What I found most difficult was bringing the blue flowers in line with real life, which is hard to do if you don’t know what they should be in the first place: Big Swing Salvia. The problem I had was the blues started out of gamut, and the corrections would send them to a different hue. I’d say your second was closer than the first
that would have been a better reference, never mind, close enough.
@Dave22152 It might be the angle or composition (or just me) but I feel like it is jamming its beak in the flower rather than taking a delicate sip or lick. 
@Underexposed Yours still stands out because the bird is well done (not in the edible way 
).
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@afre: That’s funny. 
Yes, he was very uncooperative and had poor table manners that day.
At a plant exposition at Chateau de Chantilly, I met a art book editor. I noticed he had some art reproductions of photos and paints of salvia and by chance there was one of Big Swing salvia. he said it’s a production from north american plant breeders.
It’s a gorgeous plant.
The color was dark blue or cobalt blue without any violet color.
I wonder why it is not possible to get this color without some trick (color zone…)
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You can get the basic hue, but the fine gradations of that hue are lost in sRGB without a well-considered transform
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Others will have better technical explainations, but the problem is that the blues were out of gamut and were difficult to bring in line without seriously changing the color.
Do you have a sidecar for your second version?
long story short, I’ve been using a LUT based workflow* for all the Play Raws that have come along recently and one of the LUTs I use I made in DaVinci Resolve - some of which includes a Kodak 250D negative film emulation I purchased from a colourist - so while the secret sauce is hidden inside the LUT, I’m still not sure where I stand exactly in terms of sharing it far and wide.
a lot of people on these forums seem pretty cluey about licensing so perhaps someone could comment on the legality and ethics of the situation? If it was entirely my own work I’d be more than happy to share it of course.
anyway, the point of mentioning all that is that loading the sidecar won’t give you the same result because the LUTs will be missing. Here it is anyway though if you’re interested.
_MG_0113.CR2.xmp (77.3 KB)
but I thought this might be just as useful without having to go through the process of loading the sidecar:
the area of interest is the part of the curve on the right, I’ve pushed the blues and indigo region towards green (i.e. made them more blue), increased the lightness, and decreased the saturation.
the other changes to the hue curve are just done by eye to create a more pleasing colour harmony in the reds and pinks of the flowers on the left of the image.
RE: the comments above about why its not possible to achieve this in colour zones without a well-considered transform, the “reconstruct colour” option in the highlights reconstruction module seems to perform adequately here for me, but the LUT I use also has some gamut mapping built-in that may also be helping.
*the purpose of which is to be able to shoot stills and video on any given project and have them match perfectly.
Yes, free lenses agree with our ethical feelings about software, sharing, and fostering an environment for learning. In addition, the creative commons license for raw files, etc protects our users and the forum, and we like to make sure people understand all of that clearly.
That depends entirely on what you agreed to when purchasing the LUT. I’d wager a guess that you bought a license for you/your business to use the LUT for commercial/non commercial work. I’d also guess that you’re not at liberty to share it freely, but again, you’d have to look at what you agreed to when you purchased it.
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I seem to recall there were some Channel Mixer coefficients that could tame out of gamut blues:
https://discuss.pixls.us/t/darktable-3-0-for-dummies-hardcore-edition/15864
I also remember some guidance for the Filmic module to change Preserve Chrominance to No if there were odd blues.
Both of those seemed to work for me.
I agreed to send a guy money in exchange for the powergrade 
no terms and conditions, no EULA, or anything like that. So I’m not sure if there are implied/default copyright protections or not.
as far as I’m aware this guy is a freelance cinematographer and colourist and just sells these Powergrades he’s developed as a bit of side-income, i.e. its pretty laissez-faire.
anyway, it hardly seems worth worrying about, far less could ever be gleaned from me sharing a mysterious black-box LUT than what the man himself has to say about how it works:
what I should have done is kept a better record of the steps taken to modify the node structure in Resolve so that the LUT would work as expected in darktable. That’s going to be the most useful bit for anyone looking to pursue a similar workflow here, although I’m sure most would arrive at the solution in fewer iterations than it took me 
I think that’s the key, if you have a solution that works then how could we use the available features of the software to replicate those results.
the whole approach is predicated on having a preexisting workflow in DaVinci Resolve that you’d like to “port” certain aspects of over to darktable, which I imagine is pretty niche.
even then, the only difficulty really is that the film emulation aspects I wanted to use expect the Arri LogC gamma and the Arri Alexa Wide colour gamut as input, so I have to create a dummy node graph in Resolve that first converts to the Arri colour space from whatever colour space the LUT will be applied to in darktable. This is where I got a few whacky results at first, assuming the wrong colour spaces and not getting the gamut mapping right in Resolve to handle edge cases.