A buffer used with a Z-buffer to hold information concerning the visible transparent surfaces to be considered at each pixel of an image. The A-buffer originated in an anti-aliasing hidden-surface removal algorithm developed by Loren Carpenter around 1984. It resolves visibility among an arbitrary collection of opaque, transparent, and intersecting objects. The algorithm was developed for the REYES system at Lucasfilm Ltd. Road to Point Reyes was a famous image produced by the system.