Process for coating a substrate.

摘要

A substrate is coated with a visible light sensitive composition comprising a free radical addition polymerizable or cross linkable material and a photobleachable ionic dye-counter ion compound capable of absorbing visible light and generating free radicals. The composition is exposed to light to harden the composition, and to bleach the composition to an essentially colourless state. Also described are photohardenable compositions containing photobleachable ionic dye-counter ion compounds as photoinitiators useful in the aforesaid process.