Color modes WILL drive me crazy some day...

[AJLynn]

So I was doing some shooting to try out my new lens on my Nikon D60 (the 35mm AF-S DX - it's pretty sweet) but ran into a whole big stinking pile of color profiling. I posted here: http://photo.net/nikon-camera-forum/00Sm7q but I bet the people on this forum can help.

 

Essentially since I was just doing some casual shooting I used JPG. I have a custom Optimize Image config that involves color mode IIIa, + Saturation and Auto Tone Compensation (basically a custom Vivid mode that suits my taste in colors). When I posted to the site, my colors came out wrong - as if my use of IIIa (which is sRGB but the camera makes it more vivid) had been forgotten and I had been using regular sRGB (Ia).

 

This problem was Firefox-only; Safari handled the colors as expected. I tried using Gmail to mail the photos to myself and still be viewing them in Firefox, and the problem repeated.

 

When I followed the link that the other guy posted and changed my Firefox config to allow color management, then restarted Firefox, and voila, the colors were good. So I guess using IIIa adds a color profile to the image to handle the color changes, which is only usable by software that supports color management (and Firefox users can't be expected to support color management, and don't let's get started on IE).

 

So is it possible to get Photoshop to correctly convert the colors to whatever standard sRGB Firefox expects? Surely it must be - it can display the image correctly on an sRGB monitor after all - but trying to convert to sRGB does nothing because it already is sRGB, and using Save For Web spits out the image without the color profile so it looks equally bad in all software. And I know I need to calibrate my monitors, but that's not the problem.

[Dave Buchhofer]

I got the 35f1.8 myself the other day for my d90, and it is damn sexy.. I think its shelved my 18-105 until summertime easily.

 

As to the profiling, I could have sworn you can do it via the save for web, it will strip out all of the color profiling (and if you want, the exif data.)

 

Otherwise i think you do a ConvertToProfile, AdobeRGB, and then an assign dont color manage?

[Matt McDonald]

You can't do edit - convert to profile using relative colormetric and convert it to plain jane sRGB?

[AJLynn]

I don't want to strip the profile, I want to burn it in. Take this photo for example. With correct color the brick is a deep red and the mulch is the same; in Save For Web it's the dull brown-orange that I guess it really did look like in the boring light (but I don't want what it really looked like, I want my jacked up colors).

 

BTW do you notice a magenta-green CA on sharp contrast lines?

[AJLynn]

You can't do edit - convert to profile using relative colormetric and convert it to plain jane sRGB?

 

I'm looking at that window now; the thing is, it's already in "sRGB IEC61966-2.1" (and AFAIK that is as plain a jane as I've got).

[Dave Buchhofer]

Yea its noticeable, but not that bad.. you shooting raw? that is a pretty harsh condition though, shooting backlit thin dark lines.

 

I tend to do RAW+JPG, and go with parts of both for shots i really like, and jpg for the basics. I think the d90 corrects for a lot of the CA.

 

so far I'm mostly in the 'shooting toddlers' category though.

[AJLynn]

I shot these in JPG because I didn't want large RAW files when I'm just messing around; and in theory doing so should keep my colors the way I want them since I don't need to run them through another RAW processor.

 

This crap makes me want to shoot more film.

[Scott Erstad]

Have you tried "convert to profile" in photoshop before saving out?

Edit/convert to profile.

 

hope this helps- Scott

[Matt McDonald]

The JPG you linked to is the original right? Not the "save for web"?

 

I opened it in Photoshop did "save for web" with no profile attached then opened both in firefox and they look the same.

 

Did you check your results on another computer?

 

I've only looked into browser color management lightly but I thought that you needed color management only when using profiles other than sRGB.

[Dave Buchhofer]

It depends, i believe firefox enabled color management in the 3.1 update (AS a default), so it may depend on your versions also.

[AJLynn]

The JPG you linked to is the original right? Not the "save for web"?

 

I opened it in Photoshop did "save for web" with no profile attached then opened both in firefox and they look the same.

