Change one color of a 2 color picture

[Krikor]

(03-12-2020, 08:10 AM)Ofnuts Wrote: Plenty of ways. If your dial has black markings on a white background(*), you can use a paint tool in "Lighten only" mode. Since it paints only if it makes the pixels lighter, and that any color is lighter than black but darker than white, it only applies color to the markings
(*) If necessary you can use "Colors>Brightness contrast" to make the dark parts darker and the light parts lighter.

Following the tip above Ofnuts, and considering that the background is black and the markers are white, I just changed it to Dark Only in brush mode.
       
Markers 2, 9, 10 and 11 colored in color c9b359