A positive working printing form precursor comprises a thermally imagable composition
which includes a hydroxyl group-containing polymer, for example a novolak resin.
The composition has a weight of less than 1.1 gm-2. It has been found
that using a low weight of the composition on the precursor improves the properties
of the precursor, in particular by rendering the sensitivity of the precursor to
imaging radiation less variable over time.
