What is your technique to greatly darken the sky?


(Carmelo Dr Raw) #21

I think this is a typical case where there is no 1-click solution… you have to work locally with luminosity masks to darken the sky while keeping the transitions halo-free.

This is what I could achieve with photoflow, using three separate masks for the building and the left/right trees:

DSC_0925.pfi (109.9 KB)

(Alberto) #22

I’m kind of late, but since I haven’t seen many attempts with RT, I thought I’d share mine, so here it is.

Here is also the pp3 in case someone is interested, though it uses one tool that is not in dev yet (called softlight). Without it, you get a picture with slightly less “pop” (but not a big deal)
DSC_0925.NEF.pp3 (10.7 KB)

(Thomas) #23

That’s because the thread was posted in “Processing/darktable”. Nice to see an RT version, too :slight_smile: .

(Alberto) #24

Doh! :man_facepalming: my bad, sorry for the noise, I totally missed the darktable tag…

(Thomas) #25

Don’t worry. I also post darktable edits under the RT tag :flushed:.


I know this is not the answer you’re looking for but I have recently found out about polarization filters and have found they really help with outdoor photography. It will clearly not help with that picture since it was already taken, but I have been impressed with the results straight out of camera with some of the shots I’ve made. Night and day, really: beats spending hours figuring out masks and filters in post-prod, in my opinion.

It does mean carrying around an extra thing and swapping that thing in and out, which is annoying, but I really like the results, so I thought I would share my experience here.

(Alberto) #27

that’s interesting indeed. my experience is very different, I haven’t been very impressed in fact. but it’s very possible that either I’m using them wrong, or I just got a too cheap one… can you post some example photos of their effect?

(Morgan Hardwood) #28

Polarizing filters can be helpful, and their effect cannot be replicated well in post-processing. However, a polarizing filter would not help in this church scene as the light is diffuse, and they require directional light to function, with the maximum effect at 90° from the source.

They’re usually used to:

  • Remove reflections from water, allowing you to see into the water (cannot be replicated at all in post-proc).
  • To darken the sky.
  • To remove “sky white” light reflected off of foliage to bring out more color.

Here’s an example from the woods from a few days ago.
No polarizer:
With polarizer:

It cut out the harsh light reflected from the foliage, which lowered the dynamic range of the scene a bit. The moss looks less sky-white and more its natural color - a strong green tinted yellow by the setting sun. Whatever bits of sky are visible are darker when using the polarizer as here I was about 90° to the sun.


Here is an example I did recently…

This first picture was taken with the polarizing filter:

Here’s the same shot with the filter removed:

Obviously it’s totally overexposed, because the filter removes a few stops itself… I did some corrections in-camera, which gives this result:

Now maybe I’m cheating because the filter messes around with exposure, but I genuinely think the results are much better with the filter for such scenes.

(Roel) #30

This is a weird comparison. Your shot without the filter does not seem properly metered at all. Did you put everything on manual mode to make the comparison with the polarizing filter? If so, it seems to me these images now only prove that the polarizing filter is not optically transparent.

If you have to opportunity, please take the shot again, but let the camera figure out the exposure and then see how that turns out. If you have a rotating polarizer, you might also want to try setting different angles and see how that changes the contrast in the sky.



I am not sure polarizing filters are supposed to be transparent: the whole point is to … er… filter the light that comes in. :slight_smile:

Unless you fly me back to Copenhagen, that will be difficult. But I can certainly relate future experiences here later…

It is a rotating polarizer and I did play around with those. Rotated back to “normal” gave similar “flooded” results.


And notice how the sky has a gradient in it? I suspect the filter is also not uniform either…

(Morgan Hardwood) #33

The filter is most effective at 90° to the light source, so it’s natural to see gradation, and is also one reason why you wouldn’t use a polarizing filter with a very wide-angle lens, especially when shooting 360° panoramas.

(Mica) #34

A circular polarizer is certainly not optically transparent and is not supposed to be.

(Morgan Hardwood) #35

More examples and explanations in Wikipedia:


The code for that is being worked on already. Together with exporting masks for use in GIMP later on. It’s still in an early state and might not work out in the end, so don’t hold your breath.

Darktable review in German online photo magazine

Ho yteaot,
Is enfuse a plugin for darktable?
Where can i find it or find a tutorial to learn to use it?



I am very late to this. I just used the zone system in dt to darken the sky, and then local contrast to sharpen. I could have darken it a bit more using highlights and shadows. But this is a quick edit that took less then 30 sec. I started using zone system and it works most of the time.


No “technical” treatment can make a good image with so an ugly light !