The x-ray image formed by total-external reflection from a concave spherical or cylindrical surface is faulted by numerous geometrical aberrations. Unfortunately the "blur" recorded on the film does not separate out the individual aberrations or reveal the controlling system parameters. Ray tracing with the aid of a high speed computer may aid in identifying a prominent type of aberration but will not in general yield the functional dependence of the system parameters on the blur. The present analysis develops a theo-retical expression for the blur as a power series in which the individual terms may be identified with well known aberrations defects. The coefficient of each term is expressed in terms of applicable system parameters and thus indicates almost at a glance what can be done to minimize a particular aberration. It is cautioned however that a favorable change in one aberration coefficient may cause an unfavorable change in another.