WHY do people want whiter diamonds?

[Niel]

I had brought my marquise to get sized a while back. The guy there told me they face up whiter because of the n/s facetting.

I found that different than anything I had heard on this site.

 

[yssie]

Hello Tourmalaine, I had a D/E VVS2 Oval once.. it's color was pure white, EXCEPT the bowtie was just toooo annoying for me.. so I can understand the love of a DEF, but I then traded up to a G/H round VS2 that popped more.... so I think color is just one of several things.. the ring that Kim Karsashian has now is to die for.. I would love a stone like that but at the 1.5 2.0 carat (okay 3) size.. it's like ICE! I just love diamonds I guess.

Hi Andelain!

Tekate, when it comes to fancies like pear, marquise & ovals that graphic that Garry posted earlier really comes to play on these regardless of bowties simply because of the nature of how much light leakage exists in these shapes. If a person is the slightest bit color sensitive I generally recommend D-G with H's in some circumstances if it is exceptionally cut. Garry or Karl if you're reading could you post up a DiamCalc image to show this if you can to demonstrate? I'm on my laptop at home.

All the best,
Rhino

Hi Rhino,
Not sure what you want me to show?
For the record, Bow Ties are the nail head effect where your head and body is obscuring the light sources causing the dark zones. They are never caused by leakage.
And the leakage is not simply the cause of more color face up - its the length of the ray trace in various parts of the diamond.
The example of the emerald cut with strong yellow zones that Karl posted a page or two back has good straight in straight our brightness in the center, but yellow near the ends.
If you want to see more color then you can also mess up the symmetry in a round cut.

Hi Garry,

LOL... I know the bow tie is not due to leakage. We had that conversation back in 2000 on another forum.

To me there appears to be a correlation between leakage and color entrapment. It may be directly related to the length of the rays as you state and would make for an interesting study. One thing I do know for sure is that those fancy shapes do retain more color than other shapes with ideal optics. If you can, show us a ray trace of say ... a pear or oval. Thanks Garry.

Regards,
Jonathan

Which is interesting, because... one could potentially assume exactly the opposite - that if the light's leaking out the back, well, you aren't seeing it no matter how long the light paths might have been! What you definitely would see are the tertiary refractions, whatever direction the primary refraction winds up exiting the stone... so that's part of it? The highest-energy portion of the path exits out the bottom and what you wind up seeing are all the lower-energy stronger-coloured (thanks to greater absorption) secondary and tertiary refractions that result from the reflected 16% portions of those outbound refractions that have been bouncing around inside the stone for much longer..?

 

[Garry H (Cut Nut)]

Rhino[/quote]
Hi Rhino,
Not sure what you want me to show?
For the record, Bow Ties are the nail head effect where your head and body is obscuring the light sources causing the dark zones. They are never caused by leakage.
And the leakage is not simply the cause of more color face up - its the length of the ray trace in various parts of the diamond.
The example of the emerald cut with strong yellow zones that Karl posted a page or two back has good straight in straight our brightness in the center, but yellow near the ends.
If you want to see more color then you can also mess up the symmetry in a round cut.[/quote]

Hi Garry,

LOL... I know the bow tie is not due to leakage. We had that conversation back in 2000 on another forum.

To me there appears to be a correlation between leakage and color entrapment. It may be directly related to the length of the rays as you state and would make for an interesting study. One thing I do know for sure is that those fancy shapes do retain more color than other shapes with ideal optics. If you can, show us a ray trace of say ... a pear or oval. Thanks Garry.

Regards,
Jonathan[/quote]
I ran a ray in the direction of observation into the strongest yellow part of this DC oval. You can see there is very little leakage, hover the light that is entering is entering from multiple directions and the average of those ray paths might be 30 times the stone diameter (especially if I lowered the minimal intensity and increased the number of reflections (but the image gets all messed up with so many more rays bouncing around).
If I run the ray through the gray areas they are mostly leakage.
The bright pale yellow areas are straight in, off 2 pavilions and mostly straight out to where there is a light source - the same as would happen if the cut was a really nice round brilliant.
if anyone is interested there is one article here and others on the side bar http://www.octonus.com/oct/projects/fancycolor.phtml

 

[Karl_K]

To me there appears to be a correlation between leakage and color entrapment.
Regards,
Jonathan

Jon,
You are both right but for the same reason.
Remember that the vast majority of the time what we call leakage is not real leakage witch happens when the critical angle is crossed. Instead of what we we are seeing is light drawn from the back of the diamond on the opposite side usually and it is more likely than not bounced around a few times creating long light paths.
That combined with less intensity == darker perceived color.
It is similar to color entrapment but with light from the back side of the diamond, not the top.

