We don't need no stinking gamut limits!

A good challenge. Thanks!

Here’s my 2 cents, with pre-dev build (lacam16n2) RT 5.10-512-g6b35d3746
My aim was to flatten the dynamic range and make that ocean water a bit more appealing :slight_smile:

Kite Surfer.nef.pp3 (31.8 KB)

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You obviously know Wellington, if you can nominate individual bays! :saluting_face:
This is Lyall Bay, immediatley after my joyflight and time at Wellington International Airport where I also got to delight in the USAF Globemaster visit. WLG is sandwiched between Lyall Bay to the South and Evans Bay to the North.
Yes, it was a southerly breeze.

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That’s a negative (:stuck_out_tongue_winking_eye: ) - however there is significant foreshortening due to the telephoto effect. EXIF data gives a focus distance of just under 126 metres. I haven’t applied any lens-correction* and certainly no perspective correction, so what you observe may be down to imperfect optics.

  • There are two reasons I haven’t applied lens correction:
  1. I haven’t tweaked my custom settings since the most recent update of lensfun
  2. This lens usually has very limited need for correction, in my experience, so I haven’t bothered with 1 just yet.
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2024-04-06_17-09-46.72_DSC6190.nef.xmp (16.1 KB)



first version darktable and second version GIMP with posterization and cartoon filter

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The original raw converted with imagemagick and -clahe to a .png with -quality 05, then rotated to the correct orientation with darktable

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2024-04-06_17-09-46.72_DSC6190.nef.xmp (15.7 KB)

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ImageMagick’s -clahe converts the image to CIELab, operates on only the L channel, and converts back to the original colorspace. That’s fair enough.

We can get a more colourful output by applying -clahe to the RGB channels independently. Windows BAT syntax:

%DCRAW% -v -w -6 -O x.tiff 2024-04-06_17-09-46.72_DSC6190.nef

magick ^
  x.tiff ^
  -channel RGB ^
    -separate ^
    -clahe 10x10%%+1024+10 ^
  +channel ^
  -combine ^
  -quality 40 c.jpg

The -clahe parameters are:

  • 10x10% fairly small tiles, so the “high contrast” is very local.
  • 1024 bins for a fairly high precision
  • limit clipping to 10, a fairly high number for high local contrast. More usually this would be around 2.0 to 3.0.

The result c.jpg is:

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Seems like I’m rolling with the contrasty approach of the OP…


2024-04-06_17-09-46.72_DSC6190.nef.arp (14.3 KB)

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2024-04-06_17-09-46.72_DSC6190.nef.xmp (18.4 KB)

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2024-04-06_17-09-46.72_DSC6190.jpg.out.pp3 (14,3 KB)

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2024-04-06_17-09-46-88.jpg.out.arp (11.9 KB)

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2024-04-06_17-09-46.72_DSC6190.nef.xmp (17.2 KB)

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OK, I’m a total Noob to post-processing. Your rendering is fantastic. Can this ‘CLAHE’ be achieved in Raw Therapee? I’m searching for articles/tutorials. Thanks!

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I’m not sure if RT supports ctl but I bet it could be used to create this sort of application in ART…

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