ASETs and fancy cuts

[Texas Leaguer]

Great post John.
What this means is that consumers posting ASET images for interpretation are getting opinions based on interpretations. There's no agreed upon "best" - but new readers think they're getting some sort of quantitative results or info.
That's an issue IMO

If we are going to compare ASET images than than the majority (or all) of the participants should at least except what is a more intense light source and the premise upon which ASET is built.

That will TOTALLY defeat the purpose of the discussion.
The point is to remove the subjective aspect and deal with objective observation.
It makes ZERO difference which light is more intense for the purposes of figuring out how to use ASET on stones cut for scintillation and spread.

We can all agree how the ASET works- and how it represents the light coming into and out of the diamond- yet we need to remove the subjective aspect as to which type of light is better.

David, I didn't see where anyone said anything about better light. It was a simple statement about the basic premise of the ASET tool and what the color codes represent. Please don't manufacture things to argue against, or put words in other peoples mouths. If you do then another potentially fruitful discussion will spiral down in an endless loop.

 

[Rockdiamond]

Thanks Bryan- I will make every attempt not to read into things.
Here's why I feel charts like the one posted go against a balanced discussion- it seems like MORE intense somehow sounds "better" or more desirable than LESS intense. This can influence how we look at results versus real life.

Basically, if we all agreed on this, there'd be no discussion.
By voicing different opinions, there's got to be a bit of back and forth, which may indeed involve people holding contrary positions.

Hopefully everyone will leave their weapons at the door

 

[John P]

I tend to abandon threads where people are using similar vocabulary but seem to insist on playing different games: If one person applies NFL rules and another applies CFL rules the fundamental length of the field is a contradiction. So, while discussion using football terms and ideas is happening, no consensus can happen because the playing fields are ultimately different. In such threads heads still pound bricks over fundamentals many pages later.

I would like to feel no one is dissembling. In that spirit:

Here's why I feel charts like the one posted go against a balanced discussion- it seems like MORE intense somehow sounds "better" or more desirable than LESS intense.

More is more.

Alcohol proof is a measure of how much alcohol (ethanol) is contained in an alcoholic beverage. In the United States, alcohol content is measured in terms of the percentage of alcohol by volume:

100% ABV (200 proof) is the MOST intoxicating.
80% ABV (160 proof) is LESS intoxicating.

ASET shows where a diamond is returning or not returning light to a viewer's eyes. In this standardized and repeatable environment, given lighting-from-overhead, with 30-40 degrees from high sources blocked by head/body:

RED (drawn from 45-75 degrees) is the most intense light seen by the viewer's eyes.
GREEN (drawn from 0-25 degrees) is less intense.

More is more: 200 proof is the most intoxicating ABV. And RED is the most intense light return seen in ASET.

What's "better" is a matter of context and taste. But as a fundamental baseline of discussion - whether moonshine or diamond-shine - I submit that more simply means more in the repeatable structured environment being discussed in this thread.

 

[Rockdiamond]

I think the vocabulary is central to the issue John.
Charts calling red "MORE" and Green "LESS" are designed to highlight advantages of one cutting style while putting the other in a lesser category.
In your example, you're proving my point.
Checking proof on alcohol is a chemical test, and the correlation to real life is far more precise.
Any 200 proof drink is stronger than a 100 proof drink.
Light return measurement is affected by so many factors making correlation to real life far more complex.
For example, how much light a diamond returns is definitely influenced by their position in relation to the light.
Therefore, for the purposes of a balanced discussion we could more accurately describe red in the aset as an indication of more intense light coming out of the table when the diamond is perpendicular to the light source- which is how ASET measures it.
But not necessarily how we view the diamond consistently in real life.
So even though the ASET shows MORE intense reflections, not all people perceive it that way.



Maybe the issue can be resolved this way: we can agree that a well cut round brilliant, or a fancy shaped stone with more red in aset ( sometimes) produces more intense white light return as compared to the type of diamond that shows a lot of green in the aset.
This in no way makes the round a "more intense" diamond, a better diamond, a prettier diamond, or even a diamond with a better cut.

