1
\$\begingroup\$

I've been using RawTherapee (and then its fork, ART) for several months, and overall I have been quite satisfied with it. However, there are a handful of scenarios where I'm struggling to achieve the results I'm looking for. Usually I've seen this on photos where there is a strong, vibrant orange present - such as a sunset or a fire.

I've attached a sample of what I mean. In the embedded JPEG, the color transitions fairly smoothly from a bright yellow in the center of the fire to a saturated orange toward the top of the flames. In the "straight-outta-ART" image, there are some clear bands present, the colors doen't transition smoothly, and there is a reddish cast present in some of these "banded" areas.

Obviously there's a way to get from the input RAW file to the embedded JPEG file, and I'd like to use that (or something very close) as a starting point for my edits. Is this just "Canon processing magic", or are there tools/techniques I should look into to try to match these? I tried comparing the relative color levels at a few points, and adjusting white balance and individual RAW black point levels for each channel, but I wasn't able to get anything close to the embedded JPEG.

Here's the embedded JPEG (scaled for file size limits): Embedded JPEG, scaled down for web

...and here's the straight-outta-ART image (again, scaled down for file size limits): enter image description here

...and here's a link to the original .CR2 file: https://www.anthonymapes.com/2021-12-21/

\$\endgroup\$
8
  • \$\begingroup\$ What internal color space are you using with ART? \$\endgroup\$
    – Michael C
    Commented Dec 22, 2021 at 0:45
  • 2
    \$\begingroup\$ Just to note: Photoshop doesn't get it right either, though it's a lot closer & you can just about force it. I'd trot out my usual 'why not just use the camera manufacturer's app?' but I can't find one for Canon other than one designed to manage your entire life. \$\endgroup\$
    – Tetsujin
    Commented Dec 22, 2021 at 11:32
  • \$\begingroup\$ @MichaelC I'm using the default, which has the "Working Profile" as "ProPhoto" and the "Output Profile" as "RTv4_sRGB" \$\endgroup\$
    – maples
    Commented Dec 23, 2021 at 1:32
  • \$\begingroup\$ @Tetsujin Canon's DPP has never tried to manage any part of my life. Whatever are you talking about? \$\endgroup\$
    – Michael C
    Commented Dec 24, 2021 at 9:36
  • \$\begingroup\$ @MichaelC - I tried finding a simple photo processing app on Canon's site. Best I could find was something that wanted to import my photos from everywhere & post them to farcebork. DPP wasn't listed in their 'software' section. I don't use Canon, so I was approaching it like any punter with no link & just the power of google. So now we've found one, I'm now back to my usual "Why not just use the camera manufacturer's app?" \$\endgroup\$
    – Tetsujin
    Commented Dec 24, 2021 at 10:07

1 Answer 1

2
\$\begingroup\$

Using Canon's Digital Photo Professional 4 to open your raw file, it seems your camera used the Standard picture style, a White Balance setting of around 3800K, no tint corrections, and a fairly neutral contrast curve (neither high contrast nor low contrast). The only lens correction was for 'Peripheral illumination' set at 70%.

Any attempt to flatten the highlights or boost the shadows will very quickly result in the banding you're seeing in your example above. It looks like you tried to compress the dynamic range with ART and that's what caused such severe banding.

There are a few areas where the highlights are blown, but any brute force attempt to pull them back will result in the mid highs also being flattened, and that's the major source of your banding. Pulling exposure/brightness back requires a 2/3 stop adjustment to eliminate the brightest highlights from blowing out.

Here's what I got with Canon's DPP 4 using the default in-camera settings except for changing WB from 'Auto - ambience priority' to '3800K'.

enter image description here

By pushing brightness by 1/6 stop, changing the WB to 4600K with a slight tint towards magenta, crushing the shadows just a bit (to deal with a little noise in the very dark shadows, reducing contrast very slightly, and using the HSL tool to adjust individual colors (more on that below), I got the following result.

enter image description here

I also applied lens correction at the default settings for CA, color blur, and distortion.

Here are screenshots of the two key tabs in Canon's Digital Photo Professional 4 with the adjustments I used.

enter image description hereenter image description here

The HSL adjustments in the red, orange, and yellow bands pulled the red and yellow areas towards orange, which is the predominant color in the photo. This smoothed the transitions between each color band. There is virtually no green, aqua, blue, purple, or magenta in the image, so we made no adjustments at all to those color bands. By reducing overall saturation on the first tab and then pushing it in the HSL tool, it made the effects of the individual color channel adjustments stronger.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.