[Rockhounds] colour perception, organic fluorescence, etc

[J. R. Hodel]

HI Axel, Kitty, et al:

Someone remarked about color perception, and this not only varies between people but between eyes.  Now I'll date myself . . . Back in the day when I spent a lot of time in a darkroom and comparing color results from film batch to batch, and from video camera to video camera despite the best job the color engineers could do, I noticed that my eyes had slightly different color responses.  Partly this was noticable because back then you aimed a film camera with one eye at the viewfinder.

One eye was closer to Ektachrome and one was closer to Kodachrome - go figure.  It's less noticable now, but still there.  So comparing colors of phosphorescence and fluorescence with the naked eye and discussing it via email may be futile.  Surely the color business has sensors that make this all objective nowadays?

Axel, here in the North American forests we have several woods that fluoresce under the right stimulation.  Locust (I think the black locust variety native to the WV forest) glows, as does the shrub sumac.  This isn't the poison sumac which I think is a western shrub, this is a shrub which bears bright red fruit clusters with which you can make a pleasent non-intoxicating beverage.  It glows best in long-wave "black light".  I don't remember which spectrum locust responds to best.

Do we know what mechanism might cause the fluorescent reaction in organic materials?

Just wondering, sorry if we're off topic, but it is related to black light, etc.

Merry Christmas, everyone!

JR



      

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