Thanks for your answer Glenn 
I was referring to Auto-matched camera profile:
where RT selects the appropriate primaries for your camera.
As seen the screenshot, there’s another setting (Custom) where you set the precise profile to use. But now I don’t know what is the fallback if you select Custom but doesn’t choose any profile or the profile is broken. I guess it would fallback to Camera standard, instead of Auto-matched.
Hi 
That made me confused too 
But you can find it out by comparison - with switching to “No profile” or “Camera standard” while watching the Working Profile Histogram and/or the Preview Picture at the same time.
Regards
It’s not just appropriate primaries. Auto-Match Camera Profile is where the DCP profile in your data/dcpprofiles directory has a manufacturer and model that matches the manufacturer/model in the file’s metadata. Nearly every DCP profile has a HueSatMap (aka base table), not just color primaries for dual illuminants.
I believe Camera Standard is what happens if there is no DCP profile but there is color matrix data in camconst.json - effectively the same as a single-illuminant matrix-only profile.
Use Embedded, if possible, is seen for DNGs - I’m not sure if any other raw format has embedded profile data. Be warned - a LOT of DNGs have very broken embedded profiles.
I don’t think you can choose “nothing” and have the radio button stay on Custom? And if you choose a broken or inappropriate file, you get garbage colors.
I haven’t looked, but I’d bet RT and Elle used the same numbers, or close.
A working profile is less about being ‘precise’, and more about being ‘big enough’ , and ‘well-behaved’. @Elle has a good article on that:
Articles and tutorials on Color management, scroll down to C.3
Converting the working space data to sRGB AND saving it to JPEG WITH the sRGB profile does two things: 1) it gives color managed viewers the information to convert the image colors to the display profile, and 2) for non-color-managed viewers, prays that the display is something close to sRGB.
The word ‘precise’ in this endeavor really is only pertinent to the characterization of the input and output devices. And, (Mister Grammar Fairy here) the better word to use might be ‘accurate’… 
Too many things inside a profile, to my taste. When I’m working with my own camera images, I always use a custom icc input profile I made myself. And judging by comparison between the real subject and the colors on my display, it works quite nicely.
When working with Playraw images…, well, that’s another story
Gosh, this topic is still very dense, to me. I believe I have several misunderstandings and many questions.
Apart from that, I primarily use RT to edit photos taken with a Nikon D750. And I have two use case scenarii:
And recently, I’ve been trying to make some HaldCLUT files for the film simulation module.
So for each case, I need to carefully think about the Color Management section.
dcamprof for my LED light source, cf. how to create a dcp for an artificial light source I tick all checkboxes (tone curve, base table, look table).dcp for my camera contain one?Now, say I take a picture of a colorchecker in D50-like conditions. What are the Color Management settings in RT that should be applied to get the expected gradation on the grey scale (other than initially doing the WB)?
Sorry for reviving this thread and thanks for reading me.
EDIT:
2023-05-24:
(1). colour negatives were not discussed, yet.
(2). simple answer: for a neutral basis (proper gradation and colours), only use the base table of the profile that’s shipped with RT. The Look Table and Tone Curve options can have obscure origins, depending on how the .dcp was made in the first place, so you don’t really know what you’re applying.
Salut, @nonophuran!
I do not want to complicate things much more — but have you studied these two interesting chapters in Rawpedia?
Have fun!
Claes à Lund, La Suède
hey, @Claes, hi!
thanks for these pointers, I had not seen that hefty add-on article to the Color Management section.
I can only sigh when I see there’s so much to read and actually understand, to be able to answer to my questions xD
Do you believe there’s enough material there to answer to my last point about neutral tone reproduction?
Thanks again, for being so responsive.
Do you believe there’s enough material there to answer to my last point about neutral tone reproduction?
Non :-(((((
It depends on how the .dcp for your camera has been made,
I have managed to find two .dcps for my camera (X-T4) – one
includes a tone curve, the other does not. If you have an X-T4
camera, I can gladly send you my .dcp :-)))).
More info here: https://rawpedia.rawtherapee.com/How_to_create_DCP_color_profiles
Amicalement,
Claes à Lund, La Suède
Hey Claes,
My nikon D750 is the only “serious” digital camera I own. That said, since I’m playing with HaldCLUTs, I’d like to know, from a fuji raw converter perspective, and from an RT perspective, what settings must be applied for “truly” neutral tone reproduction.
