Optical Printer Applications Language (OPAL) embodies a new computer operating system which simplifies the difficult and time-consuming task of optical printer operation. Developed by a team at J-K Camera Engineering, it provides flexible automatic control of camera and projector sequencing, X-Y lens positioning, follow focus, zooms, pans, fades, bellows extension exposure compensation, and color balance adjustments. On complex optical printing jobs, job completion speed is increased considerably, up to a factor of ten or more over a manually operated machine. The OPAL system converses with the operator via a standard video terminal in plain English; no prior programming training or computer experience is required. The system was developed to control the Model 120-C optical printer, which was specifically designed to be controlled by a computer. The need for electronic and mechanical control systems has been eliminated, simplifying the optical printer design, and improving reliability with a reduction in costs. OPAL will adapt to most microcomputers which use the 8080-Z80 instruction set and the S-100 bus. It is written in machine code and is independent of any external software. It contains its own motor driven programs, timers, video driver, mathematics subprogram library, etc. Operation is easy and straightforward. Most commands are entered as answers to questions asked by the system on the video terminal. Complex printing tasks, such as accelerating zooms and pans, and linear or logarithmic fades, can be rapidly performed by operators having little training and experience. The system is expandable and can be adapted to control other equipment, such as animation stands.