Imageable element and waterless printing plate

An imageable element comprising:

• (A) a substrate;
• and
• (B) a radiation sensitive imageable composition applied on the substrate comprising:
• (a) a first layer, comprising:
• (i) a photosensitive composition which undergoes a decrease in solubility in a developer upon absorption of actinic radiation by the first layer, in which the photosensitive composition of the first layer comprises a condensate of an aryldiazonium salt or a mixture of aryldiazonium salts with a condensable compound, and
• (ii) an inhibitor which is activated by heat or radiation of longer wavelength than the actinic radiation to retard the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation, wherein the inhibitor is present in an amount equal to or greater than 1% by weight of the first layer, and
• (b) a second layer contiguous to the first layer comprising an ink repellent polymeric material which is transparent to both the actinic radiation and the longer wavelength radiation.

An imageable element comprising:

• (A) a substrate;
• and
• (B) a radiation sensitive imageable composition applied on the substrate comprising:
• (a) a first layer, comprising:
• (i) a photosensitive composition which undergoes a decrease in solubility in a developer upon absorption of actinic radiation by the first layer;
• (ii) an inhibitor which retards the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation, in which the inhibitor is deactivated by heat or radiation of longer wavelength than the actinic radiation, such that the inhibitor upon deactivation does not retard the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation;
• and
• (b) a second layer contiguous to the first layer comprising an ink repellent polymeric material which is transparent to both the actinic radiation and the longer wavelength radiation.

A method of forming an image on a substrate comprising:

• (a) providing a substrate;
• (b) applying on the substrate a first layer of a radiation sensitive imageable composition comprising:
• (i) a photosensitive composition which undergoes a decrease in solubility in a developer upon absorption of actinic radiation by the first layer;
• and
• (ii) an inhibitor which is activated by heat or radiation of longer wavelength than the actinic radiation to retard the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation;
• (c) applying on the first layer a second layer of a radiation sensitive imageable composition contiguous to the first layer comprising an ink repellent polymeric material which is transparent to both the actinic radiation and the longer wavelength radiation, thereby forming an imageable element;
• (d) imagewise exposing the imageable element to heat or radiation of longer wavelength than actinic radiation;
• (e) thereafter exposing the imageable element to actinic radiation;
• and
• (f) developing the imageable element.

A method of forming an image on a substrate comprising:

• (a) providing a substrate;
• (b) applying on the substrate a first layer of a radiation sensitive imageable composition comprising:
• (i) a photosensitive composition which undergoes a decrease in solubility in a developer upon absorption of actinic radiation by the first layer;
• and
• (ii) an inhibitor which retards the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation, in which the inhibitor is deactivated by heat or radiation of longer wavelength than the actinic radiation, such that the inhibitor upon deactivation does not retard the decrease in solubility of the photosensitive composition of the first layer upon absorption of actinic radiation;
• and
• (c) applying on the first layer a second layer of a radiation sensitive imageable composition contiguous to the first layer comprising an ink repellent polymeric material which is transparent to both the actinic radiation and the longer wavelength radiation, thereby forming an imageable element;
• (d) imagewise exposing the imageable element to heat or radiation of longer wavelength than actinic radiation;
• (e) thereafter exposing the imageable element to actinic radiation;
• and
• (f) developing the imageable element.