A new paper is out this week in Phys. Chem. Chem. Phys. Building on our previous work to resolve the structures of metal carboxylates in oil paint, we were now able to study the kinetics of metal soap crystallization in great detail. With this fundamental work, we are starting to understand why zinc and lead soaps behave so differently in paintings. Moreover, we may be able to use the structure of metal soaps as a marker for the conservation history of paintings and the internal chemical conditions of paint layers.