What do I do with color profiles

#1

Hi,

I am just beginning to inform myself about color profiles. From what I understood, there can be 3 different color profiles in the icc format, that play their role:

  1. I got an ICC profile after I would have calibrated my monitor. This ICC I would set normally in gnome’s color settings, right?

  2. Second I should “work” with a color profile (in my programs such like gimp) like AdobeRGB1998 to be sure to work in a standard color profile; is this correct?

2a. But, Question, why not using my Calibrated-Monitor-ICC in gimp?

  1. And third, for what is a printing ICC profile (such as an icc file I could download from a printing service). Is this just used (also) in my editing software like gimp or darktable, just for doing this thing called “Softproof”?

What color profile would I give “with” the jpg file when giving it to a print service? The AdobeRGB1998 one or that one of the printing service?

What color profile would you normally include in lets say a wedding photography, knowing that the couple will print the photos on some printing service?

Sorry for perhaps asking such newbie questions, but for me these are really basic question I never thought about.

Very kind regards

Pragomer

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(Glenn Butcher) #2

@pragomer, you are teetering at the brink of the rabbit hole that is color management. Beeing a recent teeter-er myself, I can tell you that it will be challenging, but rewarding.

That said, to put a good perspective on your immediate questions, I think it’ll help to realize that profiles in color management are less about doing something to an image and more about describing its characteristics. In that regard, a ‘profile’ contains two critical pieces of information: 1) the range of colors the image captures, and 2) how far from the original linear light relationship has the image been scaled.

So, when your camera captures an image, there’s a profile associated with it that’s unique to the camera’s capabilities to define color. You can make such a profile yourself with a color target and some software, but for the time being it’s good to rely on the internal profiles the raw processors contain for each camera they support.

When a raw processor shows you the result of opening your raw file, it usually has converted the image from the camera characteristics to some “working profile”. That’s the place where your reference to AdobeRGB1998 is about. There are a variety of such profiles; some raw processors let you pick one, others hard-code it to a specific one. The important point about working profiles is that they allow a large color range to preserve the colors during your editing.

And then, when you go to output your image for regarding, a last conversion is required for the intended medium. That includes both display and printing, and each medium should have a specific profile aligned to its capabilities to render color and tone.

The key thing to keep in mind in all this is that a color profile really is metadata about the image that is used to consider and manage its color from capture to output.

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(Glenn Butcher) #3

Now, your specific questions:

Yes, and that activity makes the display profile available for all the software that properly manages color for output to the display. Just because you inform gnome about the profile doesn’t mean all the software will use it. So, make sure you go to your program’s color management settings and make sure it knows to look for the display profile in the proper place.

Yes, although I’d try to pick a “larger” profile like ProPhoto or Rec2020.

Output devices, while getting better, generally have smaller gamut (color range) than the working profiles. So you don’t want to work your image in the display profile.

The printing profile should be a concise description of the printing machine’s color capabilities. “Softproofing” is the act of using that profile to pre-visualize what the colors will print, before you go through the expense and effort of putting ink to paper.

In any event, you want the output JPEG, TIFF, PNG, whatever, to contain an embedded profile that describes its color. A good print service will be able to use such an image to convert to their printer profile to print the image. However, a lot will tell you to just make the image sRGB or some other gamut; if they say that, they might just print your image without any color consideration, assuming you did the conversion and their printer aligns to sRGB.

Again, the best first thing to do is to deliver the image with an embedded profile that describes its gamut. That said, sRGB is considered, for the time being, as a ‘least common denominator’ color space, as a lot of monitors approximate its capability. That’s changing now, as high-gamut monitors become mainstream…

Hope this helps…

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#4

Hi @pragomer,

@ggbutcher is too modest when he calls profiles rabbit holes.
They are not. They are a combination of an abyss, a quagmire, and a jungle,
with a can of worms admixed.

Rawpedia seems to be down, presently, but that is a good start: http://rawpedia.rawtherapee.com/

Then you will find lots of good information here: https://ninedegreesbelow.com/

And a short explanation of different (printing) gamuts:

Don’t forget to search the forum. Use search words such as gamut, profile, et cetera.

