Timeline for Which luminous efficacy function does BIPM reference?
Current License: CC BY-SA 4.0
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| Nov 8, 2019 at 21:32 | comment | added | Ruslan | I actually meant that $\S4.5$ of MEP 2019 defines that, for instance, "If the luminous efficiency function used is not specified, it is assumed to be the $V(\lambda)$ function.". And $V(\lambda)$ is the photopic luminosity function defined in Table 1 of the same reference. So 10 lm means, unless specified differently, the value one would obtain from a spectral power distribution with the spectral weight function given in Table 1 of MEP 2019 — not only the value for 540 THz monochromatic light. | |
| Nov 8, 2019 at 21:01 | comment | added | Michael Deckers | You are right, 10 lm means something for 540 THz; but what it means for other frequencies is not defined by the SI system. Nor should it be, in my opinion. There is a similar case for the sievert: in this case, the SI system does not even give a reference for any radiation with quality factor 1 Sv/Gy; the choice of quality factors just is not a matter of the unit definition. Thanks for your proposal! I added photometric references as in the SI Brochure -- I hope that is what you meant. | |
| Nov 8, 2019 at 20:53 | history | edited | Michael Deckers | CC BY-SA 4.0 |
edits suggested by Ruslan
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| Nov 8, 2019 at 17:27 | comment | added | Ruslan | Actually the rules appear to be more specific, as given in clause 4.5 of your link. Moreover, they even provide tables of the luminosity functions, which is actually what I was looking for. So it's not as bad as "10 lm means nothing until you tell your luminosity function". It would be nice if you edited your answer to include these rules from 4.5, or at least mention them. | |
| Nov 8, 2019 at 17:27 | history | edited | Ruslan | CC BY-SA 4.0 |
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| Nov 8, 2019 at 14:45 | review | Late answers | |||
| Nov 8, 2019 at 15:15 | |||||
| Nov 8, 2019 at 14:30 | review | First posts | |||
| Nov 8, 2019 at 14:37 | |||||
| Nov 8, 2019 at 14:29 | history | answered | Michael Deckers | CC BY-SA 4.0 |