[Cin] Trying to understand colour, try N!

Terje J. Hanssen terjejhanssen at gmail.com
Wed Nov 29 16:20:27 CET 2023

Den 07.11.2023 16:32, skrev Andrew Randrianasulu:

> вт, 7 нояб. 2023 г., 18:13 Andrew Randrianasulu <randrianasulu at gmail.com  <https://lists.cinelerra-gg.org/mailman/listinfo/cin>>:
> >//>/https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynamic-range-in-cycles-to-produce-photorealistic-looking-im 
> />//>//>/well, this one says EXR can hold quite a big value per channel, way 
> above />/1.0f, obviously. But for displaying (and encoding?) it must be 
> compressed />/back to device-specific 0 - 1.0 range. />//>/Thing is, if I open exr example file in gimp 2.10 and re-export it - it />/retain its above 100% values. It does not do this if I do this same />/roundtrip via cingg. So yea, we seems to be clamping at output. />//
> and this article about Premiere tries to explain Scopes, and especially
> floating point vs 8bit input - Premiere apparently can limit this setting
> for scopes themselves....
> https://blog.frame.io/2017/09/27/introduction-to-video-scopes/

By looking through the mail archive this month, I will just shortly add a user comment to the images in the latter url:
(I hope it will fit not too badly into the exiting mail thread)

  * Figure 1. Waveform Scope for an under-exposed shot
  * Figure 2. Waveform Scope after the shot is corrected

Fig. 1 is a typical dark shot in low-light or backlight conditions. I have also experienced similar results after digitizing analog SD video, apparently due to relative low color resolution.

Fig. 2 is the brighter, shiny video or shot result we normally want.


To compare with my smartphone (Pixel 7 Pro), I use "Night Mode" (with AI I think) to lighten up during shooting, or by editing photos with the dynamic or enhance tool.

> so, HDR as used in ultra HD need some scope that goes to 10.000 (so,
> logarithmic I guess ...)!
> something we should write somewhere in TODO, I guess .....
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