Learning to recover blown out skies

[Terry (Terry Pinfold)]

This is my attempt using sigmoid module. My xmp file may not be too helpful as I am using V4.7.

However FYI I did the following:

I darkened the image to optimise the sky and to hell with the shadows going dark.

I created a second instance of exposure and used a parametric mask to select the sky and then inverted the mask. This allowed me to separately adjust the brightness of the foreground.

I did a small threshold tweak in the color reconstruction module to get rid of some minor magenta cast.

I activated the shadow and highlights module to default values because I like the effect.

I applied local contrast to the default values because again I like the effect.

I activated the lens correction module which corrected distortion and the chromatic aberration.

I applied denoise (profiled) at default values

I activated the diffuse or sharpen module using the preset 'sharpen demosaicing: AA filter

I did a small tweak to the skew slider in sigmoid (+0.26) to add contrast to the sky without blowing out the clouds.

Then in the color balance rgb module I added about 16% vibrance, 7% contrast, +38% brilliance in the shadows and to further tackle any unwanted color in the sky the decreased highlights saturation by 51%.

This took less than five minutes to do even though it might sound complicated. I am pleased with the result, although the posted image is a little darker than on my screen in DT. This sometimes happens when I post images to the forum.

BTW, @Sean_Liu has done an nice edit using filmic V5 with no chrominance. There are lots of people who like filmic and when I use it I tend to use V5 with no chrominance. But it is a complex module to learn and I recommend Sigmoid because it is very intuitive and easy to use.

DSC04603.ARW.xmp (16.9 KB)

[Terry (Terry Pinfold)]

@123sg

My 2c FWIW.

You will have to change that to your 5 cents worth as two cents coins are no longer legal tender in Australia.

[123sg (Steven)]

Oh… I must be out of date!

[kofa (István Kovács)]

The best way to deal with highlights is to preserve them when shooting – that is, avoid blowing them out, by reducing in-camera exposure. Exposure then can be restored in darktable – in fact, the exposure module has an option to do that automatically (I took this screenshot using a photo I took in manual mode, so there was no exposure compensation dialled in the camera, but you get the idea):

The reconstruct option in filmic is somewhat of a misnomer, as the primary purpose was to soften the transition between what you set as white (white relative exposure on the scene tab) and the surroundings. It is not there to fix raw clipping: filmic has no idea what raw pixels were clipped, it’s close to the end of the pipeline.

In your photo, turning off all curves (incl. filmic) and dropping exposure shows the magenta is there; it’s not added by filmic, but it may be emphasised by it, depending on the settings:

Turning off highlight reconstruction (the module, not the option in filmic) shows what we start from:

Turning on the raw clipping indicator also confirms the severe clipping; you have lost a lot of information, and can only try to cover up that fact. Restoring lost information is impossible.

Turning on the candidating mask shows which areas get some colour propagated from the surrounding area:

With the default value of 40, only a bit of the blue channel is propagated:

Read about the meaning of the masks and settings, as explained one of the developers here: Nice waterfall, shame about the vegetation blown highlights - #22 by hannoschwalm

But there is not much you can do:

Side-by-side with the default inpaint opposed:

exposure raised back, filmic back on (v7 with the defaults, only auto-picked the black and white exposures):

With my default filmic style (includes diffuse or sharpen and local contrast, too): filmic v7, but with contrast in highlights/shadows set to safe for a gentler curve:

Left: default filmic v7, right: as described above:

Bringing down the highlights a bit in tone equalizer, then dropping highlights saturation mix in filmic:

DSC04603.ARW.xmp (15.2 KB)

The sidecar is from darktable master branch (development version).

[qmpel (blends colors 🎨)]

Here is my version with ART, using balanced highlight reconstruction, dynamic range compression and tone eq with a bit of local contrast…

DSC04603.ARW.arp (13.5 KB)

[kofa (István Kovács)]

Wow! I’ll try to see if I can come closer to that when I’m home.

[arturoisilvia (Arturo)]

With DT 4.6.1
Filmic V6 No + Enable highlight reconstruction

20249327_DSC04603.ARW.xmp (8,0 KB)

Greetings!

[Popanz]

Using Sigmoid:

DSC04603.ARW.xmp (14.5 KB)

[Donatzsky (Nis Donatzsky)]

@123sg

Personally, I’ve never had much luck with the filmic reconstruction, FWIW.

As I understand it, filmic isn’t doing actual reconstruction, but is more about smoothing the transition in a way that makes sense for the image. Especially the older reconstruction methods (before inpaint opposed) can have some unpleasant transitions.