 

Did you check your results on another computer?

 

I've only looked into browser color management lightly but I thought that you needed color management only when using profiles other than sRGB.

 

Huh. I tried this in Windows and got the same result you did. Maybe this is actually a Mac/Windows issue. Which would be even worse - these will look completely different on different computers.

 

I think I need to calibrate everything then never post to a web site again.

[Matt McDonald]

There's that Mac vs. PC gamma thing. Which I thought was done with OSX. Maybe not?

[AJLynn]

Evidently there are built in compensations in OSX - which are not on by default in Firefox.

[AJLynn]

Anybody have a favorite under-$200 color calibration thingy for Mac and Windows?

[Matt McDonald]

We use an Eye-One display made by xRite. I like it.

 

There is a company called Chromix that sells and performs a lot of color management stuff. Their prices are good, often with open box specials and I have always felt that they are very helpful on the phone. They could probably get you setup as well as anyone.

[Jeff Mottle]

My favorite subject matter color management.

 

When you do not shoot RAW with your camera, your photos will always be tagged with a profile from a Nikon DSLR. The options are usually sRGB and AdobeRGB. Which one you select generally depends on the color of the subject matter you are shooting, and your workflow. If you work in a color managed environment and have access to Photoshop, I'd personally want to have the camera tag the images with AdobeRGB. Doing this will ensure your images have the largest gamut of colors to work with. sRGB is a smaller color space than AdobeRGB, so assigning sRGB at the camera level will automatically clip most of the colors the camera saw.

 

RGB values by their very nature are ambiguous and have no "scale" attached to them. Assigning a profile to them provided that scale, by mapping the RGB values into a known and quantifiable 3 dimensional color space. It's very much like putting a point into CAD without having a 3D coordinate system and having someone ask you how close to the origin the point is. Without the coordinate system, there is no way you could tell. A profile allows the RGB values coming from the camera to be understood by many devices as the same thing and is correlated to how our eyes actually see color. (I'll cover a lot more about this in Brian's new book)

 

Ok, enough theory and on to the problem. As I mentioned above images without a profile are simply RGB values without a scale, or more specifically only a scale that is understood by that specific camera. (device-dependant color space) So if you view that image without a profile, by stripping it, or in an environment that does not understand profiles, the display you are viewing it on is going to take those RGB values in the image and interpret them as they know how. On a mac it uses your default monitor profile and on a PC is uses sRGB. On the latter, windows does not read your profile, but rather assumes your image is in sRGB color space. sRGB is a synthetic colorspace based on the average gamut of a CRT display.

 

Now, you are probably wondering why then if windows assumes an sRGB colorspace on all images, your image does not look the same in PhotoShop (a color managed environment) as it does outside of PhotoShop (firefox etc), a non-color managed environment. I'm guessing you are using a display that might be a wide gamut display or a display who's gamut exceeds that of the sRGB color space. This is why you are seeing a huge difference and Matt (designmule) did not. I'm guessing he is using a display that has a gamut that is closer in gamut to sRGB.

 

So how does a display factor into this? If you remember, a profile assigns a scale. All of the RGB values in that image are mapped to that scale (color space). Depending upon the scale, the most saturated RGB numbers could have a different meaning. Color spaces all relate to how we see color and fit within the gamut of colors we can see. sRGB is smaller than aRGB, but both fit into the gamut of colors we can see, so the same RGB values can have a different meanings. When you work in a color managed environment the monitor profile and the image profile work together to display the image RGB values in a consistent way. (There is more to this, but I'll not get into that here). When you work outside of a color managed environment the monitor profile is ignored, so your sRGB data ends up being scaled to the gamut of the display. When your display's gamut closely resembles the sRGB colorspace, the image looks very similar in both color managed and non-color managed environments. However when you use a wide gamut display or a display that can display colors larger than the sRGB color space, the image's sRGB profile is being stretched to match the gamut of the display. In the case of a wide gamut display that has a color space that is very close to AdobeRGB, so your sRGB data is essentially being interpreted as such. You would get the same result as opening your sRGB tagged image in PhotoShop and ASSIGNING the image an AdobeRGB profile.

