Red Rhododendron... why are some flowers so difficult?

Ya I think close with the upper one tending to be a bit more towards a pink…


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.

1 Like

Brightened the flowers; darkened the leaves. Also pushed the green more in the leaves. Added some gloss to the flower petals. :slight_smile:

1 Like

Halina3000,
Further to my previous comment, I’ve 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 can’t resolve the issue to your satisfaction in post-processing.

I’m curious about that, having assumed my entire lens collection is “achromatic”. If you have a couple of example shots I’d 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 …

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. It’s 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 haven’t tried a base curve edit to be honest , who knows.

But, how do you isolate that difference to the lens?

We’re not? It’s a reply from you on a post from priort where he/she discusses the same pictures but processed with 4 different profile settings.

In the raw file, the channels are very slightly clipped :

The image posted is well over-saturated. Whites below indicate clipped saturation, not clipped brightness.

Red flowers do have some green in real life but over-saturation pushes the captured green channel down to zero. So the flowers in the posted image are only bi-chromatic e.g. red and blue w/no green. Purple casts can often appear - a sure sign.

Contrary to popular belief, shaded colors are more saturated than brightly-lit.

One way to over-saturate an output is to edit in PhotoPro or Adobe color space to taste and then post straight to sRGB for the web: gamut- clipping can occur.

HTH.

It started as a reply to @Ally-007.

Hey @ggbutcher, he is referencing an older post of yours (a bit out of context, of course). This is the one, he is referring to:

Just, sayin… as you might not have realized.

1 Like

Oh, you see it like that. If you see the comment that was quoted / replied on, it was a different one then how you see it :slight_smile:

1 Like

Ack. Forgotten I’d even posted that… :crazy_face:

Still interested in the lens subtopic. I still think modern lenses are largely achromatic, but I do realize there isn’t perfectly uniform power distribution through any one of them. Simple to measure, just shine a full-spectrum light through one and take its SPD measurement, then compare it to the reference measurement taken directly off the light. Oh, another application that needs that i1Studio I never got around to buying…

1 Like