ASETs and fancy cuts

[Rockdiamond]

Karl- we agree. Light and how it's being used is central to the discussion.
Garry- I do not believe that a light ring would produce sufficient light to produce a photo like that- anything is possible but the picture seems to have quite bright lighting which suggests far more light than a simple light ring.
Does whatever lighting that was used have any relation to a potential real life view?
Of course it has to- the camera saw it so unless the photo was manipulated at least one of a persons eyes might see the diamond with that hole if viewed n similar lighting.
Just an example- if it was a light ring wouldn't a persons head achieve the same effect? Obscuring the center of the brightest light hitting the diamond.
This is not to insult the diamond- rather assessing where the light was coming from and the visual effect produced.

 

[Rockdiamond]

The photo does seem to have been taken in a well-thought-out lighting set up. Just a bad one for that stone? What would prevent light from returning from the center?

I did not take this photo is was done 7 years ago and we agree it is not the most flattering for the stone.
To make it easier to visualize I will show you the scan generated ASET with the photo.

It isn't just the centre being dark, it isn't the camera lense being reflected(that is at much higher angles) it is the absence of light from lower angles. All all the light is coming from behind the camera or at the higher angles and none from reflections off other surfaces or from lower angles.

I have outlined the dark areas of the photo in green and you can see the ASET is predominantly green in these regions. As I mentioned before the middle region near the culet gathers like from 44 - 47 degrees right at the interface of the Red/Green boundary so a very slight tilt or movement of the stone can turn that region from green to red or vice versa in a photographed ASET. In this case the scan generated ASET is a better match to the photograph.

So your assertion is that the first ASET is inaccurate?
I agree the scan generated ASET far more closely mirrors the picture

 

[Karl_K]

So your assertion is that the first ASET is inaccurate?
I agree the scan generated ASET far more closely mirrors the picture

When the angles are right on the edge the girdle plain in relation to the scope is critical.
That explains the difference.
Take your ASET scope and grab a few diamonds and move them back and forth in and out of the scope just tiny amounts and look at how it changes
With some it will not make a change except with large movement but a few the slightest movement in and out of the scope will dramatically change parts of the image.
The placement is much more critical with fancies than rounds.
Some of them you can look at them in ASET a 100 times and never see the same image twice.
It is a large weakness of any scope based system.

 

[Garry H (Cut Nut)]

Karl- we agree. Light and how it's being used is central to the discussion.
Garry- I do not believe that a light ring would produce sufficient light to produce a photo like that- anything is possible but the picture seems to have quite bright lighting which suggests far more light than a simple light ring.
Does whatever lighting that was used have any relation to a potential real life view?
Of course it has to- the camera saw it so unless the photo was manipulated at least one of a persons eyes might see the diamond with that hole if viewed n similar lighting.
Just an example- if it was a light ring wouldn't a persons head achieve the same effect? Obscuring the center of the brightest light hitting the diamond.
This is not to insult the diamond- rather assessing where the light was coming from and the visual effect produced.

David, Melesinde stated the dark central zone is a result of there being no light at all in the 44 to 47 degree zone.
in this rough image, the ring light might be where the two yellow circles are.
The dark zone could be in black, e.g. the housing behind part of the lamp, and the region below that angle (grey) may be from ambient room lighting.
There is a common misconception that more light makes a diamond photographed look brighter.
Not always true.

 

[Garry H (Cut Nut)]

The photo does seem to have been taken in a well-thought-out lighting set up. Just a bad one for that stone? What would prevent light from returning from the center?

I did not take this photo is was done 7 years ago and we agree it is not the most flattering for the stone.
To make it easier to visualize I will show you the scan generated ASET with the photo.

It isn't just the centre being dark, it isn't the camera lense being reflected(that is at much higher angles) it is the absence of light from lower angles. All all the light is coming from behind the camera or at the higher angles and none from reflections off other surfaces or from lower angles.

I have outlined the dark areas of the photo in green and you can see the ASET is predominantly green in these regions. As I mentioned before the middle region near the culet gathers like from 44 - 47 degrees right at the interface of the Red/Green boundary so a very slight tilt or movement of the stone can turn that region from green to red or vice versa in a photographed ASET. In this case the scan generated ASET is a better match to the photograph.

