darktable is an open source photography workflow application and raw developer:
https://www.darktable.org/
Free/Open Source Photography:
https://pixls.us/
Secrets of color-grading in photography by Joanna Kustra:
https://youtu.be/mC8ol2-V7Ck
0:00 Intro
1:15 Edit 1
18:54 Edit 2
31:13 Edit 3