 

[Karl_K]

Here is a picture of leakage(what we call leakage) interacting with body color.



Note as pure leakage as diamond gets would look pretty close to the background color.
like this:

 

[Garry H (Cut Nut)]

To me there appears to be a correlation between leakage and color entrapment.
Regards,
Jonathan

Jon,
You are both right but for the same reason.
Remember that the vast majority of the time what we call leakage is not real leakage witch happens when the critical angle is crossed. Instead of what we we are seeing is light drawn from the back of the diamond on the opposite side usually and it is more likely than not bounced around a few times creating long light paths.
That combined with less intensity == darker perceived color.
It is similar to color entrapment but with light from the back side of the diamond, not the top.

Sorry folks, we are getting nerdy here
Yes Karl, as you say a darker perceived color - but not attractive as the color will be grey (in colder colors like blueish stones) or brown in the case of warmer hues.
It can be demonstrated with DC also if need be to solve any debate.

 

[Karl_K]

In this image the yellow arrow points to leakage drawn from the opposite side of the diamond.
The red arrow points to true leakage.

 

[yssie]

In this image the yellow arrow points to leakage drawn from the opposite side of the diamond.
The red arrow points to true leakage.

Karl - wouldn't the areas of "true leakage" *look* exactly like the areas of 'leakage drawn from the opposite side of the diamond' IRL? As in, IRL, is there any distinction - I would think that any potential points of exit for rays incident on the diamond/air bound > crit angle would also be potential points of entry for other rays in that same way?

 

[Karl_K]

In this image the yellow arrow points to leakage drawn from the opposite side of the diamond.
The red arrow points to true leakage.

Karl - wouldn't the areas of "true leakage" *look* exactly like the areas of 'leakage drawn from the opposite side of the diamond' IRL? As in, IRL, is there any practical distinction - I would think that any potential points of exit for rays incident the diamond/air bound > crit angle would also be potential points of entry in exactly the same way?

No, they could have different contrast and depending on what was where they were drawing light from different colors.
This is far more noticeable in step cuts than brilliant cuts because the different angles of the rows of pavilion reflectors have the potential to be drawing light from more locations and it has more prevalent patterns.
On the hand the background under a diamond unless it is in a halo is very varied in brightness and color.
A halo tends to grey/shadow everything out under it so not much light gets under it.

 

[Garry H (Cut Nut)]

Yes Karl.
And Yssie here is a ray entering in a yelowish grey zone circled in red where most of the light is exiting out the pavilion and predominantly in one single ray.
A stone with a lot of this overall color would be unattractive, not a fancy color, or at best Fancy Dark or Brownish Yellow.

 

[Karl_K]

I just had to say this is the most fun that I have had on PS in a while.
Thanks
I love this stuff :}

 

[Garry H (Cut Nut)]

I just had to say this is the most fun that I have had on PS in a while.
Thanks
I love this stuff :}

Is that a Tiffany Teal blue virtual emerald cut facet Karl?

 

[lusting]

I had to come out of lurkdom to say a big thank you to everyone who has posted in this thread! The conversation has been truly fascinating, and it's so wonderful to see our Trade members sharing their knowledge. Loving the technical level to which the discussion has reached, despite it being beyond me at the moment. One day I hope to truly get my head around some of these concepts!

My D-coloured pear has also been following the thread closely

Can I ask what is probably a really silly question though? Given what you've just been discussing about light entering from the back of the diamond, does that mean that settings where the diamond is set high can increase 'perceived leakage'? That would be contrary to what I originally thought when I was more of a layman, ie. that stones set higher as opposed to lower (in a ring setting) will make a stone appear brighter.

 

[Tourmaline]

Here is a fun collage that shows the chameleon that is my L diamond. These photos are totally unedited. Top left was taken in a room with blue walls, top right in a room with pink walls, bottom left - yellow walls, bottom middle - ivory walls, bottom right - outside while snowing.

 

[c-k]

Here is a fun collage that shows the chameleon that is my L diamond. These photos are totally unedited. Top left was taken in a room with blue walls, top right in a room with pink walls, bottom left - yellow walls, bottom middle - ivory walls, bottom right - outside while snowing.



