How to generate 16 bit linear, gamma=1, output files?

My current preferred ICC profile dumper is “iccDumpProfile.exe”. It comes with various other programs such as IccToXml and IccFromXml. I forget where I got it from. Possibly

For example:

iccDumpProfile.exe %ICCPROF%\LargeRGB-elle-V4-g10.icc ALL

One part of the text output is:

Contents of redTRCTag tag ('rTRC' = 72545243)
Type:   parametricCurveType
FunctionType: 0000h
Y = X ^ 1.0000

I have no opinion on whether Elle’s profiles are better or worse than others, in general.

@Entropy512 Elle has an explanation somewhere on her website with an ODT file showing annotated calculations. At one point, I asked @jdc (RT dev) about the differences between the transform matrices. If I recall correctly, he implied that he carried over the decimals, whereas Elle considered the encoding while maintaining her well-behaved colour profile criteria.

I said it is the simplest option, not the only better one :wink: It’s perfectly fine to generate a profile using RT’s ICC creator. It’s just a little more work.

If a user already has RT, I’d consider anything that requires doing something outside of the application (such as grabbing Elle’s profiles) to be more work…

I get what you’re saying, but I’ve found the work it took to get them to be well-worth the effort. It was those profiles that taught me the independence of their color and tone transforms; I used to wonder why folk were complaining about ‘sRGB’ in regard to tone transformation, because I had a set of sRGB profiles that included one with ‘g=1.0’, which is really an ‘identity transform’ that is, doesn’t change the data. i use them as working and output profiles (heck, sRGB-elle-V4-srgbtrc.icc is the display profile on my tablet, too lazy to make a calibrated profile…) in a variety of situations.

A very valuable asset.

ICC Profile creator, allows you to create a variety of ICC profiles on demand

You can choose :

  • Primaries : ACES AP0, ACES AP1, AdobeRGB, Prophoto, Rec2020, sRGB, Widegamut, BestRGB, BetaRGB, BruceRGB, Custom

  • Tone Response Curve : linear (gamma = 1), standard g=2.2, standard g=1.8, BT709 (gamma=2.2 slope=4.5) , sRGB (gamma=2.4 slope=12.92), Lab,…, Custom (gamma, slope)

  • Illuminant : D41, D50, D55, D60, D65, D80, stdA 2856K

  • ICC Version ; ICCv4 , ICCv2

  • Your description

  • You can save in the folder of your choice.

@afre : I think the differences with Elle Stone’s profiles are zero or minimal, obviously for the same primaries, TRC, etc.


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Yes, at least not enough to make much of a difference. Of course, people are free to arrive at their own conclusions. After all, it is open-source. :stuck_out_tongue:

@snibgo, thank you.

iccDumpProfile from works perfectly and ‘ALL’ gives a clear analytical expression of the curve.

./iccDumpProfile RTv4_Large.icc ALL

displays this for the RT included RTv4_Large.icc:

Contents of redTRCTag tag ('rTRC' = 72545243)
Type:   parametricCurveType
FunctionType: 0004h
Y = 0.077393 * X + 0.0000  when (X < 0.0393)
Y = (0.9479 * X + 0.0521) ^ 2.4000 + 0.0000  when (X >= 0.0393)

and my linear ProPhoto (RTv4_Large), from RT ICC Profile Creator:

./iccDumpProfile RTv4_Large_Linear_g=1.0.icc ALL

Contents of redTRCTag tag ('rTRC' = 72545243)
Type:   parametricCurveType
FunctionType: 0000h
Y = X ^ 1.0000

@ggbutcher, than you for the explanation. It is always the best to read the specification. Now, when I know it, I can run iccDumpProfile and actually understand what it does.

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I can only add it to the input profiles can`t seem to ad it to the output profiles,
How whould i do that ?

I store my output profiles in:

It seems output profiles are also picked up from

then RawTherapee Color-tab |’ output profile’, show me the output profiles.

I am on Debian Linux, but my case is not Debian package standard, since I build from source with:

Color Management addon - RawPedia states:
'They must be installed in the RawTherapee “Iccprofiles/output” folder or in \windows\system32\spool\drivers\color for Windows and /usr/share/color/icc for the other systems. ’

Another way to find the path(s) is to do a system wide search for existing files. I tend to be forgetful and that is the quickest method for me to double check.

AFAIK that’s not entirely correct.

Once you have found, created, or downloaded your desired output profile, you only have to put it in the folder set in your Preferences.

Obiously there are default locations for color profiles, but we are not talking about standard/default profiles here, so the most convenient way to manage your custom profiles is locating them wherever you see fit. AKA the folder specified in the Directory containing color profiles setting.

And if I’m not wrong, all profiles placed in that folder will be shown in both the input and output profiles comboboxes, but no profile will be shown from any subfolder inside that one.

In my very personal opinion, there’s a much better explanation about color management in the Spanish RawPedia Color Management page, where everything is explained step by step and in a much simple way. However, it is indeed a bit outdated (I can think about where to find Nikon profiles, or a few nonworking links, for example) and there are a lot of technical terms everywhere, so I’m not really sure how online translators will work here…

@XavAL, Thanks. I see now that I have preferences | color management | ‘directory containing color profiles’ set to: “home”/.config/RawTherapee5-dev/profiles. That explains why that directory plays a role, for me. I had forgotten this setting. However I have rather few profiles there and RT sees many more (output profiles).

I use preferences | color management | ‘directory containing color profiles’ directory for my calibrated monitor ICC profiles and printer soft-proofing profiles.

Yes, I see the same thing.

Yes, I believe the profiles in system32\spool\drivers\color are also loaded. But as they are system profiles, it is not advisable to store your own custom profiles there.

Yep. Forgot those, sorry. That’s a perfect location for them all.

As @Thanatomanic says, there are other profiles available system wide in the default folders pointed to on RawPedia, but it is not advisable to use those locations. And in my opinion it would be even better using a folder which is not inside a hidden parent folder (.config). That way it would be easier to back it up.