 

[Texas Leaguer]

I tend to abandon threads where people are using similar vocabulary but seem to insist on playing different games: If one person applies NFL rules and another applies CFL rules the fundamental length of the field is a contradiction. So, while discussion using football terms and ideas is happening, no consensus can happen because the playing fields are ultimately different. In such threads heads still pound bricks over fundamentals many pages later.

I would like to feel no one is dissembling. In that spirit:

Here's why I feel charts like the one posted go against a balanced discussion- it seems like MORE intense somehow sounds "better" or more desirable than LESS intense.

More is more.

Alcohol proof is a measure of how much alcohol (ethanol) is contained in an alcoholic beverage. In the United States, alcohol content is measured in terms of the percentage of alcohol by volume:

100% ABV (200 proof) is the MOST intoxicating.
80% ABV (160 proof) is LESS intoxicating.

ASET shows where a diamond is returning or not returning light to a viewer's eyes. In this standardized and repeatable environment, given lighting-from-overhead, with 30-40 degrees from high sources blocked by head/body:

RED (drawn from 45-75 degrees) is the most intense light seen by the viewer's eyes.
GREEN (drawn from 0-25 degrees) is less intense.

More is more: 200 proof is the most intoxicating ABV. And RED is the most intense light return seen in ASET.

What's "better" is a matter of context and taste. But as a fundamental baseline of discussion - whether moonshine or diamond-shine - I submit that more simply means more in the repeatable structured environment being discussed in this thread.

JP,
methinks it must be 5 o'clock where you are! How else would you be inspired to such a brilliant analogy. Red and green are both good, as are moonshine and diamond-shine! Just different.

One other thing that I will point out is that the operative assumption is that our world is generally lit from above. In lighting environments where the brightest light source is further down on the horizon (such as a room lit with sconces and no overhead) the brightest light would actually be represented by green.

So, knowing something about light return in terms of the angular spectrum can help you to predict a diamonds appearance in different lighting scenarios.

 

[John P]

Light return measurement is affected by so many factors making correlation to real life far more complex.
For example, how much light a diamond returns is definitely influenced by their position in relation to the light. Therefore, for the purposes of a balanced discussion we could more accurately describe red in the aset as an indication of more intense light coming out of the table when the diamond is perpendicular to the light source- which is how ASET measures it.

David: As your comment above (in red) was the very point of my post (read again the bolded below) it seems you are making my point.

ASET shows where a diamond is returning or not returning light to a viewer's eyes. In this standardized and repeatable environment, given lighting-from-overhead, with 30-40 degrees from high sources blocked by head/body:
...
More is more: 200 proof is the most intoxicating ABV. And RED is the most intense light return seen in ASET.
...
What's "better" is a matter of context and taste. But as a fundamental baseline of discussion - whether moonshine or diamond-shine - I submit that more simply means more in the repeatable structured environment being discussed in this thread.

 

[John P]

JP,
methinks it must be 5 o'clock where you are! How else would you be inspired to such a brilliant analogy. Red and green are both good, as are moonshine and diamond-shine! Just different.

A musician might call this time "Prelude to 5." - Thanks for the comment

While we're there, it strikes me that mixing red & green might put one in a Christmas spirit...while mixing moonshine and diamond-shine could cause one to buy presents.

 

[teobdl]

JP,
methinks it must be 5 o'clock where you are! How else would you be inspired to such a brilliant analogy. Red and green are both good, as are moonshine and diamond-shine! Just different.

One other thing that I will point out is that the operative assumption is that our world is generally lit from above. In lighting environments where the brightest light source is further down on the horizon (such as a room lit with sconces and no overhead) the brightest light would actually be represented by green.

So, knowing something about light return in terms of the angular spectrum can help you to predict a diamonds appearance in different lighting scenarios.

I think the bolded portion is critical: "more intense" and "less intense" are contextual to the lighting environment, which is what we are trying to control for by using ASET's in the first place.

What is the problem with just saying what red and green represent? Would "high-angled light" return (HAL) and "low-angled light" return (LAL) for red and green, respectively, be okay? I think this accuracy of language might even aid interpretation when ASET images, CG ASET's, and real images get loaded.