Great job...shows the real world, now would a 'D' show the same way?

 

[msop04]

Kim's ring is a good example of why I don't like high color diamonds. I thought I was suppose to which is I believe why it took me so long to find my ring...

Diamonds have personality to me. Stark white ones have a sort of cold lab coat feel. Not all, but most in my eyes. I don't want mine to feel that buttoned up and fancy. I want my diamonds to have distinct and noticeable moods. I feel like, if my diamonds were a person, I'd hang out with them

I wouldn't want to hang out with Kim k's ring.

This cracked me up! I wouldn't wanna hang with KK's ring either -- it seems kinda "Look at me, look at me!!" -- when in reality, no one really cares.

...just proceed with caution if you ask them what they do for a living.

Indeed. Because they might be met with the answer, "Mind your own business, you nosy cow."

Which would be clearly less offensive.

 

[msop04]

Here is a fun collage that shows the chameleon that is my L diamond. These photos are totally unedited. Top left was taken in a room with blue walls, top right in a room with pink walls, bottom left - yellow walls, bottom middle - ivory walls, bottom right - outside while snowing.

Tourmaline, your stone is TDF!! Such a chameleon!! I love it! I'll take your L anyday -- sign me up!!
Edit: I love the flat prongs too!!

 

[Karl_K]

Can I ask what is probably a really silly question though? Given what you've just been discussing about light entering from the back of the diamond, does that mean that settings where the diamond is set high can increase 'perceived leakage'? That would be contrary to what I originally thought when I was more of a layman, ie. that stones set higher as opposed to lower (in a ring setting) will make a stone appear brighter.

High open settings help leaky diamonds, more light reaches behind to be drawn in from the back.
Low, tight settings make them look worse.

However the difference in contrast with the fingers also makes a difference with different setting heights.
That is another nerdy subject altogether.

 

[Ashleigh]

Can I ask what is probably a really silly question though? Given what you've just been discussing about light entering from the back of the diamond, does that mean that settings where the diamond is set high can increase 'perceived leakage'? That would be contrary to what I originally thought when I was more of a layman, ie. that stones set higher as opposed to lower (in a ring setting) will make a stone appear brighter.

High open settings help leaky diamonds, more light reaches behind to be drawn in from the back.
Low, tight settings make them look worse.

However the difference in contrast with the fingers also makes a difference with different setting heights.
That is another nerdy subject altogether.

Karl, what sort of diamond will benefit from an enclosed setting?

 

[Rhino]

I just had to say this is the most fun that I have had on PS in a while.
Thanks
I love this stuff :}

Totally. I was actually thinking of starting a separate thread on the subject and give you and Garry the opportunity to share this knowledge which does impact what we see in diamonds on a daily basis.

Thank you both greatly.

Kindest regards,
Rhino

 

[Rhino]

I had to come out of lurkdom to say a big thank you to everyone who has posted in this thread! The conversation has been truly fascinating, and it's so wonderful to see our Trade members sharing their knowledge. Loving the technical level to which the discussion has reached, despite it being beyond me at the moment. One day I hope to truly get my head around some of these concepts!

My D-coloured pear has also been following the thread closely

Can I ask what is probably a really silly question though? Given what you've just been discussing about light entering from the back of the diamond, does that mean that settings where the diamond is set high can increase 'perceived leakage'? That would be contrary to what I originally thought when I was more of a layman, ie. that stones set higher as opposed to lower (in a ring setting) will make a stone appear brighter.

I would say no mainly and yes in some circumstances.

Based on the studies of optical scientist Jose Sasian who worked with AGS to refine their ASET technology, the theory states that light entering from the 0-45 degree angular spectrum (green in ASET) is weak ... dull illumination as light bouncing off of walls is not bright nor as intense as light entering from the 45-75 degree angular spectrum (red in ASET). Hence dull in = dull out.

If a leaky diamond is raised higher in settings it may have the ability to draw in whatever reflections exist below the horizon but if you stop and think about it .... unless you are on the dance floor of Saturday Night Fever ( ) floors and illumination below the horizon is generally nil. This would actually be the black in AGS ASET's or white in the type of ASET imagery our lab takes.

The circumstances where it may be positive is if the diamond is cut in such a way as to use leakage as points of positive contrast. This would of course require the diamond to be drawing in most reflections from the 45-75 degree angular spectrum (red in ASET) but strategically placed points of leakage to provide contrast.

