A method of preparing negative-working, single-layer imageable elements improves their storage stability in a humid environment. The method includes enclosing the coated imageable elements in a water-impermeable sheet material that substantially inhibits the transfer of moisture to and from the imageable element. Such imageable elements include a radiation-sensitive composition that includes a radically polymerizable component, an initiator composition to provide radicals upon exposure to imaging radiation, a radiation absorbing compound, and a polymeric binder having poly(alkylene glycol) side chains.