In the ASET Melesinde posted (below) that was made with DiamCalc we can see the center is now green. This means light is coming from below 45 degrees. In the earlier hand held ASET we see this area is both red and green - therefore we can guess that the central region is drawing light from very close to the 45 degree cut off between red and green in ASET.
With a Tolkowsky 40.75 degree pavilion angled Round a simialr affect occours - and often we see a 40.7 pavilion showing green where as a 40.8 pavilion can show red (depending on the accuracy of the 45 degree positioning of that boundary).
So if that zone that Melesnde suggests - 44-47 was dark, then the culet region will indeed be dark.
DiamCalc enables you to create different lighting models - so here I have done a white dome with a small dark zone at those angles, and walla! The central region is dark.

 

[MelisendeDiamonds]

Milisende

My company name is Melisende Diamonds not Milisende thanks.

I have posted here relatively infrequently over the years and always for the purpose of ensuring that information provided about radiant cuts was informative and accurate.

I will take this opportunity during the beginning of our debate to thank you for participating here. I'd be interested and would be appreciative if you and Rockdiamond could provide photographs, images and a scan of an ORC with around the same 1.38 LW ratio as the stone in that other thread. I'd be interesting in a more in depth of analysis of how well cut rectangular stone can handle the head shadow problem without losing brilliance.

While you are certainly entitled to disagree with anything that I write, and to say so, at no time did I say (or imply) that a bowtie was the result of leakage, though I seriously doubt that those who don't like bowties care a whit about what causes it.

Yes I agree with you there and I don't see where you ever used the word bowtie in that thread. But I would add head shadow can be completely removed if one moves their head further away, leakage is going to manifest itself no matter where the viewer is situated.
In that thread I question how persistant those dark regions were upon tilt and that unfortunately was not the focus of the thread.

I was describing, in generic terms, how in my opinion a well cut radiant reflects light, both straight on and with some tilt

I understood your point. Generally when our suppliers cut diamonds, tilt window isn't really a concern, they don't cut pavilion angles anywhere close to the diamond/air critical angle of 24.5. But I'd imagine in your Radiant cut design where you cut to more shallow pavilion angles that could be an issue you want to avoid.

Since his concern was about assymetry of life, I also explained why it was possible to have assymetrical life in a diamond having VG symmetry by GIA.

Well we agree again, physical meet point symmetry as graded by GIA is very different from optical symmetry(what you call life) and that is a good point. However I rarely see much optical symmetry in any higher LW ratio diamond even a strict twofold optical symmetry axis is rare.

I stand by every word in my post, and find your assertion that I misled a consumer with incorrect information to be extremely unfortunate since my only goal in posting is to help consumers sort through the mountain of information and misinformation that they confront during the shopping process.

Again the point of my post above was about interpretation of the photograph, your general information on Radiant cuts is not in dispute. You did however mention a tilt window in that thread which I think we both agree did not apply to the dark areas seen in the photographs.

I also disagree that having an ASET image available makes it less likely that consumers will receive well intentioned bad advice, since just like photos, ASETs can and often are misinterpreted, or can be interpreted in a manner which introduces subjective bias.

Well we will have to agree to disagree on that point, ASET is telling me about the potential brilliance and is an objective tool allowing me to compare diamonds on the basis of brilliance.

I do agree with you in that brilliance is not the only criteria for the subjective overall beauty assessment and that if the ASET is used as the only indicator of beauty that would indicate a bias and one that is often inappropriate for most consumers in their selection of a cut cornered square.

 

[MelisendeDiamonds]

So if that zone that Melesnde suggests - 44-47 was dark, then the culet region will indeed be dark.
DiamCalc enables you to create different lighting models - so here I have done a white dome with a small dark zone at those angles, and walla! The central region is dark.

Garry I think its closer to this, where there is no significant light source below 47.5 degrees and camera shadow above 78 degrees.
Not the most flattering lighting for almost any diamond.

 

[MelisendeDiamonds]

Not the most flattering lighting for almost any diamond.

Look what the ORC Radiant would look like under this lighting.

 

[Karl_K]

So if that zone that Melesnde suggests - 44-47 was dark, then the culet region will indeed be dark.
DiamCalc enables you to create different lighting models - so here I have done a white dome with a small dark zone at those angles, and walla! The central region is dark.

Garry I think its closer to this, where there is no significant light source below 47.5 degrees and camera shadow above 78 degrees.
Not the most flattering lighting for almost any diamond.

I see it fairly often with princess cuts which that stone has a princess pavilion.
It stems from photo setups designed for rounds where they don't have to worry about much of anything but very high angle lighting with lots of obstruction to pop the arrows.
Not real world, but makes rounds look good.
On the other hand it can make many high performance fancies look less than they really are in person.
Which brings me back to my 2 other posts in this thread: they one showing how one fancy draws lighting from a wider angle range than tolk. and the lighting lighting lighting lighting lighting post.

