Abstract. During its 13th meeting in 1994 the Consultative Committee for Photometry and Radiometry (CCPR) decided to carry out a comparison of luminous responsivity to be organized by the BIPM. This comparison was classified as a key comparison by the 14th CCPR in 1997 and subsequently named CCPR-K3.b.

Fifteen laboratories took part in this comparison by sending calibrated photometers to the BIPM. The photometers were compared with a common set of reference photometers to deduce the relative differences between the calibrations made in the participating laboratories.

In this report the details of the procedure and the results are presented.

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the Mutual Recognition Arrangement (MRA).