Saturation-clipping and Smoothadjust

[Katie Boundary]

The Harry Potter movies became increasingly dark and desaturated as they went on, as if directed by Zack Snyder. I'm not a big fan of that particular artistic decision, so I'm working on color-correcting them and I have a bit of a dilemma.

Smoothadjust is a godsend for fixing luma values. It allows for significantly increasing brightness and contrast in dark areas without having too much of a negative impact on the rest of an image. When it comes to saturation, however, it only has a flat multiplier like tweak(). Ergo, if I use it to increase saturation, I run the risk of sat-values getting "clipped" in high-sat areas, resulting in a flat, cartoony appearance. What I need is something more akin to smoothcurve(saturation="0-0;127-191;255-255")

Suggestions?

[Arx1meD]

Somehow I needed to change the darkened areas of the frame and wrote a script for this. This script chang the luma channel only, the saturation does not change. Maybe it will help you - Brightness (https://forum.doom9.org/showthread.php?t=182411).

[Selur]

(personally, I prefer to keep the color grading the way it was intended of the other, but ..)
depending on how extreme you want to get Retinex+Grayworld can to funky stuff: https://imgsli.com/MTU1MzEz https://imgsli.com/MTU1MzIx
Both were ported to Avisynth: https://github.com/Asd-g

Cu Selur

[Katie Boundary]

Never mind. It turns out that what I want can be accomplished with S-curves in the U and V planes in Smoothadjust.

In the process of trying to get the colors right, I'm also learning a lot about how YUV colorspace and the human visual system work. For example, there are HUGE differences between real contrast and apparent contrast, and between apparent saturation and real saturation. Apparent contrast in bright areas can be improved by darkening them even when real contrast gets crushed in the process. For example, if I were to take the 192-255 luma range and crush it down to 192-224, I'd lose literally half of the real luma detail in that range, but those details would become more visible to the human eye. Additionally, as an image becomes brighter (at least within a certain range), apparent saturation decreases even as real saturation stays the same.

[kedautinh12]

(personally, I prefer to keep the color grading the way it was intended of the other, but ..)
depending on how extreme you want to get Retinex+Grayworld can to funky stuff: https://imgsli.com/MTU1MzEz https://imgsli.com/MTU1MzIx
Both were ported to Avisynth: https://github.com/Asd-g

Cu Selur

Can you share your scripts??

Cu Kedautinh12

[Selur]

Didn't keep the script + I used Vapoursynth, but it was basically just loading the source, cropping (always crop !all! black bars before applying Retinex), applying Retinex(fulls=false, fulld=false) and then Grayworld.
+ I added some denoising after that to remove some of the upcoming noise.
Might have used SCUNet for the denoising, which is not available for Avisynth, but no special tuning or anything in regard of the color adjustments.

Cu Selur

[coolgit]

Fanedit JJPotter did all the Harry Potters movies and made some colour corrections. I loved the colours in the first 2 films under Chris Columbus direction, after that the directors when loopy darky depressing colours.(LDDC)

I used primarily smoothlevels, smoothtweak and ShiftCCT() from https://forum.doom9.org/showthread.php?t=168062 download _AWB_131201.txt and obviously change it to .avsi. I think I also used 6-axis colour from Vdub2 too in certain scenes.

I was able to somewhat match the colours of LDDC films to the first film. Not in every scene thought. But miles better than LDDC.

[Katie Boundary]

Fanedit JJPotter did all the Harry Potters movies and made some colour corrections. I loved the colours in the first 2 films under Chris Columbus direction, after that the directors when loopy darky depressing colours.

Haha yeah...

https://i.imgur.com/XaNaaCA.jpg