The factors affecting image quality and X-ray sensitivity of ionography and xeroradiography were studied. The relative charge sensitivities (nC/cm2mR) were compared. High pressure Xe (10 atm cm) used in ionography produced more than 2.5-3.5 .times. more charge than the Se layers used in xeroradiography for the same X-ray exposure. The influence of development time and toner deposition on the appearance of images was investigated. A parameter describing development sensitivity is proposed. An increase in development sensitivity (ODcm2/nC) with increasing development time was accompanied by a loss in edge enhancement. The development sensitivity of ionography was about 2 .times. that typical of xeroradiography. This makes the total sensitivity (OD/mR) of the ionography process more than 4.5-6.5 .times. xeroradiography. The total sensitivity of ionography is about 1/2 that of par speed film screen combinations.