 

[smitcompton]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

 

[Karl_K]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

It is a case by case basis, there is no one answer that covers all possibilities over 3 different cuts with many variations.
For example by allowing small amounts of "leakage" in my design I get around 10% more brightness overall.

 

[Rockdiamond]

Great points Karl- not only are they 3 different cuts, within each category of cut, there's important variations.
Just as an example - longer rectangular shaped diamonds present unique challenges.
Melisendre- we have picked a few examples to use- they have been photographed- however I realize now that Ella mentioned using stones that had been previously been sold so as to avoid breaking the rules.
I will send a message to Ella to see what is possible.


Karl- another point regarding lighting, photography and ASET.
is it possible that different ASET photography methods need to be used for different cuts. For example the stone with the dark area seems better represented by scan generated ASET.

 

[Karl_K]

Karl- another point regarding lighting, photography and ASET.
is it possible that different ASET photography methods need to be used for different cuts. For example the stone with the dark area seems better represented by scan generated ASET.

Yes and no, the optimal way to do it for the most accurate results are the same.
However with a reasonably well cut RB you can more or less throw it under there and get useable results where with fancies it is much more picky about setting it up right.
Scan generated ASETs have their own issues, if you go back in this thread and view the wire frame views posted you will see some results on one that are very highly improbable to be accurate.(split facets that would result in a poor symmetry grade)
This is worse with fancies because they often have facets that are close in angle to one another and facets running in directions different than the scanner is calibrated for.
The greater the angle between 2 facets the better and more accurate the scanner can separate them.
Which is why I mentioned earlier to you to check the virtual ASETs against real ones.

 

[Garry H (Cut Nut)]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

Perhaps you mean the zone around this central region that has considerable leakage?
This is not desirable in a colourless diamond smitcompton. in a fancy pale diamond it can be good if more of the stone is green, with little or mo red or blue.

 

[Garry H (Cut Nut)]

Milisende

While you are certainly entitled to disagree with anything that I write, and to say so, at no time did I say (or imply) that a bowtie was the result of leakage, though I seriously doubt that those who don't like bowties care a whit about what causes it.

Yes I agree with you there and I don't see where you ever used the word bowtie in that thread. But I would add head shadow can be completely removed if one moves their head further away, leakage is going to manifest itself no matter where the viewer is situated.
In that thread I question how persistant those dark regions were upon tilt and that unfortunately was not the focus of the thread.

Leakage effects are interesting from different distances. I think the closer you get to a diamond, sometimes leakage is canceled out when one eye sees a bright zone and the other sees a leakage in exactly the same virtual facet - we see a brightness in our mind / brain. The stereo vision effect is stronger closer up because each eye has a very different viewing angle. (again - rock the stone a little when using a hand held ASET, or tilt left and right in DiamCalc).

BTW can anyone remember when (or if) GIA education stopped calling marquise bow ties a result of leakage? Same for nail head deep rounds?

 

[Garry H (Cut Nut)]

So if that zone that Melesnde suggests - 44-47 was dark, then the culet region will indeed be dark.
DiamCalc enables you to create different lighting models - so here I have done a white dome with a small dark zone at those angles, and walla! The central region is dark.

Garry I think its closer to this, where there is no significant light source below 47.5 degrees and camera shadow above 78 degrees.
Not the most flattering lighting for almost any diamond.

Excellent Melisende (apologies if I typo'ed your name too in other posts).
would you like to show a round tolkowsky in that lighting model?

 

[jazzandchocolate]

This thread is EXTREMELY informative to me, especially because I adore fancy cut diamonds over any shape, so thank you!

Question: With all of the marquise threads popping up lately (yay...Lol!) what do you all recommend when looking at an ASET of a fancy cut? Assuming that the buyer has seen the original diamonds in person, but they just can't decide...or if seeing them in person is not an option, what is it that the buyer should look for when viewing an ASET of a fancy cut? (I know about the bowties, but feel free to mention it again for those that may not be aware of them.) Also, if ASETs really don't add any valuable info to fancies, feel free to share that as well.

 

[Garry H (Cut Nut)]

This thread is EXTREMELY informative to me, especially because I adore fancy cut diamonds over any shape, so thank you!

Question: With all of the marquise threads popping up lately (yay...Lol!) what do you all recommend when looking at an ASET of a fancy cut? Assuming that the buyer has seen the original diamonds in person, but they just can't decide...or if seeing them in person is not an option, what is it that the buyer should look for when viewing an ASET of a fancy cut? (I know about the bowties, but feel free to mention it again for those that may not be aware of them.) Also, if ASETs really don't add any valuable info to fancies, feel free to share that as well.

