link between einstein and lux

Harald Teicher hteicher at biobase.dk
Fri Dec 22 05:17:05 EST 1995


Tony Travis (ajt at rri.sari.ac.uk) wrote:
: Harald Teicher wrote:
: > 
: > Sonia Amorosi (sonia at eagle.bio.unipr.it) wrote:
: > : Hello.
: > : Could anybody tell us which is the correlation between lux and einstein?
: > : Thank you very much
: > 
: > try these
: > 
: > conversion factors, k_lux to u_mol m_2 s_1
: > [...]

: The lux is a standard of 'brightness' or illumination in terms of its
: visual effect (as determined by 100 pairs of standard American eyes
: apparently) and is used by architects.  Lux meters were produced to
: measure the illumination level in buildings objectively, but the
: standard is based on a subjective impression of brightness and is not
: compatible with measurements in terms of the Einstein unit:

: 	quantum flux density = micro einstein / m2 / s 

: A lux meter is most likely to be a radiometer:

: 	1 lux = 1 lumen / m2
: 	1 lumen at 555nm = 1.47 mW

: 	Tony.
: -- 
: Dr. A.J.Travis,                       |  mailto:ajt at rri.sari.ac.uk
: Rowett Research Institute,            |
: http://www.rri.sari.ac.uk/~ajt
: Greenburn Road, Bucksburn,            |   phone:+44 (0)1224 712751
: Aberdeen AB2 9SB, Scotland, UK.       |     fax:+44 (0)1224 716687

i agree with you there, but at the end of the day we still need to have
at least an idea of the light _intensity_ . at least when reading articles it
is important to be able to have a rough picture of conditions, even though
they are painted with a broad brush


so, let me start the ball rolling
by giving some comparisons (northern european, spring, conditions)

20 uE.m-2.s-1 : sundown on a rainy day
200 dito   : rainy midday
400-100 ditto : cloudy midday
1200-1500 ditto: sunny midday

these are values i have measured personally....now, who can supplement these
with some lux values



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