Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: Redcrown on November 03, 2015, 12:26:32 am
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This is interesting. Guy uses a CD/DVD disk as a prism to show the spectrum of daylight vs. CFL vs. LED light sources. That part is the first 3 minutes. The rest is about wiring and not relevant.
Not sure what to think of it?
https://www.youtube.com/watch?v=EoAZ-u6hn6g
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This is interesting. Guy uses a CD/DVD disk as a prism to show the spectrum of daylight vs. CFL vs. LED light sources. That part is the first 3 minutes. The rest is about wiring and not relevant.
Not sure what to think of it?
Well, it give a good impression of how continuous the illuminant's spectrum looks to the human eye (color sensitivity imperfections included).
Cheers,
Bart
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As they used to say on Laugh in on TV: Very interesting but stupid ;D
If you want to examine the spectrum of an illuminant, use a Spectrophotometer and good software to plot it.
http://www.ppmag.com/reviews/200604_rodneycm.pdf (http://www.ppmag.com/reviews/200604_rodneycm.pdf)
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This is interesting. Guy uses a CD/DVD disk as a prism to show the spectrum of daylight vs. CFL vs. LED light sources.
I made a spectroscope using a cheap diffraction grating, a cardbox box and a ~50mm projector lens as a collimator:
(http://kronometric.org/phot/lighting/spectroscopy/LT130402/scope.jpg)
The grating - dirt cheap on eBay:
(http://kronometric.org/phot/lighting/spectroscopy/grating.jpg)
You shoot the grating with the lamp shining through the slit (two utility knife blades) at the other end (guess the type of lamp).
(http://kronometric.org/phot/lighting/spectroscopy/LT130402/IMGled.jpg)
The nearest WB to "equal energy" seems appropriate. On my Sigma DSLR these days I remove the hot mirror (easily done with the thumb nail!) to eliminate it's UV/IR blocking effect.
Then convert to TIFF and open in ImageJ to get a response graph.
Here is a comparison between an LED Flood Lamp lab test and the method describe above:
(http://kronometric.org/phot/lighting/spectroscopy/LT130402/lampLED.jpg)
(http://kronometric.org/phot/lighting/spectroscopy/LT130402/specCompLED5000K.jpg)
The blue was not as evident in shots as the peak would suggest but, based on the graph, I now use their 3500K model with great success.
Here's a CFL compared to a GE Halogen flood:
(http://kronometric.org/phot/lighting/spectroscopy/LT130402/HalCfl.jpg)
Hope this is of interest.
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Good job, Ted.
Jim
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Good job, Ted.
Thanks Jim, praise indeed!
I was beginning to think that I had posted a thread-stopper ;)
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Nice, love it :)