Forum: Photography

Subject: May Challenge...a magic ball

TomDart opened this issue on May 20, 2005 ยท 13 posts

TomDart posted Fri, 20 May 2005 at 8:02 PM

This shows reflection, refraction but the color comes from diffraction of a sort. The magic ball is a bead of opal, about 12mm across. Inside this mysterious stuff are microscopic speheres of silica, spaced "just so" or then again "just so". The compactness and size of the miniature beads determines which color of light to reflect. That is how opal gems work, in the simple explanation. White light goes in and blue comes out..or red..or green..or yellow. Nature did a neat job with these gems.

TomDart posted Fri, 20 May 2005 at 8:03 PM

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DJB posted Fri, 20 May 2005 at 8:06 PM

Added to Challenge page
got_it.jpg

"The happiness of a man in this life does not consist in the absence but in the mastery of his passions."


L8RDAZE posted Fri, 20 May 2005 at 8:12 PM

Tom, Thats PRETTY cool! Hey... is OPAL translucent? Just wonderin how it would look backlit with an LED light?





TomDart posted Fri, 20 May 2005 at 8:53 PM

These images are for a piece of rough opal sold on eBay. The first is with normal light, showing the color play. The second is with light from below, showing that look. The reason for the second image on eBay was to show "no cracks" in the stone, something important to gem buyers. These gems may be put "underwater" and then using manual focus get a really good look. The water makes the uncut stone appear polished and the colors jump out. Just be sure there are no "cat hairs" floating in the water!

TomDart posted Fri, 20 May 2005 at 8:55 PM

Lit from below, a light shining through a hole in black cardboard.

tibet2004uk posted Fri, 20 May 2005 at 10:02 PM

Oh wow!! Fascinating!! Such interesting infos here! Thx for sharing Tom!

randyrives posted Fri, 20 May 2005 at 11:37 PM

Love the 2nd shot with the light shinning through it.

tvernuccio posted Sat, 21 May 2005 at 12:24 AM

that's such a neat entry, Tom! It's another show and tell & I i love this! nice learning this stuff! Your other pictures are cool too! but you gotta tell me...how'd ya get that opal to stay on that pointy thing...whatever it is? LOL! Sorry...just can't figure out what it is and how you got the opal to stay. you glue it? thanks for showing and telling!!!!! :) (i'm in a silly mood tonight. sorry guys!)

cynlee posted Sat, 21 May 2005 at 3:03 AM

beautiful opal gem shot in the color & clarity tom!! have a few of them... very fragile... here you had a challenge subject right at your fingertips all along :]

Tedz posted Sat, 21 May 2005 at 1:05 PM

Top Shot Tom d'Art...I used to dig for Opals....in Coober Pedy Australia...but failed to find My Fortune :]

jimry posted Sat, 21 May 2005 at 6:42 PM

cool shots indeedy...wonder if nature will work for me!

coolj001 posted Mon, 23 May 2005 at 5:08 AM

Cool photo and fascinating about the opal. I also like that last one w/the light shining through the bottom. -Jeff :-)