This Research Note was originally published in CIE-Journal, Vol. 6, No. 1, 23-31, 1987.
In order to calculate the light striking a surface or leaving that surface from one or a group of man made and installed luminaires, it is necessary to know the light intensity distribution at all spherical angles from each luminaire that contributes light to that surface. The advent of personal micro-computers has made it possible for each technical person to perform his own calculations using a suitable application program. It is common practice to record the light intensity at a large number of spherical angles from a specific luminaire (photometric data set) onto magnetic media, such as a computer disk. While the standardization of the size, shape and other technical features between disks and computers has been done by others, it is necessary for the computer program reading data from the disk to know the sequence of data being transmitted about the luminaire, light source, and angles at which the data has been recorded. This is termed the "file format".

While many countries, and companies within countries, have already adopted a specific file format it is necessary to have an international file format so that the photometric data set specific to a particular country can be translated (by computer program) into the international file format; or that a photometric data set received in the international file format, can be translated (by computer program) into the specific file format used in a particular country or a specific application program developed by an individual or company.

The CIE Recommended File Format is not intended to be used for manual calculations to determine the specific light intensity at a specific angle, but rather to be easily read, without error, into a computer program, either for translation into another format, or for calculation of the results of a lighting installation.

The publication contains 28 pages, with 4 figures. It is readily availabe from the National Committees of the CIE or the CIE Central Bureau in Vienna.