How to *reasonably* emphasize crepuscular rays

2023-07-27_16-30-21.09_DSC6273.nef (20.8 MB)

On the same trip I went whale-watching (see here) I captured what to my eyes were very intense crepuscular rays. My camera thought them “meh.” Here is what I came up with using darktable to try to recreate what I saw. Boosting contrast made the foreground excessively dark, but my masking to prevent that also leaves artifacts, no matter how I fiddle with feathering. I’d be delighted to see what others can come up with.

This file is licensed Creative Commons — Attribution-NonCommercial-ShareAlike 4.0 International — CC BY-NC-SA 4.0

2023-07-27_16-30-21.09_DSC6273.nef.xmp (13.0 KB)


Not sure about my effort - I prefer yours overall! I used masked tone eq (x2, both on the same gradient mask) to lighten the foreground.
2023-07-27_16-30-21.09_DSC6273.nef.xmp (13.9 KB)

Edit: I loaded your xmp, and fiddled with the feather/blur for the foreground exposure mask, but found it tough to get right. Also didn’t like the halo the sharpen module was producing around the tree so swapped it for a more subtle application of D&S. And added a second instance of sigmoid for the foreground. Lot of fiddling for not much result TBH :sweat_smile:

2023-07-27_16-30-21.09_DSC6273_01.nef.xmp (22.5 KB)


A great exercise, thanks for sharing.
Here’s my version, I tried to play on the color contrast by warming up the foreground of the scene and accentuating the blue (cold) hues of the sky.
To avoid halos, I used 2 instances of the “tone equalizer” module.

2023-07-27_16-30-21.09_DSC6273.nef.xmp (36.0 KB)
Darktable master 4.5 & Sigmoid
Greetings from Brussels,


Would using a heavy bloom (using D&S preset and boosting greatly iterations and radius), then setting blend mode to multiply and playing with exposure fulcrum and opacity work? Sorry, not near computer to try this myself. @s7habo used this method in one of his videos to help create a glow in contrasts I think.

crepuscular-rays-2023-07-27_16-30-21.09_DSC6273.nef.xmp (14.7 KB)
dt 4.4.2


Thats a great pic to play with, thank you for sharing.

Here my try in RT 5.9-dev:

2023-07-27_16-30-21.09_DSC6273.nef.jpg.out.pp3 (15,3 KB)


A very quick play in GIMP. I really need to spend more time on it.

I’m on my phone now so I can’t try but I find low frequency local contrast can sometimes help with clouds and atmospheric details. Just have to be careful to avoid artifacts.

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My immediate response was “use a red filter on the lens”.

But we are in a digital world. Developing it simply with dcraw and examining pixel values confirmed my suspicion that the rays versus the sky show the greatest change in the red channel (red is about 38% in the rays, 32% in the background). So we can emphasise the rays by replacing the L channel of Lab by the red channel.

This gives a gentle change. We can also apply an S-curve to the lightness, increasing contrast at the middle grays at the expense of highlights and shadows.

This gives better detail in the sky, sea, and dark (tilting) horizon. We have lost detail in the foreground. This is no great loss, but maybe there is now too much dark at the bottom, and triming some off will restore balance.

(To me, this is a portrait of the sky and sea. The other elements – tree and foreshore – are merely supporting elements, to give shape to the sky and sea. The rocks are interesting, but raising them from shadows distracts too much, in my opinion.)

Windows BAT script:

%DCRAW% -v -T -6 -O x.tiff c:\web\im\2023-07-27_16-30-21.09_DSC6273.nef

magick ^
  x.tiff +write mpr:INP ^
  -colorspace Lab -separate ^
  -delete 0 ^
  ( mpr:INP ^
    -channel R -separate +channel ^
    -sigmoidal-contrast 8,35%% ^
  ) ^
  -insert 0 ^
  -combine ^
  -set colorspace Lab -colorspace sRGB ^
  -rotate -2 +repage ^
  -crop 5841x3575+141+249 +repage ^
  -resize 800 ^
  -quality 40 x1.jpg

I save a low-quality JPG for bandwidth reasons.


2023-07-27_16-30-21.09_DSC6273.nef.xmp (13.3 KB)


2023-07-27_16-30-21.09_DSC6273.nef.xmp (13.7 KB)


I often wonder on these things how much is an issue with the capture… either the camera or the settings and where our perception kicks in making our eyes see things more intense… I recall one time on my phone trying to catch a lovely orange harvest moon… It was an amazing color… I would take the shot and no color… I tried to drop exposure do whatever I could with the phone but I could not get that look captured… I think rainbows and some of these highlights are similar in this way… or maybe I am just misguided thinking this… maybe as some suggest its using auto WB when shooting that can mess up what gets captured??


I’ve just played around with the image to see if I can enhance the rays, rather than trying to do a full edit. The cursor in Tone Equalizer is showing that the strongest rays are only 0.1 EV brighter than the surrounding sky, so doing anything based on a curve is going to be tricky. Just for fun, I tried turning on Local Contrast and cranked the detail slider to 250%. It did enhance the rays, but made the rest of the image look like garbage. It might be worthwhile to use a mask to isolate the sky and then use LC on that masked area only…or Diffuse or Sharpen’s local contrast preset (didn’t try that because I’m on my laptop and I would still be waiting for the results).

BTW, the weaker rays in a couple of people’s edits looked a bit green.

Absolutely! Given an adequate amount of coffee, our eyes/brains are amazing!


How to reasonably emphasize crepuscular rays_2023-07-27_16-30-21.09_DSC6273.nef.xmp (14.3 KB)


Here is my black and white version with darktable.
Grain was added separately.

2023-07-27_16-30-21.09_DSC6273.nef.xmp (18.0 KB)


A second play in GIMP. This time I have gone for a darker rendition.


filmic with max contrast

Your “second play in GIMP” is may favorite edit, so far. Great job!


2023-07-27_16-30-21.09_DSC6273-4.jpg.out.pp3 (14,1 KB)

black and white has got my vote on this one. This was a tough one for me.

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