with sRGB and ProPhoto gamuts in LAB space.

In sRGB the image primaries were where they should be - on the edge of the sRGB boundary.

In ProPhoto the image primaries were again where they should be - inside the boundary.

But it was noticeable that the blues were almost in the same LAB position, thereby telling me why the blue appearance in yall's image renderings doesn't change much.

[Round Tuit]

I have reset Firefox and the problem persists. The only thing that I can think of that might help is reinstalling Windows and I am not going to do that.
Thank you Peter, Dan and Ted for your help. It is appreciated.

[xpatUSA]

Could you do an experiment for me. Create a new image in prophoto space with a pure red, a pure green and a pure blue squares. Duplicate it and convert the duplicate to sRGB space. Save both as tagged jpeg and open both in Firefox. The blue squares should look the same but the red and green ones should be visibly more saturated in the prophoto version.

I don't think you can go from e.g. red 255,0,0 in ProPhoto to sRGB because that gets you 348,-131,-26 in sRGB according to Bruce Lindbloom's calculator, all out-of-bounds. I can imagine those getting clipped by whatever receives them and I can imagine red being different because of that clipping.

http://www.brucelindbloom.com/index....alculator.html

You can however go from 255,0,0 in sRGB to ProPhoto which gets you 179,70,26 image data values. Works in Bruce's calculator and also in Irfan's hex view.

With a PP profile embedded, any device (even an Eizo LOL) should display pure red to the eye, i.e. xy = 0.64,0.33 (D65), from those image data values.

May I suggest we all test the other way around. In sRGB working space, create a small red box. Save. Re-open still in sRGB working space but save as ProPhoto. Suggest TIFFs to avoid obfuscation by JPEG not that it should make a huge difference.

Mine are here:

http://kronometric.org/phot/post/CiC...B-assigned.tif

http://kronometric.org/phot/post/CiC...d%20to--PP.tif

Right click to download (I think).

[DanK]

Andre,

did you try the things I tried? In particular, did you try other browsers to see if they behave the same way? And if so, did you try dragging the saved JPEGs directly into browser tabs rather than viewing on another site? In my case, the first clue is that all 4 browsers I tried behaved exactly the same (wrong) way. Then, following Peter's suggestion of dragging directly into the browser showed that the issue wasn't browsers, but the site I was viewing (Smugmug).

Dan

[pschlute]

I don't think you can go from e.g. red 255,0,0 in ProPhoto to sRGB because that gets you 348,-131,-26 in sRGB according to Bruce Lindbloom's calculator, all out-of-bounds. I can imagine those getting clipped by whatever receives them and I can imagine red being different because of that clipping.

But when you start with a ProPhoto 255 red and convert the image you should end up with a 255 red in sRGB.

The two colours will not look the same because they are not.

[xpatUSA]

But when you start with a ProPhoto 255 red and convert the image you should end up with a 255 red in sRGB.

A bit vague, sorry. You appear to be forgetting how embedded profiles work.

The two colours will not look the same because they are not.

Again, a bit vague, sorry.

The CIE color x=.64, y = .33 Y = 0.212673 at D65 is the same color no matter what produces it.

Go to Bruce's calculator enter all those and see what RGB values you get when set to sRGB and D65.

Then change sRGB to ProPhoto and see what RGB values you get ... they are quite different, right?

In other words, RGB values do not tell us what color something is, not even 255,0,0 for example.

[pschlute]

Uploaded the JPEGs for what they're worth:

Ted, both those jpegs are in RTv4_sRGB colour space.

[xpatUSA]

Ted, both those jpegs are in RTv4_sRGB colour space.

Good point!

Yes, I saved The TIFFs from RawTherapee, but didn't change the output profile, duh.

As I struggle to clarify stuff with an addition, I'll often screw things up in my haste. Fortunately, the TIFFs still tell the tale until proven otherwise.

I'll go back and delete the JPEGs leaving only the TIFFs for discussion.

Thanks for the heads-up!

[pschlute]

Ted, only one of the tiffs has a colour profile.

[pschlute]

I have reset Firefox and the problem persists. The only thing that I can think of that might help is reinstalling Windows and I am not going to do that.
Thank you Peter, Dan and Ted for your help. It is appreciated.

Andre, can you post or link to the two images ?

[xpatUSA]

Ted, only one of the tiffs has a colour profile.

Sorry fixed in the subject post.

Image data values should not have changed because it was assigned, not converted.

Thanks for checking my stuff!

[xpatUSA]

Meanwhile, illustrating differences in image RGB values for the same CIE color:

sRGB:


ProPhoto:


Posted because Bruce's calculator takes some getting used to. I hope that the differences are clear enough and that it is agreed that different RGB values do not necessarily mean a different real color.

[pschlute]

I hope that the differences are clear enough and that it is agreed that different RGB values do not necessarily mean a different real color.

Agreed. But Andre's problem is that a ProPhoto image of the extreme R and G , when "converted to sRGB" displays identically to the original Prohoto image, when viewed in a colour managed browser on a wide gamut screen.

That should not be happening.

[xpatUSA]

Agreed. But Andre's problem is that a ProPhoto image of the extreme R and G , when "converted to sRGB" displays identically to the original Prohoto image, when viewed in a colour managed browser on a wide gamut screen.

That should not be happening.

I guess my understanding is hampered by:

a) not really knowing what a "ProPhoto image of the extreme R and G" is and

b) not owning a wide-gamut monitor

Any way I could make a ProPhoto image of just the extreme R and G so as to see what's inside it?

Or has one such already been posted in this thread?

[pschlute]

I guess my understanding is hampered by:

a) not really knowing what a "ProPhoto image of the extreme R and G" is and

b) not owning a wide-gamut monitor

Any way I could make a ProPhoto image of just the extreme R and G so as to see what's inside it?

Or has one such already been posted in this thread?

It is an image of a 255 red and green in ProPhoto colour space. I think I have said this a number of times now.

I showed a phone capture of my screen in post 24.

give me a minute and I will post the actual images.

[pschlute]

Here is an image in ProPhoto colour space.

[IMG]Untitled-1 by Peter Schluter, on Flickr[/IMG]

[pschlute]

Here is the same image, but CONVERTED to sRGB colour space
[IMG]Untitled-2 by Peter Schluter, on Flickr[/IMG]