The color wasn’t showing as you had no lights / not enough light in the scene…
the solid color strips were turned just enough that the light put them in the shadow…
Changed the camera view and added an HDRI, still has your point light…
with just the point light same camera view…
You might want to get yourself a copy of ABR-mate, I finally found a copy…HERE
It will convert .abr Brush-sets to PNG images…( Handy to get Adobe Photoshop .abr brush preset files into something that can be used outside of PS )
Discussion of using Transparent PNG as Brush in Blender…