As already mentioned the first preview is taken from the jpeg. Once you open the file it applies whatever is set aus default in your RT, probably “auto-matched low ISO” or something similar. What RT does is use the auto matched tone curve which just matches, I think, luminosity. BUT, the camera will have done a lot of things to the jpeg already, like sharpening, local contrast, color correction and maybe even slight dynamic compression. That is the secret sauce of the camera brand. And it might even be, that the processing isn’t static, but the camera tries to recognize the scene and processes the raw accordingly. So, the best way for me was to start with the auto matched tone curve and then try to match the colors, then save as a profile.
1 Like
Try with tone curve-standard and/or camera standard input profile
1 Like
I guess you will already know it, but just in case: a proper input color profile specifically made for your camera model (and if possible for your own camera) is vital if you need accurate colors. But I’m not sure if that’s your problem.
Perhaps you will have to read how to improve your camera support, because as it is stated in camconst.json (where information about your camera is stored) for your 5D MkIV:
// Quality B, some intermediate ISO samples missing, LENR samples missing so White Levels not properly indicated, some aperture scaling missing
And that quality B may give some hint about why RT doesn’t handle perfectly your images. Not sure, but maybe worth giving it a try?
2 Likes
Yes, I’m aware companies make that “secret sauce” and IMO, Canon is known for a great skin color, just like Olympus has been known for fantastic blues, out of the box. But alas, only Canon’s own DPP really reads ALL Raw values accurately. Not surprisingly so, considering it’s their native tool.
However, I’m on a mission to create several profiles for RT, depending on the light or skin colour conditions. While it won’t be 100% accurate, it will be close enough and much better than default one.
1 Like
I tried. This is more color-related issue (particularly skin color). However, I’m getting there with several tools I used in RT, from RGB curves to Lab adjustments.
1 Like
Thanks. It does produce better results! The only thing I switched back was AMaZE demosaicing instead of pixel shift (as the manual says, pixel shift is for pentax/sony cameras only).
You’re right Xaval for color profiles and too bad it’s on Quality B. That explains this color shift, particularly in skin rendering. But I’m close on making my own.
1 Like
Nothing much… this is more color related issue, but as I said to others, I’m getting close. 
I don’t know if this section of one of my videos might be of any use to you…ignore the stuff before and after, but the CM bit might help.
6 Likes
For my Nikons D610 and Z6 the best colors and tonality were with Adobe .dcp profiles. You can read in Rawpedia how to get them.
Allow me to reiterate @XavAL’s note.
Please consider providing samples for us. RT is only as good as we make it to be. 
1 Like
Thanks, very useful video. I think I watched your videos few months ago.
Alas, I can’t change much. I only have ‘no profile, camera standard or custom’. I can either opt for no profile or custom.
Also, in the output profile I don’t have ‘profoto’ in RT. Only those v4_SRGB profiles, but that’s minor problem. Still, I saw in your video, you were using profoto both in working and output.
Tell us what you want exactly, then we can tell you how to set it.
RTv4_Large is the open source version of ProPhoto, which I think is copyrighted.
Well, I managed to make a profile on my own that looks similar to default Canon. I was just commenting that Canon 5dmk4 doesn’t have an embedded profile, as he was talking about that setting in his video.
Thanks for RTV4_Large tip - didn’t know that. Will check it out!
Just to clarify, there are at least 3 different uses of profile. Colour profile as in ICC profiles, RT profile as in workflow steps and sidecar, and camera profile as in calibration (actually profile is a more accurate term but I am using calibration to help clarify the term).
The order of workflow is to profile your camera, use it as an input profile, use an ICC profile as a working profile and use the normal RT workflow to get the colours and look you want. The first two steps are technical. The last one is artistic. I.e. the default Canon aesthetic is actually an artistic one. In open source raw developers, you aren’t limited to one look. E.g. you can take photos using a Canon 5dmk4 and give it the appearance of a Leica ('sup L haters).
No. Your camera is an analytical tool that (within some boundaries) captures exactly what the scene presents. Your brain interprets things vastly differently. If you want an accurate digital representation of your scene you need to profile your camera using a color chart. Anything else is a subjective look that you, me, Canon, Olympus, etc. can define arbitrarily. With enough effort it is 100% possible to simulate any ‘great skin color’ or ‘fantastic blue’. And in terms of how RawTherapee handles things: stick this effort in a preset and you’re good to go.
Edit: just in case, I know things can be a lot more nuanced than this (considering demosaicing, noise, etc.), but my point is that color and tone both have an analytical and artistic side that should be treated differently.
1 Like
Anyway, what we are describing is difficult to grasp at first. It is a bit of a paradigm shift; however, it is the proper application of the workflow. Adobe and other commercial entities hide this process from the end user.
That said, I do understand that when you are beholden to your clients you have to deliver the look. What we are saying is that it is better to get the light, science and calibration correct before applying the look. It will take much more work and getting used to, but the end result is actually better than what you would get from DPP or Camera Raw.
1 Like
This is correct. An addition: the working profile should be large (e.g. Rec2020 or ProPhoto), the output profile for web should be sRGB, and for print you ideally need a specific printer profile for your printer, or any large profile with the caveat that you need soft-proofing if you want to emulate how your print will look like. In both cases you can deviate if you’re sure about what you’re doing.
1 Like
No, I’m not comparing any numbers, nor do I care for them. Artistic and environmental things are the core points for me when I’m deciding colors and tonality. However, I was pointing out that every company had a certain “secret sauce” that put into their JPEG engines and settings. So, Olympus was known for great blues and vibrant images - out of the box (jpg), similar to what Canon did to skin hues.
Now, of course everything can be tweaked in RAW or other editors. But, the issue for me, why I started this topic, was that I was way more satisfied how Canon rendered those colors in the thumbnails than default RT. And was merely asking what was happening and if I could tweak that initially, during import.
People explained to me what RT does and how it sees the RAW and it’s all clear now.
1 Like
And anyway, thanks everyone for these immensely helpful answers. I learned a lot.