 

[Rockdiamond]

I think we all agree - yet still with different takes on the implications.
Bryan's point ( bolded below) is a very good one. Yes, the ASET offers a repeatable environment- but I've always had an issue with the concept of the operative assumption Bryan mentioned below. In fact, its rare when I'm looking at a diamond that the brightest light is directly overhead. And yes, I am hyper sensitive after years of participation here where that operative assumption seems to be written in stone.

I tend to abandon threads where people are using similar vocabulary but seem to insist on playing different games: If one person applies NFL rules and another applies CFL rules the fundamental length of the field is a contradiction. So, while discussion using football terms and ideas is happening, no consensus can happen because the playing fields are ultimately different. In such threads heads still pound bricks over fundamentals many pages later.

I would like to feel no one is dissembling. In that spirit:

Here's why I feel charts like the one posted go against a balanced discussion- it seems like MORE intense somehow sounds "better" or more desirable than LESS intense.

More is more.

Alcohol proof is a measure of how much alcohol (ethanol) is contained in an alcoholic beverage. In the United States, alcohol content is measured in terms of the percentage of alcohol by volume:

100% ABV (200 proof) is the MOST intoxicating.
80% ABV (160 proof) is LESS intoxicating.

ASET shows where a diamond is returning or not returning light to a viewer's eyes. In this standardized and repeatable environment, given lighting-from-overhead, with 30-40 degrees from high sources blocked by head/body:

RED (drawn from 45-75 degrees) is the most intense light seen by the viewer's eyes.
GREEN (drawn from 0-25 degrees) is less intense.

More is more: 200 proof is the most intoxicating ABV. And RED is the most intense light return seen in ASET.

What's "better" is a matter of context and taste. But as a fundamental baseline of discussion - whether moonshine or diamond-shine - I submit that more simply means more in the repeatable structured environment being discussed in this thread.

JP,
methinks it must be 5 o'clock where you are! How else would you be inspired to such a brilliant analogy. Red and green are both good, as are moonshine and diamond-shine! Just different.

One other thing that I will point out is that the operative assumption is that our world is generally lit from above. In lighting environments where the brightest light source is further down on the horizon (such as a room lit with sconces and no overhead) the brightest light would actually be represented by green.

So, knowing something about light return in terms of the angular spectrum can help you to predict a diamonds appearance in different lighting scenarios.

 

[Rockdiamond]

JP,
methinks it must be 5 o'clock where you are! How else would you be inspired to such a brilliant analogy. Red and green are both good, as are moonshine and diamond-shine! Just different.

One other thing that I will point out is that the operative assumption is that our world is generally lit from above. In lighting environments where the brightest light source is further down on the horizon (such as a room lit with sconces and no overhead) the brightest light would actually be represented by green.

So, knowing something about light return in terms of the angular spectrum can help you to predict a diamonds appearance in different lighting scenarios.

I think the bolded portion is critical: "more intense" and "less intense" are contextual to the lighting environment, which is what we are trying to control for by using ASET's in the first place.

What is the problem with just saying what red and green represent? Would "high-angled light" return (HAL) and "low-angled light" return (LAL) for red and green, respectively, be okay? I think this accuracy of language might even aid interpretation when ASET images, CG ASET's, and real images get loaded.

YES!!! The terms you've created, HAL and LAL would be far less prejudicial than the current use of words.

John- you're in the Christmas spirit already?
Was it 200 proof?

 

[John P]

The front of any AGSL presentation on Angular Spectrum Evaluation cites this: "Even though light can come from any direction, our world is lit from above."

That is the premise of ASET evaluation. It's also the way pros have graded, traded and retailed diamonds.

No diamond dealer runs into a room with side-lighting to "do a deal" on a diamond, whether fancy or round. They're examined in the face-up position with lighting coming from windows - gathering high northern daylight in old-school bourses - or from normal office lighting and fluorescent grading lamps. The GIA observation-studies used a different obstruction metric than AGSL (which is why we have the steep-deep area) but all observations were done with the diamond lit from above. Every pixel-counter (GemEx, Imagem, ISEE, etc.) make judgments in the static face-up position with light from above.

