Some embodiments include methods of treating reticles to provide backside masking across regions of the reticle to compensate for problems occurring during photolithographic processing. The problems may be, for example, defects in the reticle, problems associated with deposition or development of photoresist, or problems associated with substrate topography. The masking may alter one or both of transmission of electromagnetic radiation through the masked regions, and polarization of electromagnetic radiation passed through the masked regions. Some embodiments include reticles having patterns along front sides for patterning electric magnetic radiation, and masks across portions of the backsides to at least partially block transmission of electromagnetic radiation through portions of the patterns.