Printing plate having printing layer with changeable affinity for printing fluid

A printing plate imageable by laser radiation consisting essentially of:

• a substrate having a principal surface comprising a material selected from the group consisting of aluminum alloy, steel, paper and plastic;
• and
• a printing member comprising an organophosphorous polymeric composition positioned directly on said principal surface, said printing member having an upper surface and a first layer underlying said upper surface, said first layer comprising said organophosphorous polymeric composition and a plurality of radiation-absorbing particles,
• wherein said upper surface is ablatable by imaging radiation to expose an underlying portion of said printing member and said underlying portion has an initial affinity for a priming liquid which is changeable to a different affinity for a printing liquid when said printing member is subjected to imaging radiation.