You are doing me a big favor by clicking the Like button :-)

Print with layer hight 0.05 mmm

Start with black
Change on 0.6 mm to white
Change on 0.8 mm to scin color
Change on 0.9 mm to pink
Change on 1.0 mm to red
Change on 1.1 mm to Black

Or use paint

In the slicer you can specify when filament change (see Prusa slic3r screenshot)