It's the same downstream for sellers, with light added to promote dispersion and scintillation. You don't see Tiffany or Zales killing their overheads and installing sconces. For that matter, to be "lit from the side" as our world is usually lit from above you would need to install point-source lighting like flashlights beaming straight at the diamond from hip-level...or at least bright fluorescents around the perimeter of the room. The mentioned "sconces" diffuse light and kick it up to the ceiling so it also reflects downward. So while those environments might equalize red and green, or provide a slight edge to lower-angled light, they're not as intense or as common in a world that is largely (as AGSL qualifies for ASET studies) lit from above.

 

[Texas Leaguer]

I see nothing wrong with acknowledging that our modern world is generally lit from above, and that therefore red will generally represent the brightest light. That is a pretty common sense notion to me. However, it is important to understand that sometimes diamonds will walk into different lighting environments. Whether you call Red 'bright" or "HAL" in no way diminishes the value of understanding how the diamond is processing the light. And frankly, it seems a bit silly to argue about that.

What is more important, and what I thought the point of this thread was about, is to see different fancy shapes and learn something about the translation of their ASET signatures into real world understanding of their appearance and eye-appeal in a range of lighting scenarios.

That is what I was personally hoping for, rather than this seemingly endless discussion about supposedly "subjective" terminology.
Do we really have to use acronyms in order to accommodate one poster. Or else what? He will drop out of the discussion?

 

[Texas Leaguer]

The front of any AGSL presentation on Angular Spectrum Evaluation cites this: "Even though light can come from any direction, our world is lit from above."

That is the premise of ASET evaluation. It's also the way pros have graded, traded and retailed diamonds.

No diamond dealer runs into a room with side-lighting to "do a deal" on a diamond, whether fancy or round. They're examined in the face-up position with lighting coming from windows - gathering high northern daylight in old-school bourses - or from normal office lighting and fluorescent grading lamps. The GIA observation-studies used a different obstruction metric than AGSL (which is why we have the steep-deep area) but all observations were done with the diamond lit from above. Every pixel-counter (GemEx, Imagem, ISEE, etc.) make judgments in the static face-up position with light from above.

It's the same downstream for sellers, with light added to promote dispersion and scintillation. You don't see Tiffany or Zales killing their overheads and installing sconces. For that matter, to be "lit from the side" as our world is usually lit from above you would need to install point-source lighting like flashlights beaming straight at the diamond from hip-level...or at least bright fluorescents around the perimeter of the room. The mentioned "sconces" diffuse light and kick it up to the ceiling so it also reflects downward. So while those environments might equalize red and green, or provide a slight edge to lower-angled light, they're not as intense or as common in a world that is largely (as AGSL qualifies for ASET studies) lit from above.

Point well taken. I should have said gas lamps.

 

[Rockdiamond]

The front of any AGSL presentation on Angular Spectrum Evaluation cites this: "Even though light can come from any direction, our world is lit from above."

That is the premise of ASET evaluation. It's also the way pros have graded, traded and retailed diamonds.
Actually not John- when grading a diamond the brightest light is NOT entering directly through the table- the grading lamp is at an angle so that light is entering though the pavilion and crown facets- and even the girdle. The loupe is directly in front of the table of the diamond

No diamond dealer runs into a room with side-lighting to "do a deal" on a diamond, whether fancy or round. They're examined in the face-up position with lighting coming from windows - gathering high northern daylight in old-school bourses - or from normal office lighting and fluorescent grading lamps. The GIA observation-studies used a different obstruction metric than AGSL (which is why we have the steep-deep area) but all observations were done with the diamond lit from above. Every pixel-counter (GemEx, Imagem, ISEE, etc.) make judgments in the static face-up position with light from above.

It's the same downstream for sellers, with light added to promote dispersion and scintillation. You don't see Tiffany or Zales killing their overheads and installing sconces. For that matter, to be "lit from the side" as our world is usually lit from above you would need to install point-source lighting like flashlights beaming straight at the diamond from hip-level...or at least bright fluorescents around the perimeter of the room. The mentioned "sconces" diffuse light and kick it up to the ceiling so it also reflects downward. So while those environments might equalize red and green, or provide a slight edge to lower-angled light, they're not as intense or as common in a world that is largely (as AGSL qualifies for ASET studies) lit from above.

In terms of what stores are using, I agree- but what about when the consumer opens the box at home?
When we buy diamonds, as you've seen John, there's plenty of HAL- however I am always taking the diamond to other parts of the room to see how it behaves arm's length. And of course, a traditional grading type exam where the light is NOT perpendicular to the table.

 

[Karl_K]

It is a weakness of ASET that it was designed for MRB's.
It is a fact that the modern RB has reduced off axis light performance compared to other designs and many older designs.
It is to the point that many people when viewing RBs will turn of axis lighting into on axis lighting by turning the table parallel to the lighting.
When they see a diamond with a high level of off axis lighting they are surprised and often pleased.
Frankly the 2 most common cuts MRBs and princess are relatively ineffective at returning low angle lighting.
ASET rewards this.

 

[Rockdiamond]

I see nothing wrong with acknowledging that our modern world is generally lit from above, and that therefore red will generally represent the brightest light. That is a pretty common sense notion to me. However, it is important to understand that sometimes diamonds will walk into different lighting environments. Whether you call Red 'bright" or "HAL" in no way diminishes the value of understanding how the diamond is processing the light. And frankly, it seems a bit silly to argue about that.

What is more important, and what I thought the point of this thread was about, is to see different fancy shapes and learn something about the translation of their ASET signatures into real world understanding of their appearance and eye-appeal in a range of lighting scenarios.

That is what I was personally hoping for, rather than this seemingly endless discussion about supposedly "subjective" terminology.
Do we really have to use acronyms in order to accommodate one poster. Or else what? He will drop out of the discussion?

Hi Bryan,
How about having another professional question these assumptions? You've got just about every pro here singing in perfect harmony- like everyone has drank the same kool aid.
Yet Stan and I feel very differently than most pros posting here- and we're by no means the only pros who feel this way.
Yes, I stick out- because I don't find the discussion balanced- in large part due to pejorative terminology and charts.

NO worries, I'm not running away from the discussion
I'm waiting to find a time when Stan and I can sit down to pick some stones together s we can get to more "meat" of the discussion.
Hopefully later this week

 

[teobdl]

Sorry for feeding the beast, so to speak, but frankly there are many real life situations when the brightest light source is not above 45 degrees above parallel. Often, the diamond is tipped away from overhead light: for example, if one were to rest their hands on the table, the wrist naturally falls at about a 45 degree angle, meaning the high angles return points are pointed away from the light source. Another common scenario is side lighting: watching TV, people often turn off the overhead lights and turn on a lower side table lamp. These are not uncommon situations, and they need to be accounted for. T

I realize I am very green, pun in intended, to the topic. It's why I began the discussion, and I do hope it can still be fruitful. But the issue of language is an important one. It's not nearly as accurate to say green=less bright when it's completely contextual, and this particular context is not nearly as ubiquitous as it's being presumed.

 

[Karl_K]

Hi Bryan,
How about having another professional question these assumptions? You've got just about every pro here singing in perfect harmony- like everyone has drank the same kool aid.

rofl not really, there is a lot we don't all agree on, forum posts are just too clumsy to hash it out.
I understand ASET its strengths and its shortcomings and still find it useful.
There is an old saying don't thrown the baby out with the bath water.....

 

[Karl_K]

Sorry for feeding the beast, so to speak, but frankly there are many real life situations when the brightest light source is not above 45 degrees above parallel. Often, the diamond is tipped away from overhead light: for example, if one were to rest their hands on the table, the wrist naturally falls at about a 45 degree angle, meaning the high angles return points are pointed away from the light source. Another common scenario is side lighting: watching TV, people often turn off the overhead lights and turn on a lower side table lamp. These are not uncommon situations, and they need to be accounted for. T

I realize I am very green, pun in intended, to the topic. It's why I began the discussion, and I do hope it can still be fruitful. But the issue of language is an important one. It's not nearly as accurate to say green=less bright when it's completely contextual, and this particular context is not nearly as ubiquitous as it's being presumed.

I agree with you and that is a point I have made since the first time I saw the particulars of ASET.

 

[Rockdiamond]

Karl- I totally appreciate the open dialog.
Let me as you this..... in your estimation, how many of the tradespeople commonly posting on Pricescope disagree with some, or even many of the assumptions, and or evaluations made by AGSL?

 

[Karl_K]

Karl- I totally appreciate the open dialog.
Let me as you this..... in your estimation, how many of the tradespeople commonly posting on Pricescope disagree with some, or even many of the assumptions, and or evaluations made by AGSL?

I don't know the answer to that but I think its more than you think and more than the ones posting reflect.
The ones that comment on it are generally the ones that have strong leanings one way or the other.
I like discussing it just for fun, intellectual stimulation and once in a while I learn something new :}

 

[Texas Leaguer]

Hi Bryan,
How about having another professional question these assumptions? You've got just about every pro here singing in perfect harmony- like everyone has drank the same kool aid.

rofl not really, there is a lot we don't all agree on, forum posts are just too clumsy to hash it out.
I understand ASET its strengths and its shortcomings and still find it useful.
There is an old saying don't thrown the baby out with the bath water.....

I agree. ASET is not the sole answer to diamond evaluation. It is one good tool to understand potential light behavior.

The "kool aid" refered to is aparently the recognition that the tool indicates different parts of the angular spectrum in particular colors. And by default from an on-axis face up direction. Beyond that, it is all about using that information to come up with understandings about how that relates to diamond beuaty. It is frequently recognized that rounds and princess are fairly well understood in terms of what ASET tells you, but that fancies are much harder to predict. That is the point of this thread. To see examples and hear "expert testimony" as to how interpret various the ASET signatures.

Is it drinking kool aid to agree to the specific angular ranges represented by the different colors in the tool? Or that most of us spend alot of time in offices and buildings and stores and other places that have overhead lighting?

Some of the legitimate issues that have been raised and used as rationale for questioning the usefulness of the tool, for instance off axis viewing, should instead be discussed with the intention of trying to understand what happens to light performance in those different viewing scenarios. And studying ASET images is useful in that regard!

 

[Rockdiamond]

Karl, on the last point, we totally agree.
It's amazing and fun stuff to talk about, and I've leaned a ton over the years.

My experience Karl?
I don't see a lot of people questioning AGSL suppositions- certainly not tradespeople.

GIA cut grading?
Open season on that one.

AGSL cut grading?
Untouchable. It's science.

Comparing the two labs on round diamond cut grading, it's easy to find ways AGSL is superior to GIA.
But that does not extend to Fancy Shapes where we can't even compare the two labs.
The AGSL research that I've read is all about conclusions.
I'm sure that's what many people want.
Red=more
Green=less
We can even call it scientific analysis. Then if someone brings up weak points of the conclusions, we can accuse them of arguing against science.
Sorry, I have some scars leftover from those battles

Anyway, I can't thank teobdl enough for starting the thread, and also for so perfectly expressing this point:

Sorry for feeding the beast, so to speak, but frankly there are many real life situations when the brightest light source is not above 45 degrees above parallel. Often, the diamond is tipped away from overhead light: for example, if one were to rest their hands on the table, the wrist naturally falls at about a 45 degree angle, meaning the high angles return points are pointed away from the light source. Another common scenario is side lighting: watching TV, people often turn off the overhead lights and turn on a lower side table lamp. These are not uncommon situations, and they need to be accounted for. T

I realize I am very green, pun in intended, to the topic. It's why I began the discussion, and I do hope it can still be fruitful. But the issue of language is an important one. It's not nearly as accurate to say green=less bright when it's completely contextual, and this particular context is not nearly as ubiquitous as it's being presumed.

 

[Rockdiamond]

Hi Bryan,
How about having another professional question these assumptions? You've got just about every pro here singing in perfect harmony- like everyone has drank the same kool aid.

rofl not really, there is a lot we don't all agree on, forum posts are just too clumsy to hash it out.
I understand ASET its strengths and its shortcomings and still find it useful.
There is an old saying don't thrown the baby out with the bath water.....

I agree. ASET is not the sole answer to diamond evaluation. It is one good tool to understand potential light behavior.

The "kool aid" refered to is aparently the recognition that the tool indicates different parts of the angular spectrum in particular colors. And by default from an on-axis face up direction. Beyond that, it is all about using that information to come up with understandings about how that relates to diamond beuaty. It is frequently recognized that rounds and princess are fairly well understood in terms of what ASET tells you, but that fancies are much harder to predict. That is the point of this thread. To see examples and hear "expert testimony" as to how interpret various the ASET signatures.

Is it drinking kool aid to agree to the specific angular ranges represented by the different colors in the tool? Or that most of us spend alot of time in offices and buildings and stores and other places that have overhead lighting?

Some of the legitimate issues that have been raised and used as rationale for questioning the usefulness of the tool, for instance off axis viewing, should instead be discussed with the intention of trying to understand what happens to light performance in those different viewing scenarios. And studying ASET images is useful in that regard!

Bryan- I respect you, and the way your company represents diamonds- it's exceptional, really.
I have thought a lot about this- and I am pretty sure you have as well.
We all have different perspectives due to the different positions we all occupy.
Stan, Paul and Yoram can give us cutter's perspective. Gary and Serg have been at the forefront in introducing technologies to assist consumers- and advance the cutter's art.
You can feel the effects of this debate when people ask for ASETs, post them here, and get readings based on AGSL suppositions.
My position, as a seller is this: if you allow ASET images to control the diamonds you offer- as opposed to picking stones that appeal to you visually, in person, you will get more returns.

In the previous thread, the debate started with a person in the trade repeated the oft repeated mantra.

Red – Great
Green – Good
Blue – Necessary and desired (esp. if balanced and symmetrical)
Leakage – Bad.

Some of the tradespeople posting here learned this sort of thing right here. It's simply not good advice for many buyers.

Anyway, we're on the same side man!
We both want to increase consumer satisfaction and reduce returns.
Better ASET interpretations will do that.
Peace

 

[Garry H (Cut Nut)]

While I am sleeping you guys have been at it

It is a weakness of ASET that it was designed for MRB's.
It is a fact that the modern RB has reduced off axis light performance compared to other designs and many older designs.
It is to the point that many people when viewing RBs will turn of axis lighting into on axis lighting by turning the table parallel to the lighting.
When they see a diamond with a high level of off axis lighting they are surprised and often pleased.
Frankly the 2 most common cuts MRBs and princess are relatively ineffective at returning low angle lighting.
ASET rewards this.

Karl I agree, and taking emerald cuts and asschers for example - I always want to have lots of blue, that flashes on and off as I rotate the diamond or the DiamCalc image.

David, In that respect I disagree strongly with AGSL's approach - where they seem to be applying RBC technology to the wrong cut. They are not the final arbiter in this field. They are a work in progress, like the rest of 'us'.

Regarding consistent ASET images, I think its pretty much a no brainer that our DiBox is the system of choice for reproduceable ASET (and other) images. There are several in USA now and I am sure some of those owners would be agreeable to snapping off some shots if asked nicely - most of the owners participate here anyway.

Finally, no one seems to be mentioning fancy coloured ASET - its the clasic example that John refers to as "in context", and here is an example of an ASET for a fancy colour - its not the best example - just one that I opened a few minutes ago. Its a DiamCalc from a bad scan.
The top image is from DiamCalc, middle is a vendor photo with no backlight, and below is the AGS digital ASET. It would be great to have an example with a good photo too?

 

[Rockdiamond]

This is amazing- we are finding a lot of common ground.
Love it!
Garry- question- the AGS digital image appears to be a different model ( overall shape) than the vendor photo or the diamcalc
Is this just a photo resize issue, or a problem with the AGSL system?

 

[Garry H (Cut Nut)]

This is amazing- we are finding a lot of common ground.
Love it!
Garry- question- the AGS digital image appears to be a different model ( overall shape) than the vendor photo or the diamcalc
Is this just a photo resize issue, or a problem with the AGSL system?