 

If you look at the following image, you can see how the sRGB colorspace relates to the AdobeRGB color space. The horseshoe shaped diagram represents the entire range of wavelength of color we can see. Let's assume we are looking at the greenest RGB values in your image. If you assign the sRGB color space as your scale, you could look at the top point of the triangle. If you assign AdobeRGB as the scale, you can see how much more saturated those same RGB values are being interpreted as. That is why you see color shift in your images. Your display would likely be represented by a triangle that falls somewhere between sRGB and AdobeRGB or very close to AdobeRGB. As an aside the points of these triangles represent the most saturated colors each color space is capable displaying for each primary. Red, Green and Blue.

 

 

 

So now you know why it is happening, what is the solution?

 

As you discovered most browsers are not color managed. The only ones that are include Safari on the mac, Omniweb on the mac and firefox on the PC or Mac if you enable color management via the config menu or with a 3rd party plugin.

 

Displays that are capable of displaying gamuts larger than sRGB (especially wide gamut displays) are VERY problematic when it comes to viewing images outside of a color managed environment. It's a well documented problem as causes a great deal of confusion.

 

Unfortunately there is no solution for this other than to use an sRGB gamut display, work only in a color managed environment, or use a high end display that allows you to force the gamut of the display into an sRGB color space. There is a workaround solution I've worked out that is about as good as you can get. This will essentially change the RGB color numbers in the source image so that the image looks ok when those RGB values are mapped to a wide gamut display outside of a color managed environment. This solution is not perfect and has its limitations.

First in Photoshop go to Edit -> Color Settings and under Settings set the drop down to North America Prepress 2. This will set up all of the other color management settings to how they should be. I won't go into them here as that's another chapter for a book

 

With these settings when you open an image that has an sRGB profile assigned you will be prompted to take an action. Normally I would Convert the colors to the working space, but for the purposes of this demonstration, select "use the selected profile (instead of the working space)". Your image has now been opened and is using the sRGB profile to display the colors and you will edit the colors in the sRGB color space.

 

Go to Edit -> Convert to Profile ->AdobeRGB and press OK.

 

Now save this image and ensure that the ICC profile checkbox is assigned. (It will say AdobeRGB).

 

What we have done is to change the color numbers of the image so that when they are viewed in the AdobeRGB colorspace or on a wide gamut display, they look the same as the original sRGB image you shot.

 

The following will now happen:

 

1. If you view this image outside of a color managed environment on a wide gamut display it will look right.

2. If you view this image in a color managed environment it it will look good as it will read the assigned AdobeRGB profile.

3. If you view the image on a display with a gamut similar to sRGB in a non-color managed environment, the colors will shift (probably more desaturated), but not as severely. You can't have your cake and eat it too.

 

If your display is not a wide gamut display, but is capable of displaying a gamut larger than sRGB, then you will still see a shift, but again, not as much or as severe. Overall, this is not a great solution, but it's about as close as you can get. Try it out and see what kind of millage you get.

 

Hopefully this helps.

Edited March 22, 2009 by Jeff Mottle

[Brian Smith]

yeah...what jeff said

[AJLynn]

Wow, thanks Jeff. Now I take it that if I were to shoot raw and use calibrated monitors this would simplify things? Also, do SPVA LCDs such as my Macbook Pro and my Dell Ultrasharp 2001 qualify as "gamut larger than sRGB"? I'm assuming that by "wide gamut" you mean the pro level displays that are marketed by how much of the Adobe RGB space they handle.

[Crazy Homeless Guy]

BTW do you notice a magenta-green CA on sharp contrast lines?

 

This is bad. Did you try other lenses before buying that one?

[AJLynn]

This is bad. Did you try other lenses before buying that one?

 

Yeah and they all do it to some extent; I've seen worse. If I had a more expensive camera it would have onboard correction, and this is a cheap lens after all. Here's my worst example at 100% crop. The shiny bits are mirrored and reflecting bright slightly overcast sky.

