
Measuring the Spectral Characteristics of a Light Therapy Lamp - jamesbowman
http://justinmklam.com/posts/2018/01/sad-lamp/
======
stedaniels
I'd love to see the something from Lumie [0] analysed/reviewed like this in
the UK. For instance the Lumie Vitamin L [1] is an LED version I'm interested
in getting. I suffer for terrible migraine with aura [2] verging on chronic
[3] that's started to beat my maximum dose of beta blockers, so I'll try
anything!

[0] [https://www.lumie.com/](https://www.lumie.com/)

[1] [https://www.amazon.co.uk/Lumie-Vitamin-Lightbox-Effective-
Th...](https://www.amazon.co.uk/Lumie-Vitamin-Lightbox-Effective-
Therapy/dp/B073P2WNDS/)

[2] [https://www.migrainetrust.org/about-migraine/types-of-
migrai...](https://www.migrainetrust.org/about-migraine/types-of-
migraine/migraine-with-aura/)

[3] [https://www.migrainetrust.org/about-migraine/types-of-
migrai...](https://www.migrainetrust.org/about-migraine/types-of-
migraine/chronic-migraine/)

~~~
clauraform
I suffered frequently from terrible migraine until a chiropracter worked my
spine. After that it was gone, except for one time months later. That was in
my teenage years following a growth spurt and neuroactive narcotics abuse. The
closest I got to feeling like that again was from too little sleep and work
out, coupled with too much coffee and cigarettes. I'm still luzzled how likely
blocked arteries figure into this. Still I get a numb hand from time to time.

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Y_Y
The conclusion about the UV diffuser isn't quite right. It clearly
preferentially attenuates around 365nm for example. Good article and solid
conclusion though.

~~~
joshvm
Really the absorption measurement should have been taken using a broadband
lamp (an old light bulb would do). Using a CFL, the signal to noise in the
attenuation region is pretty poor to begin with.

A lot of plastics (e.g. Polycarbonate) attenuate UV - you have to go out of
your way to find windows that will pass it. For example:
[http://www.randombio.com/clear-lucite-
spectra.png](http://www.randombio.com/clear-lucite-spectra.png)

------
smartbit
Can anyone tell how to measure the R1-R14 [0] values of a LED lamp? It seems
like a sort of a Gretag-Macbeth [1] card is used. Can I use a
photospectrometer [2]? I'd like to measure R9 [3] & R13 myself.

[0] [http://gc-lighting.com/led-education/lighting-guide/](http://gc-
lighting.com/led-education/lighting-guide/)

[1]
[https://en.wikipedia.org/wiki/ColorChecker](https://en.wikipedia.org/wiki/ColorChecker)

[2]
[https://en.wikipedia.org/wiki/Spectrophotometry](https://en.wikipedia.org/wiki/Spectrophotometry)

[3] [http://leapfroglighting.com/why-the-led-r9-value-isnt-
import...](http://leapfroglighting.com/why-the-led-r9-value-isnt-important/)

~~~
andreareina
There seems to be little overlap in the Munsell colors between the two[1][2].
There does appear to be a variant that uses some ColorChecker patches[3], or
there's another calculation that just goes directly off of the light's
emission spectrum[4], assuming your spectrometer has enough resolution. I
think in practice, an ad-hoc comparison of the ColorChecker under daylight/D65
and the light in question will yield good enough results.

[1]
[https://en.wikipedia.org/wiki/Color_rendering_index#Test_col...](https://en.wikipedia.org/wiki/Color_rendering_index#Test_color_samples)

[2]
[https://en.wikipedia.org/wiki/ColorChecker#Colors](https://en.wikipedia.org/wiki/ColorChecker#Colors)

[3]
[https://en.wikipedia.org/wiki/Color_rendering_index#New_test...](https://en.wikipedia.org/wiki/Color_rendering_index#New_test_color_samples)

[4]
[https://en.wikipedia.org/wiki/Color_rendering_index#Example](https://en.wikipedia.org/wiki/Color_rendering_index#Example)

------
nate_meurer
Oddly, the article neglects to mention the whole rationale for boosting the
blue light in these kinds of therapy lamps: blue light (wavelengths in the low
to mid 400 nm range) has the greatest effect on circadian rhythm.

Google "blue light circadian" for loads of data.

------
pmlnr
True(ish) sunlight lamps are freakin' expensive, no wonder 70$ is a scam.

------
giarc
"bone-chilling,.... Vancouver winter"

I guess temperature really is relative.

~~~
LeifCarrotson
It makes me wonder if there are geographic/climactic components to seasonal
affective disorder.

In Vancouver, it's going to be in the "bone-chilling" upper 40s today, while a
few degrees south near me it will be in the low 20s. A few degrees south means
that even though we have colder weather, we'll have more hours of brighter
sunlight. In England, further north than either of our locations, it will be
in the low 50s (those temperature ranges are 8, -6, and 11 degrees Celsius,
respectively).

Would more people suffer from SAD in more northern locations because there's
simply less sun, but they'll choose to live there because it's warm enough as
a result of proximity to ocean currents? Or would fewer people suffer from SAD
because they can spend more time outside where it's warmer?

~~~
TheCondor
There does seem to be some correlation. People in more southern places are
less likely to have the condition.

