Partial cure of UV inks during printing

A printing system comprising:

• a media transport system configured to transport a web of print media through a printing zone at a transport speed in a transport direction;
• a plurality of printheads each at least partially spanning the print zone and each configured to eject a radiation-curable ink;
• a plurality of PIN units each positioned after one of the printheads relative to the transport direction and each configured to partially cure the radiation curable ink;
• a controller configured to control a radiative power level of each PIN unit according to the transport speed thereby defining a nonlinear radiative power versus transport curve that has a minimum in the curve at a transport speed that is intermediate to a range of permissible transport speeds.