I needed a case for an IOT device I created. I tried a “chocolate brown” woodfill (top in photo) then tried a Notcua brown PLA and although both were fine they both caught a color cast in the intended location.

In a first for me I applied a “kona” stain to the woodfill print using a simple brush. Didn’t bother with any prep but it turned out great and just what I wanted. The only special step was to use a paper towel to dab up excess stain since it naturally doesn’t sink in much.
#3Dprinting