Flexographic element having an integral thermally bleachable mask layer

An imageable element useful as a flexographic printing plate precursor is disclosed. The element is made up of a flexible substrate; a photosensitive layer, which contains a negative working photosensitive composition; an optional barrier layer; and a masking layer. The masking layer is thermally bleachable, comprises a dye that typically has an absorption maximum between about 250 nm and about 600 nm, more typically between about 300 nm and about 500 nm, and is substantially free of photothermal conversion materials.