EDIT:
2023-05-24:
(1). in Fuji raw converter (silkypix-based), to achieve neutrality (more or less)
a. Tone — can be set to “standard” instead of “average contrast”
b. Highlights controller — offers a “Dynamic range” section, which can be set to zero
c. then, you can play with the exposure bias slider.
d. Camera setting — choose faithful natural or faithful standard, they’re quite similar in this case.
Side note: I don’t have a procedure for Nikon NX Studio, yet (i.e. Nikon’s Neutral, Standard and Flat Picture Control profiles all have tone curves baked in them)
(2). For RT, use an auto-matched camera profile, with only the Base Table enabled. Simple.
Last time I had a running copy of RT, it had a Neutral processing profile which did just that… That’s not the same as the input profile; if you do nothing else, I think RT just defaults to the camconst.json color matrix for your camera.
Salut, @nonophuran!
I am sorry: I do not really understand what you are after 
Words like “Natural”, and “Faithful” as used in the camera settings you
presented above are rather vague. (Not to talk about the “Faithful Standard” color,
which actually implies an “Unfaithful Standard”, as well.)
I wonder whether you mean something like “100% colour match”?
I.e. your object has a certain colour, let us call it XYZ. You take
a (RAW) photo of that object, and you would like to develop it so
that the object is presented on your monitor exactly as XYZ.
Is that a correct assumption?
(Then, perhaps, you would also like to distribute your image
and have it look exactly as XYZ on every monitor all over
France? And/or print the image in offset, litho, intaglio, screen,
&c &c &c — still looking like XYZ…?)
The closest I’ve come to something like that was: My first color management experiment
By all means not perfect, but pretty good for a non-professional set-up…
Amicalement,
Claes à Lund, La Suède
this is Fuji’s own take on colour, in the raw converter they provide. Do you happen to have this piece of software? else, what would be the in-camera profile you would choose in order to achieve neutrality (which I would define here as faithful greyscale gradation)?
I’m not sure I want to have such a firm constraint. Maybe my line of thought translates into this, but I don’t know.
The setup I’m thinking of: say I take a picture of a colorchecker in D50-like (or D65) conditions (essentially having it outdoors with natural light, without reflections, glare, etc.).
Does that make things clearer?
So for the tone ramp a linear profile and good exposure would be faithful to that as you wouldn’t introduce any large or biased compression…color could be shitty or way off and still meet that criteria in the profile so you need a decent matrix for color. You could use the Adobe Profile editor to make a linear DCP for your camera and tweak color as well
D75_5446.NEF (25.9 MB)
D75_5446.NEF.pp3 (13.6 KB)
(no particular licence for this picture, of course)
So, trying it out for myself, with this data
spydercheckr_reference_data.pdf (200.8 KB)
after picking the WB on the grey card exposed to the sun, I adjusted the exposure so the brightest patch would get to L = 97% approximately.
The other grey patches fall pretty well where they’re expected to, in my opinion (not talking about the a and b values, though).
Notes:
base table is ticked,A few minutes before that, with a different lens and orientation, the sun was behind clouds. With a similar processing approach, I get some compression in the shadows (i.e. they appear lighter than they should, but that could be due to the hand-held and imperfect setup )
If I understand my D7200 correctly, when shooting in RAW you don’t need to set up anything in the camera. Everything you can switch on is used only for the in-camera development of the JPEGs. Therefore the input profile of RT is just used to map the values of all four sensor channels to the rgb values of the corresponding pixel.
Indeed.
Back to the optional Tone Curve and the Look Table: for my D750, I think I found something relative to its origin.
That does not clarify what these two options, in this case, are supposed to do. What “Look” are we talking about? What is that Tone Curve required for? (i.e. when is it applicable?)
Since this git + google groups discussion mentioned in my previous post is almost 10 years old, I doubt I’ll get an answer about the intent of the attached look table (for the D750). But there was some debate pertaining to the quality / usability of the provided color checker shots, back then (perhaps @jdc remembers?). This is getting off topic: should I provide my own shot so it can be turned into an RT-bundled .dcp profile?
@nonophuran
Yes, I remember, or at least approximately…
The problem of the calibration charts is of 2 types (at least)
Another point to be mentioned is the nature of the grays (for example on the Colorchecker24), putting Pick in the belief that it is a good balance of whites comes up against 2 false inferences.
And
Jacques
