Colorchecker - auto color + luminosity correction. Is this currently possible?

See the video below.

Is this process of automatically correcting both the color and luminosity of an image currently possible in Darktable? I use this function in both Divinci Resolve as well as 3d Lut maker.

I see an image of a Macbeth/ColorChecker chart in one of the modules but don’t think it is for this purpose? Just getting to know darktable.

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Yes, you need to use darktable-chart.

Watched the video; that’s neat!

If I had to match multiple cameras shooting the same scene, I’d want this. As a still photographer, not so much.

Depends on the kind of photography you do… shooting commercial work or things where you need to represent your colors correctly, this would be good.

Soooo, bear-o-little-brain here, I’m wondering how different this method would be versus just making a ColorChecker profile for each camera…

I’ve got camera characterization on the brain right now, all this sitting-inside has me exploring ways to measure the spectral response of cameras without spending ~$5000US on lab-grade optical apparati… I’ll report out here in a separate thread when I have a cogent plan.

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Do you mean an input profile?

yes.

It does luminosity matching?

Thought it looked more like a color profile type of utility. Ill have a look.

There is a whole industry of people shooting textures for 3D rendering, photogrametry, spherical HDRI…

All (who are doing it according to industry standard best practice) depend on colour+luminosity correction.

Textures need to all sit in the same ‘space’ for realism and consistency.

Thanks to some mighty fine discussion on this forum a while ago, we’ve become quite familiar with “scene-referred” workflow used in the motion picture industry. There, they handle luminosity among sources with 18% middle gray exposure. We didn’t talk so much about color, but any of the other lit I’ve read describes use of color targets under the same illumination to produce camera profiles anchored to that illumination. Recently, I’ve been researching camera calibration using spectral sensitivity measurement, and I was presented with one source that attempts to inform the video cabal about such tools to use on the set:

Camera Characterization - Hochschule der Medien (HdM)

What you’ve brought to the discussion in the Resolve capability is an interesting take on this endeavor…

Interesting ill have a look… In the absence of ideal conditions those of us who hunt for texture often do so out in the wild under different conditions (shade, overcast) or when possible using cross-polarization in the ‘studio’ .

Colour+luminosity matching is the best way to bring these disparate sources into the same space. I’m surprised more image processing software hasn’t integrated this functionality already. Divinci Resolve is the only one to build a utility directly into the software. But then they are ahead of the curve on a number of fronts.

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Ill have a closer look at this tonight… thanks!

But the feature is a necessity for Resolve, but not so much for still photography.

Ahhh…yes

This is much different than making a ColorChecker profile for each camera, or profiling…As it neutralizes any tone curve added by camera/software.

  1. it removes or at least standardizes a particular ‘tone curve’ something which definitely changes between cameras, but also software (and is often hard to completely disable in software)
  2. tone response to luminosity seems to change quite drastically between lighting conditions and other variables… no matter how ideally illuminated a ColorChecker is you will never get an image with the ‘correct/idealized’ values across all patches, or even the grey-scale patches…

Having experimented with colour+luminosity matching for a while now I can say that it
is a constant fight that requires special tools. Camera calibration and profiling doesn’t get you very close. I try to allow the 3D Lut creator utility to do as much of the corection as possible, disabling as much processing and colour management as possible in Rawtherapee (have been using for a while) or Darktable (which im just picking up).

I would argue thats not right.

There is a whole industry of people shooting textures for 3D rendering, motion graphics, video games, graphic design, photogrametry, spherical HDRI…

All (who are doing it according to industry standard best practice) depend on colour+luminosity correction.

Textures need to all sit in the same ‘space’ for realism and consistency.

There are quite popular siblings in Poland that are doing weeding photography. In they course about colors (“Władca barw” cost around 10€ but only in Polish) they show how they are using Colorchecker.
They are photographing it many times per one weeding. Inside church in few places (could have many different light lamps), in the evening (when street lamps have different kind of light sources), in the hall.


They use global profiles (dual illuminant, with custom changes they would do inside Lightroom almost every time, in they words “profile from profile, changing proper colors to nice looking colors”) to make photos from Nikon, Olympus, Fuji and Sony looking the same and then using individual profiles for group of photos from each event (or even only for one photo). Thanks to this most of they photos they simply mass import to Lightroom and then export to jpeg without doing anything. If there is need then they use tool from x-rite to generate profile from Colorchecker and apply it only to few photos that need it, standard adjustments and done. Then they could forget about this profile.
So they can change this picture

into this with few clicks

This looks like really fast workflow to me. They are providing they clients with hundreds ready, good looking photos in few days after weeding. Would be nice to have option like “Generate profile/style for individual picture(s)” in dt.

Here’s a tutorial for darktable:

I just want to make sure it’s clear that what I’m asking about color + luminosity correction is different than camera/sensor profiling. Have a look at the video. Its more than just profiling for a basic color matrix adjustment. In this utility, you get the exact values of the Mcbeth/ColorChecker chart. You don’t get that with profiling.

Can darktable-chart do that?

an even better example…

Yep, and also it has way more steps (exporting, importing and going through many tabs) than “few clicks”.

Sorry, for sidetracking. No more comments from me not in topic.