A vertical corrugation in a diaphanous ring can give rise to brightness variations.
In this graphic representation, the diagonal lines (or arrows) correspond to lines of sight through the corrugated ring. The grayscale plot along the bottom shows the ring's total optical depth (a measure of opacity) and brightness as seen by the observer.
See PIA08325 for more details about the vertically corrugated structure in Saturn's D ring.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.