Microcapsules including a color-filtering shell and a core comprising a leuco dye or dye precursor, a photoinitiator or photosensitizer, and a photohardenable or photosoftenable material are provided for use in microcapsule imaging sheets. The imaging sheets including such microcapsules reduce undesirable crosstalk among the microcapsules of various colors and provide significantly improved color fidelity of the image thus reproduced.

A PTSM-coated expandable microsphere comprises a polymer shell enclosing an interior volume containing at least one blowing agent. The polymer shell has an outer surface with photothermal susceptor material disposed on at least a portion thereof. If heated to at least one temperature greater than 25 C., each of the expandable microspheres expands, but does not rupture, the polymer shell by a sufficient amount to at least double the interior volume. A markable comprises a substrate and a viewable layer secured thereto. The viewable layer comprises a binder material retaining the PTSM-coated expandable microspheres. A method of marking a markable article comprises imagewise exposing the PTSM-coated expandable microspheres of the markable article to at least sufficient electromagnetic radiation to cause the PTSM-coated expandable microspheres to expand thereby creating a predetermined image. A marked article preparable according to the method is also disclosed.