I would like to understand the behaviour of DarkTable. I enclosed one photo made my granddaughter of our photo walk. The file is RAW from OLYMPUS camera XX-2. If I switch on the clipped colours I can see that most part of the sky is clipped. If I open the same picture in other editors (Affinity Photo, Luminar, Zoner Photo Studio) the sky is quite ok. I know the picture is not interesting but from the point of the behaviour of Dartable,PB172220.ORF (18.4 MB) I would like to know where is the problem.
There actually is no problem. Arguably the problem is with the other RAW editors because they show you a ‘false’ starting point
A lot of RAW editors have already applied some settings to the RAW file the moment you open them. darktable and RawTherapee show the RAW file as clean as possible (depends a bit on the settings you auto apply).
You will end up seeing a flat, somewhat washed out image and it will also show you the ugly clipped parts, sometimes in pink, when they exist.
I mentioned that the problem is with the other editors; That depends on how you approach your editing. I like my starting point to be as clean as possible and have only very few things that are applied automatically (very basic stuff like: lens corrections and demosaic).
There are ways to start with settings already applied in both darktable and RawTherapee. Some are in the preferences menu and some you can create and apply by yourself or automatically (you seem to be a darktable user: have a look at styles and presets)
Thank you for your comments. There may be a problem of how editors read the RAW data. A long time ago I made a user setting of the histogram in Olympus XZ-2. The darkest point is 5 (not default 0) and the lightest point is 250 (not default 255).
I would carefully think that this has nothing to do with how your camera writes RAW files or your editor reads raw files. This is just a warning on your camera’s display telling you that you are about to clip highlights or shadows. It’s just a visual warning. It does not protect your image from having blown out highlights
The fundamental problem is that the high values were clipped in the camera. Affinity is very likely applying some sort of highlight recovery to render the image you posted. I know RawTherapee has good highlight recovery, not sure about darktable but would be surprised if it didn’t.
Recently, I’ve been exposing to preserve the highlights. A lot of times, the rest of the image is too dark, but I find it’s easier to lift shadows than it is to re-create values that were lost at the time of capture. This applies to any raw processor, free or commercial.
The basic problem arises, when there is more light than the sensor can measure (in a linear way). Depending on the color, this happens at different points for different color channels on the sensor. So, you get ugly false colors because one channel is saturated while the others may not yet be. Some of the information in the picture is lost.
This is the basic situation for every raw editor. Then the “magic” starts in “recovering” the highlights. There are different methods that may give you more or less satisfying results. In this respect raw editors may differ.
darktable tends to do only few things “by its own” and give the user the control. So, images may look less good in the beginning but you can achieve great results.
Thomas_Do, thank you very much. I went thru your workflow and understood that the main influence is from the highlight reconstruction module. The other editors I have tested must have some automatic algorithm to make a highlight reconstruction. I would like to use mainly DarkTable as my main photo editor and the others for some special works.
Thank you also ggbutcher, Dinobe and Jade_NL for your time you deal with my questions.
Merry Christmas to all.
Vladimir there are also multiple ways to assess this in DT there is the raw clipped and then the pipeline clipped and ti is assess 4 ways, based on saturation, luminance, one of the rgb channels or full gamut…you need to decide what you are probing for as the display will change…Affinity by default applies a tone curve and chroma noise reduction at least…that is found in the assistant settings you can turn it off to compare. It appears your raw file is clipped so you are recreating from nothing in the case of this image
If you change the highlight recovery mode to color and use color balance and auto correct luma and go to exposure and drop by a 1/4 eV and enable the exposure comp. So really not too much and no work on tone or color…its not too bad to start given it is blown…
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