Steep Deep diamonds have lower face up color

[Garry H (Cut Nut)]

It just occured to me, that the diamonds closer to the upper boundary of GIA''s have lower color in the table leakage zone because of multiple ray paths bouncing around inside the stone in that area.

Another good reason to change a bad system.

 

[strmrdr]

depends on the lighting, but yes the light paths are longer so it will pick up more color.
But in lighting where body color is actually an issue will it have an effect?
Because if you are seeing diamond color the diamond isn''t returning a lot of light.
The majority of the time with a well cut RB for a fairly large range in body color it is irrelevant to what one will see.

 

[strmrdr]

Same body color for both.
DC tolk and 35.50/41.5 rest the same as DC tolk.
Lighting ISO no head.

 

[strmrdr]

Same combos in simulated Marty type lighting.
No color differences that can be attributed to absorption that I see.

 

[Garry H (Cut Nut)]

I am not sure what those images show Storm.
But here you can see a slight difference.
Both diamonds are the same weight.
One is a VG sym real stone.

When you do this the face up view should probably be what each eye will see - so I tilted 5 degrees.
When we are looking for color, each eye will see some - just as when we look for fire, 2 eyes see more than one.

 

[strmrdr]

Garry I am agreeing with you that it makes a slight difference.
That the better cut diamond shows body color less often because it is being masked by light return is a much bigger difference than slight light path differences in my opinion.
When we talk a radiant vs a RB then there is enough difference in the light path and brightness for there to be a more real world difference.

 

[John P]

Hey Garry, I've been beating that drum since 2006. Nice that you're dancing to the beat now.

Date: 6/18/2009 9:19:26 AM
Author: strmrdr

When we talk a radiant vs a RB then there is enough difference in the light path and brightness for there to be a more real world difference.

True that.

Diamond cutters have known these tricks for a loooong time. It's the reason you'll find angle combos on colored stones the HCA would hate; since the idea in those cases is to keep the light path inside the diamond long enough to illuminate/exaggerate body color.

 

[Kelli]

I know this isn''t very technical, so delete if you like. But here are before and after pics of my stone, taken in the same room, facing the same direction, at the same time of day. Pic #1 is before the recut, GIA excellent with 35.5 CA and 41.2 PA.

 

[Kelli]

Here is pic #2, after the recut. CA is 34.5 and PA is 40.7.

 

[Kelli]

It did actually go up a color grade too, but it was sent to the AGS instead of the GIA after the recut, so that may be why. It really does look a lot brighter and whiter now though. Even more than you can see in the pics, because they were lit up from behind.

 

[Garry H (Cut Nut)]

Date: 6/18/2009 12:27:43 PM
Author: Kelli
Here is pic #2, after the recut. CA is 34.5 and PA is 40.7.

Its a great example Kelli - especially in the zone inside the table excluding the star pattern.