Abstract: A system for microfilming documents that employs microprocessor control to insure fault-free operation. The aspects of operation; such as document present, size of document, size of photographic mask, the exposure parameter, and system "ready", must meet necessary criteria, or the microprocessor will halt operations and present a human-readable response as to the cause.Substitutional tables for supporting documents are available, to relate to the characteristics of the document.Simultaneous conflicting commands are executed sequentially according to a priority sequence.