 

The only lens alternative that's really an alternative to this one (a normal prime on DX with built in AF motor) is the Sigma 30mm that costs twice as much.

[Jeff Mottle]

Now I take it that if I were to shoot raw and use calibrated monitors this would simplify things?

 

No RAW by itself does not have a colorspace as RAW data is the "RAW" sensor data from the camera. You need a RAW translator to convert that data into an RGB format, at which point a colorspace is assigned. The advantage, aside from having considerable more flexibilty in editing the images, is that you have access to everything the camera saw. When that data is converted to an RGB format you can map it to a much larger colorspace like ProPhotoRGB. Right now you'd still end up converting it into a smaller space for printing and on screen viewing, but one day all devices will be able to display much larger gamuts, so you have somewhat future-proofed your images by not throwing away all that color data.

 

Also, do SPVA LCDs such as my Macbook Pro and my Dell Ultrasharp 2001 qualify as "gamut larger than sRGB"? I'm assuming that by "wide gamut" you mean the pro level displays that are marketed by how much of the Adobe RGB space they handle.

 

I'm not familiar with the Ultrasharp 2001, so I don't know its specs. If you can find them I can take a look. The gamut of your macbook pro depends on the generation. Older versions had around 45% of the NTSC gamut, which is similar to AdobeRGB but smaller and bigger in different locations. The latest generation of the MBP display is about 72% of NTSC. I have a the generation of MBP one behind the current and its gamut is smaller than sRGB (which is pretty pathetic considering most people would want to do graphic on them). The new generation would be a bit bigger I think, but I'd have to see the ICC profile to take a look to know for sure.

 

Wide gamut displays are generally those that market themselves as being at least 100% of the NTSC gamut. Dell, Eizo, NEC all have wide gamut displays. I'm sure there are others out there now too.

 

 

If you can profile your displays and send me the ICC profiles I can show you what is going on with your situation. Color shift in a non color managed environment can happen any time the gamut of the display differs from sRGB, whether it's bigger or smaller. Although generally the colors become more saturated when the display gamut is larger. Remember sRGB is only an approximation of the average CRT gamut. Not every display is the same and very few actually are idential to the sRGB specification, but it's the industries best attempt at some form of standardization. As wide gamut displays become more common, this spec will have to be increased. Maybe they will adopt AdobeRGB.

Edited March 17, 2009 by Jeff Mottle

[AJLynn]

Thanks again. I think I'm going to invest in a calibration device to help deal with this. Or just shoot film on my SRT

 

The MBP is first generation 17" (before they went glossy). Those new ones look amazing, though I think the best color I've seen so far on a non-CRT screen is my SXRD TV. I'll try calibrating that hooked up to the MBP and see what my photos look like then.

[Jeff Mottle]

BTW, did my explanation of the problem make sense. As I'm writting part of the chapter for Brian's new book on this problem, I wanted to be sure my explanation was clear. It's easier to understand with some more background info into the theory that I'm explaining in the book, but I am curious to know if this explanation as is, was clear.

[AJLynn]

I think it was pretty clear but the book had better be for an advanced audience (e.g., people who know a lot of computer graphics but just aren't experienced in this particular area). Also I doubt I'd be manually correcting colors like that for anything but a pretty important web site; more likely I'd be running raw through Aperture, using curves and converting to sRGB.

[Jeff Mottle]

I think it was pretty clear but the book had better be for an advanced audience (e.g., people who know a lot of computer graphics but just aren't experienced in this particular area). Also I doubt I'd be manually correcting colors like that for anything but a pretty important web site; more likely I'd be running raw through Aperture, using curves and converting to sRGB.

 

Cool. Yes the new book is "Advanced Expert".

 

I'm covering this in my chapter, but Color Management and Color Correction are two seperate subjects. Color Management is about a pipleline that facilitates achiving similar color across all devices. Color correction is the act of adjusting an image to achive a more artistically pleasing image.