A coffee spill leaves behind a dark stain around the puddle’s edge when it dries. But as drops of paint dry, some look like “fried eggs,” with “yolks” of color surrounded by pristine white halos, whereas others appear uniform. To understand this variability, researchers literally watched paint dry. They found that pigment concentration and temperature impacted how the liquid gelled and evaporated, information that could help control patterns in dried paint.
