Electromagnetic radiation sensitive mask materials are provided. The mask materials are chosen such a first percentage of electromagnetic radiation at a first wavelength is transmitted through the mask material prior to the exposure of the mask material to electromagnetic radiation at a second wavelength and a second percentage of electromagnetic radiation at the first wavelength is transmitted through at least a portion of the mask material after the at least a portion of the mask material is exposed to electromagnetic radiation at the second wavelength. Methods of patterning substrates using electromagnetic radiation sensitive mask materials are also provided. Compositions for producing masks are provided, and systems are provided.