An imaging member is composed of a hydrophilic imaging layer having a hydrophilic heat-sensitive polymer containing heat-activatable thiosulfate groups, and optionally a photothermal conversion material. Upon application of energy that generates heat, such as from IR irradiation, the polymer is crosslinked and rendered more hydrophobic. The imaging layer is disposed on an interlayer on a support, which interlayer comprises a Group IVB element (such as titanium, hafnium or zirconium) compound for improved mechanical and imaging properties. The exposed imaging member can be contacted with a lithographic printing ink and used for printing with or without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads.