Technical Fluorescence Question

[clammer]

Hello everyone. I''ve been lurking for some time, but a trip to a mall (why does everyone use maul??) store has prompted my first post. I''m looking to upgrade my e-ring and wanted to try on some different sizes. Anyway, I would like to first let everyone know that if a stone is certified then it is ideal cut. I know this is true because this is what they told me (um...since you don''t know me yet, I just want to let you know that was sarcasm)

I told him what I was interested in. About 1.8 carat, I/J color, SI2 but clean to the eye, faint to medium flurescence. He informed me that you can only see fluorescence under a blacklight. I told him that based on my research (reading PS) that fluorescence can make the diamond face up whiter. I couldn''t explain why this would be. So the question is why does the diamond face up whiter?

clammer

 

[WinkHPD]

Welcome! And thanks for the sarcasm, it sounds just like something last weeks shoe clerk would tell a client about the diamonds that he is learning about this week...

Fluorescence of a blue color will tend to mask a yellowish body color. In fact diamond dealers often use blue paper for the inside of their diamond packets as it tends to make a yellowish stone look whiter.

Wink

 

[blueroses]

Welcome! I''m not sure why PSers spell it "maul"--I mean, it''s obviously a joke and a dig at the mall stores, but I''m not sure what the exact reason is!

(Maybe b/c they maul your wallet with their inflated prices or maul your sense of logic with comments like what you were told?) Anyone?

 

[codex57]

Date: 3/17/2005 7:37

2 PM
Author: blueroses

(Maybe b/c they maul your wallet with their inflated prices or maul your sense of logic with comments like what you were told?) Anyone?

That''s why I spell it "maul." Cuz they maul you in pretty much every way possible. Even the fancy ones I''ve been too aren''t always that great (like Bailey, Banks, & Biddle and one Tiffany''s).

 

[joycer]

Hi clammer!

I can give you an answer, but I''m afraid it''s a bit technical. The short version is that in light rays Yellow and Blue are inverse colors and when they are combined your eye sees them as white. For those of you that want the long answer, here goes.

(In case you''re wondering where I''m getting this form, I have an IT background with some high level work in multimedia)
Your eye sees 3 main colors, Red Green and Blue (not red, yellow and blue), all others are some combination of them. Rays of light (like those that pass through a diamond) are direct light. Colours which you see in paints and dyes are reflected light, not direct light. So when you combine colors you''ll get different results with reflected light and direct light. This is why everyone thinks that blue and yellow makes green. That is true for paints (reflected), but not for rays (direct). For rays, the absence of color is black, and the combination of all colors is white. So if you want to turn yellow rays (like the ones passing through a diamond) white, you have to add the missing colours. On the image of the color wheel attached, a color in direct light is formed by combining adjacent ray colors. For example Cyan is equal parts green and blue, magenta is equal parts blue and red, and if you find yellow, you''ll see that it''s equal parts red and green. So a yellow diamond produces rays of equal parts red and green. The only color in the combination your eyes see that is missing is blue. So if we add equal part blue to the yellow (red and green combined) we get red, green and blue which forms every color combination for your eye, producing white rays!

Hope that helps!

 

[jenwill]

Joycer-

Thanks so much for that explanation! I did not know about the reflected light vs direct light color differences. Makes much sense, and I am saving this explanation of yours to my 'very interesting info' folder. Would you mind very much if I also posted it in the fluorescence folder in the glossary area?

 

[joycer]

Hi jenwill,

Thanks for the kind words. I''d be flattered if you used my posting! I''ve been lurking for a while and learned so much about diamonds that it''s nice to be able to give some knowledge back.

 

[clammer]

Wow. Thanks Joycer. I love learning the "why" something happens.

 

[glaucomflecken]

Date: 3/17/2005 8:21:37 PM
Author: joycer
Hi clammer!


I can give you an answer, but I''m afraid it''s a bit technical. The short version is that in light rays Yellow and Blue are inverse colors and when they are combined your eye sees them as white. For those of you that want the long answer, here goes.


(In case you''re wondering where I''m getting this form, I have an IT background with some high level work in multimedia)

Your eye sees 3 main colors, Red Green and Blue (not red, yellow and blue), all others are some combination of them. Rays of light (like those that pass through a diamond) are direct light. Colours which you see in paints and dyes are reflected light, not direct light. So when you combine colors you''ll get different results with reflected light and direct light. This is why everyone thinks that blue and yellow makes green. That is true for paints (reflected), but not for rays (direct). For rays, the absence of color is black, and the combination of all colors is white. So if you want to turn yellow rays (like the ones passing through a diamond) white, you have to add the missing colours. On the image of the color wheel attached, a color in direct light is formed by combining adjacent ray colors. For example Cyan is equal parts green and blue, magenta is equal parts blue and red, and if you find yellow, you''ll see that it''s equal parts red and green. So a yellow diamond produces rays of equal parts red and green. The only color in the combination your eyes see that is missing is blue. So if we add equal part blue to the yellow (red and green combined) we get red, green and blue which forms every color combination for your eye, producing white rays!


Hope that helps!

WOW This brings me back to my color vision class in optometry school!!! optics, light and the human eye are so neat (and so is how they all interact when it comes to diamonds

). Thanks for the post!!!

 

[IrishEyes]

Whoa! Joycer, good job!! I haven''t seen such an in-depth and technical explanation like that on here in awhile!!

Aren''t you the smarty-pants?!

 

[Garry H (Cut Nut)]

Great explanation Joycer.

I saved it too
Another way to look at it is the spectrum of a yellow thing has some of the blue missing (and vice a versa)

With I/J color I would prefer strong blue.

 

[cflutist]

Date: 3/17/2005 11:10:48 PM
Author: Garry H (Cut Nut)
Great explanation Joycer.

I saved it too
Another way to look at it is the spectrum of a yellow thing has some of the blue missing (and vice a versa)

With I/J color I would prefer strong blue.

Garry, now I am confused. Others have posted that a "J" faces up as white as can be. If that is the case, why would you prefer strong blue fluor in an I/J? Not having seen say a "J" next to an "E" myself, can you, in your expert opinion see a difference in color? Can any of the other GGs chime in here?

 

[Garry H (Cut Nut)]

it is not easy to see the difference between a .01 ct J and a D.

Everyone can see the difference between a 20ct D and a G.

J can face up white under halogen lights.
But turn it at 70 degrees away and look under daylight or fluorescent lighting or office type and everyone can see it in a 1ct stone.

 

[denverappraiser]

Date: 3/17/2005 6:46:17 PM
Author:clammer

(why does everyone use maul??)

clammer

Not everyone uses that term.

Some people have had bad experiences with some stores located in shopping malls and they expand that stereotype to include all stores in all malls wherever they may be. People use racial stereotypes for similar reasons.

Neil Beaty
GG(GIA) ISA NAJA
Independent Appraisals in Denver

 

[cflutist]

Date: 3/18/2005 6:42:54 AM
Author: Garry H (Cut Nut)
it is not easy to see the difference between a .01 ct J and a D.

Everyone can see the difference between a 20ct D and a G.

J can face up white under halogen lights.
But turn it at 70 degrees away and look under daylight or fluorescent lighting or office type and everyone can see it in a 1ct stone.

Garry, thank you for your explanation. That does make sense now.