In an example of a three-dimensional (3D) printing method, a metallic build material is applied. A patterning fluid, including a metal salt, is selectively applied on at least a portion of the metallic build material. Prior to an application of additional build material, the metallic build material is exposed to light irradiation to cause the metal salt to reach a thermal decomposition temperature and thermally decompose to a metal. During the exposing, the metallic build material is maintained below a sintering temperature of the metallic build material.