Have fun!
Claes in Lund, Sweden

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(Hermann-Josef) #5

@pragomer

at least in Germany almost all printing services do not process embedded ICC-profiles. They just assume, everything is in sRGB. So if you render the output to sRGB colour space you are on the safe side.

To my experience, in order to understand colour management it is mandatory to study not only one but several books – at least in part. A good starting place is “Real world color management” by Bruce Fraser, Chris Murphy and Fred Bunting (2nd edition 2005). Somewhat old but still very helpful to understand the basic principles. Unfortunately it is out of print but you can buy used copies at Amazon.

Hermann-Josef

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#6

Hey Guys,

I really must say, this community is so so great. I never thought people could be so patient helping each other. I am a 12year Linuxuser now and forums like the ubuntu community, etc. were always great, but you guys are really so so kind and helpful. Thank you so much.

I will now test a little bit with icc profiles.

Kind regards
Pragomer

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#7

Mm, perhaps a simple (I hope its simple) A-or-B question: :blush:

What profile would you generally work in : sRGB or AdobeRGB?
As far as I read, Adobe is the little more “wider” colorspace, but with sRGB I would be more on the “safe side”. Is this correct so far?

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(Mica) #8

If you generally just post your work to the web, sRGB is what you want. If you print, you’re probably better off with AdobeRBG.

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#9

The goal is mostly, that my wife does wedding and newborn photos. So I would think, her customers will often print their photos via a printing service. So, in this case AdobeRGB would be the better choice.

But, my wife also puts her photos to her website, so what would you work with, knowing that you will need both: printing and web? Could I or should I choose one? For example working with Adobe because of printing, and then, before publishing to the web, convert to srgb and “check” visually if everthing is ca. in the right place. Would this be correct?

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(Mica) #10

You can not have more than one per image, but you can have one file for the website and one for print.

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(Hermann-Josef) #11

@paperdigits

If you print, you’re probably better off with AdobeRBG.

As I said above, this only is true, if monitor / printing service / printer are capable of dealing with AdobeRGB. Otherwise you are sort of “flying in the dark”.

Hermann-Josef

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(Glenn Butcher) #12

I “work” (edit) in Rec2020, and save to sRGB.

I don’t believe AdobeRGB is big enough to work in, and I don’t do any display or printing that would take advantage of it.

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#13

Two more questions, please. I was reading GIMP docs and noticed the following statement:

https://docs.gimp.org/2.10/en/gimp-imaging-color-management.html

I usually export images from RT to GIMP as a tiff. I have made a monitor profile (almost exact match to sRGB) and from GIMP I export jpegs for web, so sRGB is a fine final image profile.

Questions:

  1. What is the best output profile for the tiff from RT when I am going to process the image in GIMP before the final export as jpeg for web? So far I have been using RTv4_sRGB and have not allowed GIMP to do the conversion.

  2. What if I bought a wide gamut monitor and wanted to print images in AdobeRGB, are there some issues with GIMP that it cannot handle properly wider color spaces (both working and output)?

Thanks in advance!

EDIT: According to this 6 month old post by Elle Stone, one should stick to sRGB with GIMP 2.10

https://ninedegreesbelow.com/photography/patched-gimp-compared-to-default-gimp.html

Seems to answer to the second question about wider color spaces if it is still correct information.

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#14

There isn’t a simple answer. What I do know is that the GIMP devs are hard at work in transitioning their tools to handle more types of bit depths, colour gamuts and TRCs. Working in sRGB is fine. However, there are many sRGB profiles, including RTv4_sRGB and GIMP’s builtin. I would just stick with the one that comes with the input file. Converting from one sRGB to another sRGB doesn’t do all that much, unless this sort of stuff bothers you.

There are cases where you would want to start or convert your image into a larger gamut and / or give it a linear TRC; e.g., fixing the colour balance, according to one of Elle’s articles. But then you will have to worry about resolving out of gamut or range issues every step of the way, esp. when you have to do your final colour space conversion.

Without going into further detail, I suggest you follow some of her tutorials. But keep in mind that many of them are older than the current version of GIMP, so not everything would apply. When in doubt, give her an email “ellestone (at) ninedegreesbelow (dot) com”.

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