Its off topic, but here you go JC. Most traditional marquise have a pavilion main facet running across the stone. The second type in the lower image usually have less bowtie problems. But in general, no bow tie can mean less light return near the tips and other places.
To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

 

[jazzandchocolate]

To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

Sorry, I'm not following...

 

[Garry H (Cut Nut)]

To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

Sorry, I'm not following...

The bow tie is you and your head and body being seen through the diamond.
Another way to check it is to shine a bright torch on your face, or put a red bag over your head with two peep holes. The dark bowtie will go sjkin colored or red bag colored

 

[MelisendeDiamonds]

To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

Sorry, I'm not following...

A bowtie reflects objects or light at high angles where your head is and appears dark because of the shadow cast by your head. If however your head was covered in white paper and didn't cast a shadow on your diamond then the bowtie would not appear dark anymore it would be reflecting white. That is a test and how Garry has proven to many that a bowtie is dark due to head shadow obstruction not due to leakage which is what GIA has incorrectly taught.

It is however not really answering your question. In a marquise ASET you are looking for minimal bowtie, so not a large strip of blue across the middle of the stone, you are also looking for a nice distribution of red and green throughout the stone and on the tips and no large patches of white concentrated in any one area in an ASET.

 

[MelisendeDiamonds]

Excellent Melisende (apologies if I typo'ed your name too in other posts).
would you like to show a round tolkowsky in that lighting model?

 

[jazzandchocolate]

To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

Sorry, I'm not following...

A bowtie reflects objects or light at high angles where your head is and appears dark because of the shadow cast by your head. If however your head was covered in white paper and didn't cast a shadow on your diamond then the bowtie would not appear dark anymore it would be reflecting white. That is a test and how Garry has proven to many that a bowtie is dark due to head shadow obstruction not due to leakage which is what GIA has incorrectly taught.

It is however not really answering your question. In a marquise ASET you are looking for minimal bowtie, so not a large strip of blue across the middle of the stone, you are also looking for a nice distribution of red and green throughout the stone and on the tips and no large patches of white concentrated in any one area in an ASET.

Got it! I wasn't really anticipating a hair color change, and then I thought it was an inside joke between diamond enthusiasts/experts that I wasn't privy to! Thanks for the explanation...and thank you as well Garry!

This raises a new question, because I've always thought that bowties were created from either poor cutting or the longer proportions that most fancies (ovals, pears, marquises) have to abide by....the question is if the bowties are not due to light leakage, then why do some fancies not have bowties, some prominent, and some minimal?

 

[Garry H (Cut Nut)]

To make a bow tie disappear dye your hair blonde, or poke a peep hole in a sheet of white copy paper and the observer obstruction that causes it will disappear.

Sorry, I'm not following...

A bowtie reflects objects or light at high angles where your head is and appears dark because of the shadow cast by your head. If however your head was covered in white paper and didn't cast a shadow on your diamond then the bowtie would not appear dark anymore it would be reflecting white. That is a test and how Garry has proven to many that a bowtie is dark due to head shadow obstruction not due to leakage which is what GIA has incorrectly taught.

It is however not really answering your question. In a marquise ASET you are looking for minimal bowtie, so not a large strip of blue across the middle of the stone, you are also looking for a nice distribution of red and green throughout the stone and on the tips and no large patches of white concentrated in any one area in an ASET.

Got it! I wasn't really anticipating a hair color change, and then I thought it was an inside joke between diamond enthusiasts/experts that I wasn't privy to! Thanks for the explanation...and thank you as well Garry!

This raises a new question, because I've always thought that bowties were created from either poor cutting or the longer proportions that most fancies (ovals, pears, marquises) have to abide by....the question is if the bowties are not due to light leakage, then why do some fancies not have bowties, some prominent, and some minimal?

The dark 8 pointed star you see in a round diamond is exactly the same as the bow tie, but they are nicely dispersed around the stone and shift from dark to very bright as you rock the diamond. That is contrast. I hope we might soon be able to link to or publish some a journal article about some of these features of what we see and why diamonds are so special. Same thing happens with a marquise (oval and pear) bowtie, but because they are localised they are considered unatractive or 'dark zones'.
Leakage is the other cause of dark zones - and that is totally diffferent - as Karl mentions some leakage can also help provide some contrast, so just as with obstruction (blue in ASET) the dark is important to provide the sparkle.
it can not be made simple - and it largely depends on complex stuff going on in our heads!

