Darktable is excellent at finding out what’s worth processing and what’s not worth processing. Darktable gives you the tools.
One of these tool is the Focus Peaking Mode. It works in both the Lighttable and the Darkroom.
Pressing “Ctrl-Shift-F” will enable the focus peaking mode.
The Focus Peaking mode uses a “heat map”
Focus Peaking in the Lighttable
Focus Peaking in the Darkroom
The yellow, green and blue …