Outer rings and pseudorings are features commonly observed in disk galaxies in the range of Hubble types S0+ to Sab (see, for example, de Vaucouleurs 1975). As part of a general program to study the nature of rings in disk galaxies, we have begun imaging a large sample of outer rings to study their morphological and photometric properties in detail. Our goal is to evaluate whether these rings are related to the outer Lindblad resonance (OLR), a major 2:1 resonance known to be important for ring formation in n-body models where dissipation in the gaseous component is significant (Schwarz 1981 = S81). The morphology of outer rings is important because S81 predicted that near the OLR two major families of periodic orbits can lead to formation of two morphologically distinct types of outer rings and pseudorings: one type elongated perpendicular to the bar with arms intersecting near the bar axis, and the other elongated parallel to the bar with arms intersecting 90° to the bar axis. These ring types were searched for on the SRC IIIa-J sky survey copy films by Buta (1986), who called them R'1 and R'2, respectively. The full results of Buta's SRC search, which includes other types of rings, is being prepared as the Catalogue of Southern Ringed Galaxies (Buta and Crocker, 1990 = CSRG) and its contents are discussed in Buta (1990, this conference).