The architectural lighting community has long relied on standardized file formats for the electronic transfer of photometric data and related information. There is, however, also a need to distribute spectral data. Such data is pertinent, but not limited to, the spectral radiant flux of lamps and other light sources, the spectral transmittance of color filters, and the spectral reflectance of paint and other finishes. This data may be obtained when testing a light source, luminaire or material and may then be used in lighting application software, rendering software, analysis software or optical design software.

Generally the document will contain a single spectral power distribution. The data is formatted in accordance with W3C Extensible Markup Language (XML) 1.1 Recommendation and the W3C XML Schema Definition Language (XSD). This allows end users to utilize and view the data directly without the need for proprietary software.