A thermal negative type presensitized plate provided with an image recording
layer
hardened by infrared rays on an aluminum support, wherein the aluminum support
has on the surface thereof, a grain shape with a structure in which a grained structure
with medium undulation with a specified aperture diameter and a grained structure
with small undulation with a specified aperture diameter are superimposed. For
the presensitized plate, contact characteristics between the image recording layer
and the support and scum resistance on a non-image area are kept compatible with
each other at a high level, a thermal diffusion depression effect by which an energy
generated by exposure can be efficiently used to form an image is excellent, and
sensitivity is high.