do you guys have any tips how to handle overexposed sky in darktable if the RAW is not clipped and still contains the information?
The thing is that I just can not make the images look nice when i try ‘exposure’ module and step the exposure down so that the sky starts to appear blue again. This of course affect the whole image. I tried the masks - gradiant or brush or path together with parameters (g and/or L mostly). This usually selects the sky (to some extent) but the edges between the sky and roofs/towers/trees are still very unnatural. I tried to play with feathering and blurring of the parametric mask but it’s still looking very weird.
Do you have any tipls how to handle overexposed sky during post-processing if there are a lot of objects interfering with the sky?
Sigmoid or filmic should help out of the gate but the tone eq is your tool and there are other ways as well… I would share one of your images and learn from all the edits and tips you will get…
Raw overexposure cannot be fully recovered. The highlight recovery module can help with that, but it’s all ‘guesswork’.
The non-blown parts are another matter, tone equalizer (which is actually a cleverly masked exposure correction tool) can help with those. Masking always entails a risk of halos, so be careful.
Can you share a raw? Maybe in the PlayRaw category, with a suitable licence? Instructions are in this post: About the Play Raw category.
Ok, here is one example of raw file (different one, without any people :))
The sky is overexposed, i tried paramettric mask but then the edges of the trees look horrible
Best if you post to Play Raw category with the (autogenerated) licensing so people can post their versions. Can find previous examples in that category to see how to post.
I have a simple approach to editing. I adjust the exposure module to give the best looking highlights (sky) without using any localised mask. At this initial stage I don’t care how dark the shadows are. I then apply local contrast and the shadow and highlights module (usually at the default values. If the shadows are still dark I usually then go to the color balance RGB module and use the shadows brilliance slider to brighten the shadows. If I still need more I then use the tone equalizer module to lift the shadows. The beauty about this method is that I am not having to personally draw any masks to select the shadows. Also using three different modules to lift the shadows reduces the risk of artefacts which increase if a single module alone is used to fix the shadows.
However, if after all this I still need to lift shadows or regions more I may consider using additional instances of exposure with localised drawn or parametric masks. But this is usually only after all else has failed to give the final result I want.
This method is very quick and easy to use. If you post an image in play raw you can see how my method stacks up against other methods.
BTW, some of your unnatural edges are chromatic aberrations that could easily be handled by the raw chromatic aberrations module. The green and magenta fringes are chromatic aberration.
@catchman
I don’t think there’s much you can do – you should underexpose, protecting the highlights, raising exposure later in darktable. All the highlight reconstruction methods work by using undamaged data to guess what the blown parts could have looked like. When large areas are blown in all channels, there’s very little the algorithms can do. In your image, first the green channel gets blown, then green and blue, and finally all three.
Arriving at the famous “we had little sun and the sky was grayish, but now it looks like a surgical appliance” look
I don’t usually care about overblown skies as I do not compose a lot of sky into my photos, but if highlight inpainting fails, it is quite easy to reconstruct a featureless sky of any color, eg with color balance rgb (in the 4 ways tab, tint the highligths blue, preferably the blue taken from the non-blown parts, fiddle with the masks if necessary).
That is the “wrong” way to work with exposure in DT. Instead, you should adjust it for the mid-tones, without worrying about the shadows or highlights. That is, you use exposure to put the mid-tones where you want them and then use other tools, such as tone eq and filmic, to bring shadows and highlights back. Usually there’s no reason to use masks for this.
It’s important to understand that it’s impossible to clip the highlights before the tonemapper (filmic or sigmoid), and so they can always be salvaged (assuming they weren’t clipped in the first place).
In this case, expose for the building and then use tone eq or white relative exposure in filmic to bring the sky back in range.
You’ll probably need both for this case, and a bit of added local contrast:
if you use only filmic, you have to lower the global contrast or accept strong compression in the highlights. You won’t get as much compression with tone equaliser, but the required correction is probably too much in this case.
So I usually end up with tone equaliser to tone down most of the clouds, then filmic to get everything I want in range (highlight reference, and contrast, have a look at the options tab as well, the contrast options for the hightlights and shadows do have an effect). And then I’ll probably add local contrast (Diffuse or Sharpen preset, or the Local contrast module).
To be clear, that’s for images where the sky is not clipped in the raw file!
