Abstract: Provided is a dielectric imaging sheet useful in electrographic imaging, wherein a particulate solid incorporated into the dielectric coating has been treated with an acyloxy or amino terminated polysiloxane. Short-chain polysiloxanes, e.g., 3 to 8 siloxane units, are preferred as the treating agent, with the amino group being preferably lower alkyl substituted and the acyloxy group being preferably lower acyloxy. Use of the specially treated particulate solid reduces moisture induced imaging defects upon using the dielectric sheet in electrographic imaging.