This is the fourth revision of this standard. Since its introduction in 1986 (IESNA LM-63-1986), this standard has proved to be very useful and powerful. This revision further clarifies the standard to make its use as simple as possible.

This document describes the ANSI/IESNA LM-63-2002 data system and how to build a file using this system. This recommended standard addresses photometric data file formats specifically for data transfer, however, it is recognized that this standard is often used for data storage and retrieval.