[elstoc (Chris E)]

There are some great sky edits here and it’s amazing what can be done with darktable these days but I’d urge a couple of notes of caution.

• What is the subject of the image? The more contrast you add to the sky the more it becomes the focus of the image. If I’m taking a street image, I would be more likely to crop out the sky or keep it flat so it doesn’t become a distraction. If I’m taking a picture of the sky I would similarly crop out or darken the rest of the image.
• There’s only so much dynamic range to play with. If you add contrast to the sky you usually either lose contrast elsewhere in the image or start to make it look unnatural. Particularly when the sky becomes almost as dark as the things that it’s illuminating, it begins looking wrong. Some of the better sky edits would leave the street scene in near-darkness if they were to keep a natural balance in the image (e.g. if they had been achieved just by reducing exposure).

For example, a very quick edit using just the exposure module and white relative exposure in filmic:

[Popanz]

The question is what is a natural balance in the image. A photography works different to our eyes.
If you look at your quick example: It is daylight and i’m pretty sure the street and the building wouldn’t look so dark if you’d look at them in real life. So If you now decide to raise the exposure. You would lose the details in the sky and you would get a completely blown out, white sky.

You are maybe used to that if you are an old lad like me. Photos looked like that in the past, because the dynamic range of film wasn’t as good as nowadays the sensors.

But if you would stand in this street, you would of course see a bright street and at the same time all the structures in the sky, because your eye adapts to the brightness it is looking at.
The eye sees just a very small spot and it is wandering around, grabbing all the thing (while it is adapting to the light situation where it looks at).

In the end there is a picture in your head which was puzzled together by your brain. And I think most of the edits come nearer to this picture in your head, than teh pictures from the past, where you had to decide, if you want a blown sky or an underexposed scenery.

[elstoc (Chris E)]

Yeah my example was exaggerated on purpose. But there is a line beyond which it looks wrong and I just wanted to draw attention to the bigger picture

[Popanz]

Are you sure, your monitor setting isn’t too bright?
For me your Image is way too dark. I can understand your position. But I hardly can recognize the door on your picture anymore. I can’t imagine, you exaggerated that much on intend.

[g-man]

I was thinking like Chris. The sky is not that important to me.

[Popanz]

Of course, a further possibility is to concentrate on the scene. But that has not much to do with recovering sky or not. That’s more a question of composition. On your pic the blown out and not really important sky was simply left out. But on the other hand, then it doesn’t matter, if you recover the sky or not.

Same edit as before, different crop. Leaving the sky out. I would probably raise exposure a little bit further. Anyway, I think it still works:

[g-man]

The image processing start before you press the buttons on the camera. If the sky is the important part, then compose to the sky and select the aperture/speed for the sky. If the scene is the important part, then expose to the scene and dont even take a picture of the sky. If you really want both, then you need to select a camera/lens that can handle both.

[priort (Todd Prior)]

If you mask it to where you want it and pull back the opacity to suit the HDR preset in Local contrast is amazing… actually it seems to pull down highlights quite a bit which can be helpful… you just need to finesse it to suit the image…

[AxelG]

I am close to the opinion of @elstoc in terms of editing. And yet I see, I pushed the street quite a lot but started from a very dark base point (EXP=0) and is still realistic dark IMHO and sky not over prominent…

So here is my take with current master (dev version)

and the relevant xmp:
DSC04603.ARW.xmp (19,3 KB)

[kofa (István Kovács)]

Here it is: just an additional local contrast using a preset I had saved years ago.
DSC04603.ARW.xmp (14.5 KB)

So yes, it’s possible to bring more detail to the sky using a simple edit. Whether it benefits the image, is doubtful.

[Terry (Terry Pinfold)]

@g-man

The image processing start before you press the buttons on the camera. If the sky is the important part, then compose to the sky and select the aperture/speed for the sky.

This is so true. I feel you should expose for the highlights so they are not blown out and take care of the shadows later in processing. It is really a big ask of any editing program to faithfully recreate blown out highlights. The new inpaint opposed highlights recovery method does go a long way towards this. Recovering shadows is relatively easy, but the caveat is noise in those areas will be increased. Again DT tends to handle this well. With the denoise (profiled) module the preserve shadows slider is amazing with shadow noise.

In this image the lady carries an umbrella so maybe the overcast sky adds to the story of rain in the scene, but I would not want too much emphasis on the sky in this image.