 

[jazzandchocolate]

Wow...so much more to think about now! So, is it safe to say that there is no wrong or right answer about bowties, as long as it doesn't impact the beauty of the stone? I've seen recuts that have gotten rid of most of the bowtie. Maybe adding extra facets allowed the facets to cancel out each other's reflection, therefore giving the appearance of no bowtie? Or maybe recutting created better contrast?

 

[Garry H (Cut Nut)]

Wow...so much more to think about now! So, is it safe to say that there is no wrong or right answer about bowties, as long as it doesn't impact the beauty of the stone? I've seen recuts that have gotten rid of most of the bowtie. Maybe adding extra facets allowed the facets to cancel out each other's reflection, therefore giving the appearance of no bowtie? Or maybe recutting created better contrast?

I imagine the vast majority of people do not like Bowties. But maybe some people do??
Changing the facet structure can remove the bow tie, yes. As with the two different types in the example I posted.

 

[diagem]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

Perhaps you mean the zone around this central region that has considerable leakage?
This is not desirable in a colourless diamond smitcompton. in a fancy pale diamond it can be good if more of the stone is green, with little or mo red or blue.

Garry, the actual Diamond in the picture you posted is on a black background.
We notice that "ring" area is not actually all leakage, I even think most of that area is lit up by light entering just below 45 degrees, an area AGSL doesnt take into consideration when grading for LP (thats without taking tilt into consideration on this specific example you posted).
In my opinion, this area could be designed in such way it becomes a positive visual thus minimizing the deduction for leakage.

You're take?

 

[Garry H (Cut Nut)]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

Perhaps you mean the zone around this central region that has considerable leakage?
This is not desirable in a colourless diamond smitcompton. in a fancy pale diamond it can be good if more of the stone is green, with little or mo red or blue.

Garry, the actual Diamond in the picture you posted is on a black background.
We notice that "ring" area is not actually all leakage, I even think most of that area is lit up by light entering just below 45 degrees, an area AGSL doesnt take into consideration when grading for LP (thats without taking tilt into consideration on this specific example you posted).
In my opinion, this area could be designed in such way it becomes a positive visual thus minimizing the deduction for leakage.

You're take?

Its pretty much a black hole Yoram

 

[diagem]

Hi All,

I was looking forward to this thread as I was looking at radiant, asscher and cushion cut diamonds for a possible purchase. I am not one of the knowledgeable consumers who frequent this board. I was hoping to see asets for those makes. So here is my question.

I have noticed in these cuts, the center of the aset is red, but is ringed by the white color, to form a square(ish) surround. The the color moves to red, green, blue and possibly more white. Is this ring around the red center, light leakage, and does it denote something a diamond buyer would best avoid?

David, you usually divert the conversation to what suits you. . I want to use the aset as a selection tool, along with seeing the diamond, after checking the aset, but consumers need to read them properly, so please let the others continue to show us asets. (or start.)

Thanks,

Annette

Perhaps you mean the zone around this central region that has considerable leakage?
This is not desirable in a colourless diamond smitcompton. in a fancy pale diamond it can be good if more of the stone is green, with little or mo red or blue.

Garry, the actual Diamond in the picture you posted is on a black background.
We notice that "ring" area is not actually all leakage, I even think most of that area is lit up by light entering just below 45 degrees, an area AGSL doesnt take into consideration when grading for LP (thats without taking tilt into consideration on this specific example you posted).
In my opinion, this area could be designed in such way it becomes a positive visual thus minimizing the deduction for leakage.

You're take?

Its pretty much a black hole Yoram

What would you call this hole Garry?

 

[MelisendeDiamonds]

Garry, the actual Diamond in the picture you posted is on a black background.
We notice that "ring" area is not actually all leakage, I even think most of that area is lit up by light entering just below 45 degrees, an area AGSL doesnt take into consideration when grading for LP (thats without taking tilt into consideration on this specific example you posted).

Hi Diagem,

I am not Garry but I can hopefully help this question which I believe is about AGS-PGS cut grading. (Not just a plain ASET 30 image which we are discussing here).

I believe the border areas Red/Green (43 - 44 - 44.9) are treated differently by AGSL cut grading for LP, its a scaled penalty and closer to 45 the lesser the deduction. But if those Green regions are mostly white with a hint of Green than its mostly leakage like in Garry's example and should be more heavily penalized.

Over the years AGSL has started to allow diamonds with larger culets to still get AGSL 0 (like your example), I beleive they encourage new designs and set tolerances on a case by case basis which allow things like more blue in a princess cut, 20% green in a fancy etc.