Article · Wikipedia archive · Last revised Jul 17, 2026

EULUMDAT

EULUMDAT is a data file format used for specification of photometric data especially intensity distributions from light sources such as lamps and luminaries. The file extension is .ldt. The format was proposed by Axel Stockmar in 1990. The format is the European equivalent to the IES file format specified in IESNA LM-63. The data in an EULUMDAT file is usually measured using a goniophotometer. The IES file format is more formally specified and many measuring instruments support both formats of file.

Last revised
Jul 17, 2026
Read time
≈ 1 min
Length
158 w
Citations
2
Source
EULUMDAT
Filename extension
.ldt
Developed byAxel Stockmar (Light Consult Inc.)
Initial release1990 (1990)
Latest release
2
1998 (1998)
Example of an EULUMDAT diagram, generated by the software QLumEdit 1.0.1 source ↗

EULUMDAT is a data file format used for specification of photometric data especially intensity distributions from light sources such as lamps and luminaries. The file extension is .ldt. The format was proposed by Axel Stockmar (Light Consult Inc., Berlin) in 1990. The format is the European equivalent to the IES file format specified in IESNA LM-63.1 The data in an EULUMDAT file is usually measured using a goniophotometer. The IES file format is more formally specified and many measuring instruments support both formats of file.

Software

EULUMDAT files can be read with Photometry.2

References

References

External links