[Rockhounds] colour perception, organic fluorescence, etc

[Alan Goldstein]

I also noticed a difference in color between eyes. The sky was a different 
shade of blue between the left and right eye (slight but noticable). Haven't 
looked for the difference in years, need to try it again. As a long time 
amateur astronomer I always had fun comparing the subtle colors of stars and 
nebulae between different observers.

I also noticed the skyglow at night was different. If I observed with a red 
light, the night sky had a green color. If I looked with purple (from a bug 
light), the night sky had a deep red hue. Fun stuff! My observing buddies 
noticed the effect, so it wasn't just me. I was the one to point it out.

Poison sumac is a northern plant, not western. It is widespread in northern 
Indiana. Poison oak is the western plant.

Alan

----- Original Message ----- 
From: "J. R. Hodel" <jr50wv at yahoo.com>
To: <rockhounds at lists.drizzle.com>
Sent: Friday, December 12, 2008 9:11 PM
Subject: [Rockhounds] colour perception, organic fluorescence, etc


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





--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
---
-- 
_______________________________________________
Rockhounds at drizzle Mailing List
Subscription Services:
http://lists.drizzle.com/mailman/listinfo/rockhounds
List Home Page, with a link to the List Usage Policy:
http://www.eclecticlapidary.com/Rockhounds/index.html