A phase and amplitude, off-axis hologram has been synthesized from three computer-generated masks, using a multiple exposure technique. Each of the masks controls one fixed phase cothpOnent'of the Complex hologram transmittance. The basic grating is generated optically, relieving the computer of the burden of drawing details the size of each fringe. The maximum information capacity of the computer plotting device can then be ap-plied to the generation of the grating modu-lation function. With this arrangement large holograms (25mm'X'25mm) have been synthesized in dichromated gelatin.