Kind regards,
Rhino

 

[Rhino]

Here is a fun collage that shows the chameleon that is my L diamond. These photos are totally unedited. Top left was taken in a room with blue walls, top right in a room with pink walls, bottom left - yellow walls, bottom middle - ivory walls, bottom right - outside while snowing.



Great job...shows the real world, now would a 'D' show the same way?

Yes it would. What you are showing is a function of cut and not color.

 

[Karl_K]

Karl, what sort of diamond will benefit from an enclosed setting?

A well cut diamond overall light return should be very min. affected by an inclosed setting and just from the parts covered face up. Tilt can show more changes but nothing earth shattering.
They are bought for the overall look of the ring: halo to make it look bigger etc.

 

[Tourmaline]

Yes it would. What you are showing is a function of cut and not color.

Please note that I posted the photo, but I didn't ask the question about a D diamond. That was someone else, in response to my photo. Interesting, nonetheless! I am guessing that an ideal cut stone would stay more true to its color and would be less affected by changes in lighting, right? (I love the chameleon thing, by the way.)

 

[Karl_K]

Yes it would. What you are showing is a function of cut and not color.

Please note that I posted the photo, but I didn't ask the question about a D diamond. That was someone else, in response to my photo. Interesting, nonetheless! I am guessing that an ideal cut stone would stay more true to its color and would be less affected by changes in lighting, right? (I love the chameleon thing, by the way.)

no,
The top six things affecting the look of any diamond are:
lighting
lighting
lighting
lighting
lighting
cut

 

[Karl_K]

Based on the studies of optical scientist Jose Sasian who worked with AGS to refine their ASET technology, the theory states that light entering from the 0-45 degree angular spectrum (green in ASET) is weak ... dull illumination as light bouncing off of walls is not bright nor as intense as light entering from the 45-75 degree angular spectrum (red in ASET). Hence dull in = dull out.

Rhino

AGS far underestimates the effect of low angle lighting.
Many people spend much of their day or should I say evening where low angle lighting is the brightest lighting.
With the laws mandating cfl it is also very flat and soft light in many cases.
Perfect lighting for omc/oec or other cuts that take advantage of it(*cough* Octavia).
The omc and oec were designed for low level soft lighting that was prevalent in their day.

 

[Texas Leaguer]

Based on the studies of optical scientist Jose Sasian who worked with AGS to refine their ASET technology, the theory states that light entering from the 0-45 degree angular spectrum (green in ASET) is weak ... dull illumination as light bouncing off of walls is not bright nor as intense as light entering from the 45-75 degree angular spectrum (red in ASET). Hence dull in = dull out.

Rhino

AGS far underestimates the effect of low angle lighting.
Many people spend much of their day or should I say evening where low angle lighting is the brightest lighting.

One would think Tourmaline's diamond is drawing alot of low angle light in order to be reflecting the wall colors so dramatically. (Unless the ceiling is also painted the same color or photo is shot with hand perpendicular to the ceiling).
Very interesting collage.

 

[Rhino]

Yes it would. What you are showing is a function of cut and not color.

Please note that I posted the photo, but I didn't ask the question about a D diamond. That was someone else, in response to my photo. Interesting, nonetheless! I am guessing that an ideal cut stone would stay more true to its color and would be less affected by changes in lighting, right? (I love the chameleon thing, by the way.)

woops.

 

[Rhino]

Based on the studies of optical scientist Jose Sasian who worked with AGS to refine their ASET technology, the theory states that light entering from the 0-45 degree angular spectrum (green in ASET) is weak ... dull illumination as light bouncing off of walls is not bright nor as intense as light entering from the 45-75 degree angular spectrum (red in ASET). Hence dull in = dull out.

Rhino

AGS far underestimates the effect of low angle lighting.
Many people spend much of their day or should I say evening where low angle lighting is the brightest lighting.
With the laws mandating cfl it is also very flat and soft light in many cases.
Perfect lighting for omc/oec or other cuts that take advantage of it(*cough* Octavia).
The omc and oec were designed for low level soft lighting that was prevalent in their day.

 

[Niel]

So I just had an convo that was so relevant to this thread.

I am talking to a friend of mine who is shopping for an e ring an considering a FLY oval.

We were talking if they were wierd. Anywho a coworker says "anyone who knows anything about diamonds knows those are junk diamonds"