Painter's Servant makes all cards the color of your choice. Mycosynth Lattice makes all cards colorless. What happens if they're both in play at the same time? Does the most recently played one take precedent?
The most recently played one takes precidence:
From the rulings on painter's servent:
In general continuous effects are applied in time stamp order (rule 613. Interaction of Continuous Effects). More info here: http://wizards.custhelp.com/app/answers/detail/a_id/1030