Rainbow colors in some lighting environments

[Demon]

Date: 5/17/2009 7:40:05 PM
Author: strmrdr

Date: 5/17/2009 7:24:52 PM
Author: Demon
Ok, I kind of get what you''re saying about leakage and different lighting, but what is standard gemological lighting, exactly?

broad spectrum fluorescent tubes over the side of the diamond at close range.
Here is why it is deceptive...
Top image is simulated gemological lighting second is simulated real world over a dark background.
light on it looks bright, light off it looks ugly which it is.

Ugly it is!!

 

[Demon]

Date: 5/17/2009 10:10:50 PM
Author: Garry H (Cut Nut)

Date: 5/17/2009 7:22:41 PM
Author: Demon

Date: 5/17/2009 3:45:42 PM
Author: Garry H (Cut Nut)

Date: 5/17/2009 3:07:26 PM
Author: Daisi2112

Date: 5/17/2009 1:28:23 PM
Author: Demon
Something weird I''ve noticed (kind of on topic?) is that even though my eyes don''t always pick up on individual flashes of fire, when I see the diamond reflected in a window or a mirror (same lighting) there seems to be tons of flashes. Is this something about the properties of glass, or can the eyes not keep up with the stones ''naked'' flashes as well, somehow? Some magnification or something? (I even see more flases reflected in the tile of the shower than looking at the diamond directly??)

Me too, I notice the same thing.

it is exactly what i was talking about - the light is so bright - but further away you see the colors - there is something on Octonus.com to describe it - but have to go now

Thanks - it''d be great if you could point me to it when you get a chance (there''s quite a bit on there!)

Here you are demon
http://www.cutstudy.com/cut/english/grading1/

Thank you Garry. : ) I''ll read that just as soon as I can get to it.

 

[WinkHPD]

Date: 5/17/2009 1:28:23 PM
Author: Demon
Something weird I''ve noticed (kind of on topic?) is that even though my eyes don''t always pick up on individual flashes of fire, when I see the diamond reflected in a window or a mirror (same lighting) there seems to be tons of flashes. Is this something about the properties of glass, or can the eyes not keep up with the stones ''naked'' flashes as well, somehow? Some magnification or something? (I even see more flases reflected in the tile of the shower than looking at the diamond directly??)

This has to do with the width of the flash of dispersion when it reaches your eye. When you are close the smaller flashes will be narrower than the pupil of your eye and thus all of the colors will enter the eye and be seen as white light.

When those flashes have traveled to a mirror and back to your eye they will have had the distance necessary to have spread to a width greater than the width of your pupil thus only part of the colors will enter the eye and will be seen as colored light.

Somewhere there is a thread where this is discussed at greater length after I came back from one of my trips to Vegas for further education about diamond cutting at the feet of Peter Yantzer of the AGS Gem Laboratory. Perhaps John Pollard can point us to it, he seems to remember these things better than I do.

Wink

 

[WinkHPD]

Date: 5/17/2009 4:24:06 PM
Author: Serg

Date: 5/17/2009 12:38:15 AM
Author: Wink

Date: 5/16/2009 11:07:28 PM

Author: Garry H (Cut Nut)

Light return can be the enemy of fire - if there is a lot of light return then the fire can be washed out

If you said ''is the enemy of fire'' rather than ''can'' I would have to vociferously dissagree with you Garry. I can not catagorically state that it is incorrect, just that it is not correct all the time. I deal with diamonds that are cut to the highest standards and have AGS 0 light return and wonderful amounts of fire, so I know that it is not always correct.


I think it may be one of the myths of our business, because I hear so many people say it, yet most of the AGS 0 cut diamonds and AGS 1 cut diamonds that have the AGS 0 light return, at least the ones that I have seen, also exhibit great fire.


Wink

Wink, what definition of Light return do you use?
could you publish explanation what LR is and how we can calculate it?

LOL! No. I am not a scientist, I am a diamond retailer who knows a lot, but not enough to do what you ask. When I see a diamond with AGS 0 light return and wonderful amounts of fire I know that I am seeing a diamond that I like. Perhaps Jim Caudill or Peter Yantzer can give you numbers, I can only give you visions...

