I found that the red channel gets blown easily with red flowers, and that makes editing afterwards difficult.
In addition, there may be a bit of UV in many flower colours, which the camera can detect (as blue), but we donāt.
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The gamut compression slider in CC module can help and the colorfulness sliders also are nice to apply to help tweak those gamut/saturation issues
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Hereās my attempt. Tweaking color calibration to bring the blooms in line helped a lot
IMG_7089.CR2.xmp (11.2 KB)
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Edited in Gimp.
I lowered the exposure by about one stop and lifted the green channel using the red channel in brighten mode, then i blended the two layers in luminosity mode.
Hard to get a good contrast without blow out the reds and keep colors in gamut.
I see this topic has come back to life again 
Give it another month or so and I should be able to compare with the real thing again.
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Not sure how many of these edit were done with the default DT web safe srgb profileā¦ It seems geared to offer a perceptual rendering intent and although you can select rendering intents I am almost certain it doesnāt have the luts to render themā¦ Switching to an icc from icc consortium you can change the rendering intent which in the case of flowers will also change the resultā¦
Here are 4 exports of my editā¦ First one is perceptual with DT srgb profile and the second is relativeā¦they seem the same and the next two are with the icc from the icc consortiumā¦First one perceptual which is a good match for the 2 from DT and the last is rendered as relative and I actually like how it renders in this caseā¦
IMG_7089.CR2.xmp (9.1 KB)
sRGB_v4_ICC_preference.icc (59.5 KB)
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Todd, they all look about the same to me. You embedded the relevant profile in each (proper practice), and most browsers are going to convert the image to sRGB (default) for rendition.
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The first 3 should be the sameā¦you donāt see a difference on the last one???
How about in this screen shotā¦
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@priort, Thank you for the sRGB_v4_ICC_preference.icc from www.color.org. Different rendering intent do result in different rendering.
I do see a difference between the last two frames, also in original post, on my monitor.
They have another one on the same page called appearanceā¦ this one is supposed to help preserve color when there are color space conversions at least I think this is what it is forā¦ its gives a slightly different result not sure I fully understand the difference between those two and this newer iccmax yetā¦ Might have to read a bit to fully understand itā¦
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Bottom one is a teeny bit darker. Hues look the same thoughā¦
Ya I think close with the upper one tending to be a bit more towards a pinkā¦
IMG_7089.CR2.xmp (20.7 KB)
I tweaked color calibration until the flowers became red. I had to drop saturation afterwards. filmic v6, with preserve chorminance in luminance Y mode.
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Brightened the flowers; darkened the leaves. Also pushed the green more in the leaves. Added some gloss to the flower petals.
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Halina3000,
Further to my previous comment, Iāve also noticed that camera lenses can differ considerably in how well they convey colours at the red end of the spectrum. I suspect that some lenses filter out some light frequencies to some extent. So it might be worth trying a different lens or two, and comparing the results, if you canāt resolve the issue to your satisfaction in post-processing.
Iām curious about that, having assumed my entire lens collection is āachromaticā. If you have a couple of example shots Iād be interested in examining them.
Even on my phone they look different here.
The first 3 have a more magenta thing going on.
It is subtle on one hand , yet next to each other very clearly visible on the other ā¦
Bright luminous saturated reds are also one of the problem areas for filmic v6/v7 gamut mapping.
People switching to sigmoid or filmicv5-no-preserve for those kind of situations.
Personally i set it up with filmic, but then render out to a rif in rec2020. This disables filmics gamut mapping basically , and give better results in those cases. Itās a preference thing though. And also one of the issues i have with Darktable , is that there is no way to control the gamut mapping. So i akways get a magenta look in DT, while the export to rec2020 has no magenta cast in those reds.
The football team of my son plays in bright pure ree shiny shirts (50% red, 50% white pattern) .
In rendering pictures of that in DxO with a profile from Color Fidelity , i get good reds without issue. Rawtherapee with the same profile and a simple logencoding for tone mapping gives very pleasing results , and the same looking reds.
Even with the same profile converted to ICC with dcamprof, i have a hard time to get Darktable render the reds in a pleasing way. Even sigmoid and filmic5.
Filmic6/7 but exported to rec2020 are only ones being close (with the regular standard matrix in DT btw).
Bright, saturated reds just seem like a DT problem at the moment to me. I havenāt tried a base curve edit to be honest , who knows.