The invention pertains to a method and apparatus for preparing a printing form from a precursor, particularly a method and apparatus for preparing the printing form by thermally treating a photosensitive precursor having a photopolymerizable layer. The method and apparatus includes heating the photosensitive precursor to a temperature sufficient to cause a portion of the layer to liquefy, contacting the precursor with a development medium to remove the liquefied material, and supporting a development medium with a core member adjacent an exterior surface of the photosensitive precursor, wherein a compressible collar of a closed-cell foam having a Poisson's ratio of less than 0.4 is disposed between the core member and the development medium.