Wink

 

[Serg]

Date: 5/17/2009 12:38:15 AM
Author: Wink

Date: 5/16/2009 11:07:28 PM

Author: Garry H (Cut Nut)

Light return can be the enemy of fire - if there is a lot of light return then the fire can be washed out

If you said ''is the enemy of fire'' rather than ''can'' I would have to vociferously dissagree with you Garry. I can not catagorically state that it is incorrect, just that it is not correct all the time. I deal with diamonds that are cut to the highest standards and have AGS 0 light return and wonderful amounts of fire, so I know that it is not always correct.


I think it may be one of the myths of our business, because I hear so many people say it, yet most of the AGS 0 cut diamonds and AGS 1 cut diamonds that have the AGS 0 light return, at least the ones that I have seen, also exhibit great fire.


Wink

I think, I just have found way to explain Garry statement with next Mind experience:
Take 2 Diamonds: First diamond with best Light return, Second with Best Fire .
Will its same diamonds?
If its are different diamonds, Second should have less Light return than First.


It works for any Light return and Fire definition
I do not know LR and Fire definitions When its could be same diamonds

 

[Demon]

Date: 5/18/2009 7:16:14 PM
Author: Wink

Date: 5/17/2009 1:28:23 PM
Author: Demon
Something weird I''ve noticed (kind of on topic?) is that even though my eyes don''t always pick up on individual flashes of fire, when I see the diamond reflected in a window or a mirror (same lighting) there seems to be tons of flashes. Is this something about the properties of glass, or can the eyes not keep up with the stones ''naked'' flashes as well, somehow? Some magnification or something? (I even see more flases reflected in the tile of the shower than looking at the diamond directly??)

This has to do with the width of the flash of dispersion when it reaches your eye. When you are close the smaller flashes will be narrower than the pupil of your eye and thus all of the colors will enter the eye and be seen as white light.

When those flashes have traveled to a mirror and back to your eye they will have had the distance necessary to have spread to a width greater than the width of your pupil thus only part of the colors will enter the eye and will be seen as colored light.

Somewhere there is a thread where this is discussed at greater length after I came back from one of my trips to Vegas for further education about diamond cutting at the feet of Peter Yantzer of the AGS Gem Laboratory. Perhaps John Pollard can point us to it, he seems to remember these things better than I do.

Wink

That explanation helps a lot! Thanks.

 

[Garry H (Cut Nut)]

Date: 5/19/2009 12:16:33 PM
Author: Serg

Date: 5/17/2009 12:38:15 AM
Author: Wink

Date: 5/16/2009 11:07:28 PM

Author: Garry H (Cut Nut)

Light return can be the enemy of fire - if there is a lot of light return then the fire can be washed out

If you said ''is the enemy of fire'' rather than ''can'' I would have to vociferously dissagree with you Garry. I can not catagorically state that it is incorrect, just that it is not correct all the time. I deal with diamonds that are cut to the highest standards and have AGS 0 light return and wonderful amounts of fire, so I know that it is not always correct.


I think it may be one of the myths of our business, because I hear so many people say it, yet most of the AGS 0 cut diamonds and AGS 1 cut diamonds that have the AGS 0 light return, at least the ones that I have seen, also exhibit great fire.


Wink

I think, I just have found way to explain Garry statement with next Mind experience:
Take 2 Diamonds: First diamond with best Light return, Second with Best Fire .
Will its same diamonds?
If its are different diamonds, Second should have less Light return than First.


It works for any Light return and Fire definition
I do not know LR and Fire definitions When its could be same diamonds

My mind is hurting.
A good test is what would happen with a diamond with bad LR?
Or a diamond with exceptional LR?

And at what angle should we consider - only face up?
I think the brighter the diamond the less fire you see.
But not the other way around - duller diamonds do not have more fire for you to see.

 

[strmrdr]

Date: 5/20/2009 3:32:16 AM
Author: Garry H (Cut Nut)
My mind is hurting.

A good test is what would happen with a diamond with bad LR?

Or a diamond with exceptional LR?


And at what angle should we consider - only face up?

I think the brighter the diamond the less fire you see.

But not the other way around - duller diamonds do not have more fire for you to see.

They can have....
The problem is the term more fire has multiple meanings....

1: in optimal fire producing light has as much fire as another, but shows fire in more lighting conditions than the diamond it is being compared to.

2: has smaller but numerous fire events.

3: has larger more visible fire events that are more often seen as fire.

Each of those can be called having more fire and are 3 distinct and separate personalities in a diamond and 3 different design considerations.