No idea David. But I did a screen capture of the top one the DC image and this screen does not show round as round - so probably me - but they are all the same stone I assure you.

 

[Rockdiamond]

This is amazing- we are finding a lot of common ground.
Love it!
Garry- question- the AGS digital image appears to be a different model ( overall shape) than the vendor photo or the diamcalc
Is this just a photo resize issue, or a problem with the AGSL system?

No idea David. But I did a screen capture of the top one the DC image and this screen does not show round as round - so probably me - but they are all the same stone I assure you.

I wasn't questioning that aspect at all!
Rather the software that generated the image.
The Diamcalc seems far closer to the photo in every way.

But if we are including Fancy Colored Diamonds....making it even more interesting.....
Would you agree that in the context of Fancy Colored Diamonds, leakage is desirable. The right leakage of course, but leakage is an essential element in color retention and broadcasting in a majority of FCD's- are we agreed on that?

In that regard, maybe the AGSL is just showing too much of that aspect, while the Diamcalc is giving a more balanced view.

 

[Karl_K]

But if we are including Fancy Colored Diamonds....making it even more interesting.....
Would you agree that in the context of Fancy Colored Diamonds, leakage is desirable. The right leakage of course, but leakage is an essential element in color retention and broadcasting in a majority of FCD's- are we agreed on that?

That is not true all the time I don't think, drawing light from pavilion(leakage) can wash out color.
It just so happens that the best angles to increase color are close to those that draw light from the pavilion.
So sometimes you get some of both.
You sometimes can improve the color by increasing the "leakage" because the increase is bigger than the color being washed out I would assume. On the other hand you might be able to increase the color by having less "leakage". Other times you might get a more even color by allowing some "leakage".
It is more complex than saying "leakage" is good or bad for color.
I am not an expert on cutting/designing for color but that is what I have found in my studies.
Serg may come along and prove me wrong however. lol

 

[Texas Leaguer]

While I am sleeping you guys have been at it

It is a weakness of ASET that it was designed for MRB's.
It is a fact that the modern RB has reduced off axis light performance compared to other designs and many older designs.
It is to the point that many people when viewing RBs will turn of axis lighting into on axis lighting by turning the table parallel to the lighting.
When they see a diamond with a high level of off axis lighting they are surprised and often pleased.
Frankly the 2 most common cuts MRBs and princess are relatively ineffective at returning low angle lighting.
ASET rewards this.

Karl I agree, and taking emerald cuts and asschers for example - I always want to have lots of blue, that flashes on and off as I rotate the diamond or the DiamCalc image.

David, In that respect I disagree strongly with AGSL's approach - where they seem to be applying RBC technology to the wrong cut. They are not the final arbiter in this field. They are a work in progress, like the rest of 'us'.

Regarding consistent ASET images, I think its pretty much a no brainer that our DiBox is the system of choice for reproduceable ASET (and other) images. There are several in USA now and I am sure some of those owners would be agreeable to snapping off some shots if asked nicely - most of the owners participate here anyway.

Finally, no one seems to be mentioning fancy coloured ASET - its the clasic example that John refers to as "in context", and here is an example of an ASET for a fancy colour - its not the best example - just one that I opened a few minutes ago. Its a DiamCalc from a bad scan.
The top image is from DiamCalc, middle is a vendor photo with no backlight, and below is the AGS digital ASET. It would be great to have an example with a good photo too?

Garry,
A question and a couple of comments.
What do you make of the large discrepancy between the DC and AGS ASET maps? Significantly more light return in top image.

Fancy colored diamonds are a different animal altogether than diamonds in the normal range from a cutting perspective. Therefore the ASET interpretations will be entirely different. In a FCD the cutter is aiming primarily for color and weight retention. The color call on the cert and carat weight will largely determine the value of the diamond. Therefore one might come to the conclusion from looking at ASET that this is a very well cut stone in the sense that brightness is damped down that would otherwise diminish the aparent color, and light is being drawn from the pavilion, which may help the color and assist in being able to enhance aparent color in setting by using a strategically closed and colored back.

These same techniques used on a diamond in the normal range would largely negate the beauty aspects important to value and sellability.