Now I have the Ultimaker for over a year and have only the 0.4 mm nozzle used so far.
Time to try out the 0.23 mm nozzle ...
First tries with Nikola Tesla, Mario and the 0.23 mm nozzle.
Some more Nikola Tesla in 0.23mm...
... and with the 0.4mm nozzle (left: raw PLA, right: painted)
A Bitcoin and a Pirates of the Caribbean Medallion - both painted and printed using the 0.23mm nozzle.
I am Groot! Painted and using the 0.4mm nozzle.