I started using RawTherapee two months ago and I was able to solve most issues I had while developing my RAW images. I now have an image that shows a red shimmer in some parts. Especially in the area marked by the blue rectangle:
This results in a peak in the red channel at the right side of the RAW file histogram:
The JPGs developed by the camera and by Darktable do not show the peak anymore.
Which tool(s) can I use in RawTherapee to achieve the same result?
Looks like you are clipping the Red channel:
Which leads to that spike and the slightly wonky colors/texture in the foreground. You can probably fix this with a combination of highlight reconstruction & correcting the exposure.
I’m not sure what you mean with the area you marked, but I’m pretty sure it’s not what’s causes the spike. In fact the spike is still there if you paint over that area in gimp.
Please let me know , what output profile you have chosen in the “CMS control in the Color tab”.
Please note the histogram shown ,is not that of raw file but that of the preview in the chosen output profile and this is what you get once you export your image and its not the histogram of raw file.
I had to leave before I could write an explanation. The spike is cause by data that goes from super-bright to clipped, and most of it is in the wall, not in the building in the background.
In this photo you’re dealing with the clipped white of the building in the background and the clipped wall lit by the sun. You want to recover the color and texture of the wall and for that highlight reconstruction using color propagation works best, but you also want the clipped white of the building to remain white - you don’t want the white paint to turn any other color. What works well for one does not work well for the other. My PP3 addresses both issues - it recovers the color and texture from the clipped wall using highlight reconstruction with color propagation, and uses Defringe to remove the colorization of the white wall (how did I know to use it? I zoomed in 1:1, noticed purple edges where there shouldn’t be any, and know that Defringe is designed to prevent that - know your tools, read RawPedia). Automatic raw chromatic aberration correction often prevents problems too.
Morgan, that was the kind of answer I was looking for. The text and the PP3 explain how to combine the right tools.
I had tried both Defringe and (manual) Chromatic Aberration Correction, but I wasn’t happy with both results. Lens Correction Profiles are not available for almost all MFT lenses. Hence, automatic raw chromatic aberration correction wasn’t an option.
You don’t need a lens correction profile for automatic ca correction in raw tab…
To explain, the auto CA correct actually measures the CA in the image and shifts the color planes in order to cancel it out. It handles non-symmetrical CA as well, which happens from image stabilization, tilt-shift lenses, or sometimes just the foreground or background can have a different lateral CA than the focal plane.
