ASETs and fancy cuts

[teobdl]

A number of trades people have recently remarked about the limitations of using ASET in fancies, and that many PS consumers are inappropriately guided by incomplete or even incorrect perceptions of what can or cannot be learned from ASET's.

With PS consumers' best interests in mind, I'm digging up this thread as a basis for discussing what we can and cannot learn from ASETs when evaluating fancy cuts, and the appropriate use of ASET in rejection or selection. [URL='https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/']https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/[/URL]

From more recent discussions, I am beginning to think that fancies can only be chosen on the basis of what the consumer's eyes prefer (or a very experienced, trusted vendor) in real life.

My first, very basic, question is this: why would a consumer want to see an ASET?

 

[Karl_K]

Because it provides useful information.
More than anything it provides me a starting point at what to look at in the other information.
If given a choice I would rather have a real video not just flashing static pics vs ASET.
But even with a good video the ASET gives me ideas of what to look at specifically in the video.
It is not a magic wand but it is useful.
I would rather have than not when looking for diamonds online.

In person it changes a little, as you learn more about diamonds and see more diamonds an ASET becomes less useful but again it does give you hints on what to pay attention too and can quickly sort out the ones with the most potential for me to look at closer.

For example lets say ASET shows a large blue band under the table, when viewing it in person it tells me to pay attention to that area as it may or may not be a problem.

 

[drk14]

My first, very basic, question is this: why would a consumer want to see an ASET?

Consumer here (beginner level).

I've been following the recent ASET debates with great interest, as I'm currently in the market for a fancy cut.

I'm currently waiting on ASETs, and I'm not sure exactly how I will end up using them. I imagine they will allow me to rule out stones with optical performance that is extremely sub-par (say < 1-2 sigma below "average"), but I definitely do not plan to take any "rules of thumb" (e.g., excluding stones with blue bowties, preferring red to green, etc.) as gospel.

I also have a follow-up question: Couldn't an ASET be of great value to a jeweler who is designing a setting for a fancy stone? For example, to plan the placement of metal for the prongs/basket, as well as the sidestones, to synergistically interact with the light performance characteristics of the center stone? Do any designers out there currently use ASETs in this way? (and if so, who are they? )

 

[TURNER430]

Well this is odd, I was just about to post ASET and Idealscope images of a Pear Cut diamond . I know fancies are difficult when it comes to these things, I was just hoping that anyone could point out any showstoppers from them.

Anyone mind if I hijack the thread a bit and post the images? Could help illustrate the point a bit for us amateurs.

 

[Karl_K]

Well this is odd, I was just about to post ASET and Idealscope images of a Pear Cut diamond . I know fancies are difficult when it comes to these things, I was just hoping that anyone could point out any showstoppers from them.

Anyone mind if I hijack the thread a bit and post the images? Could help illustrate the point a bit for us amateurs.

please post them in a new thread and if you like link it here.
Due to forum rules experts may not be able to comment if it becomes about specific stones.

 

[John P]

I'm largely with Karl on this. ASET is a correlation tool. Of course, that means one must make correlations to use it.

Let's start with real-life. Everyone agrees that real-life examination is the most decisive. Full Stop.

But anyone who limits real-life viewing to a single lighting environment will get only one impression, and won't understand a diamond's range of performance. And anyone who doesn't correlate the observations to the diamond's parameters won't learn how to predict performance based on data. So the best diamond professionals max-out both things. First, they observe any given diamond through multiple lighting conditions, noting all pros and cons. Second, they always (always!) correlate those observations with the diamond's parameters... FWIW, I record parameters after observing & noting, not before ...Third, they observe, note and correlate diamonds every day, not just on their 'home-turf' but in other places, to calibrate themselves for consistency.

Over time a professional can estimate a diamond's proportion-parameters simply from naked-eye observation through a range of lighting. I do this "parlor-trick" in stores where I train staff, and make them try it too. They think I'm oh-so witty, but I'm not. It's simply lots and lots of practice. When I apply ASET to the observations above, WOW, what a great correlation-tool I have.

Now let's reverse-engineer the process. For rounds it's especially reliable. I've done so much work with rounds and princess cuts in real-life, and have become so familiar with how XYZ paremeters pan-out, that I'm quite comfortable making interpretations from an ASET and a grading report. For more complex and variable fancies it gets harder. The qualifier here is the need to reverse-engineer; meaning the most important component to ASET interpretation with fancies is prior live correlation.

So for hobbyists who never see diamonds ASET theory and interpretation can still be useful with round brilliants, as there's reliable consistency in "reading" particulars of brightness, contrast and leakage. For diamond pros who make daily correlations of diamonds to ASET it's certain that even more can be intuited. But complex fancy shapes are different, even for pros. And for hobbyists who haven't made regular (daily/abundant/diverse) correlations to real-life viewing it's possible to misinterpret or "read too much" into a fancy ASET image.

 

[Karl_K]

Well said Sir John!

 

[Serg]

A number of trades people have recently remarked about the limitations of using ASET in fancies, and that many PS consumers are inappropriately guided by incomplete or even incorrect perceptions of what can or cannot be learned from ASET's.

With PS consumers' best interests in mind, I'm digging up this thread as a basis for discussing what we can and cannot learn from ASETs when evaluating fancy cuts, and the appropriate use of ASET in rejection or selection. [URL='https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/']https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/[/URL]

From more recent discussions, I am beginning to think that fancies can only be chosen on the basis of what the consumer's eyes prefer (or a very experienced, trusted vendor) in real life.

My first, very basic, question is this: why would a consumer want to see an ASET?

ASET is very effective Quality Control tool. It is helpful( fast, easy , cheap) to detect difference between Sample and Current diamond.( both have to have same cut)

if somebody found , selected nice Sample diamonds( according some rules, Taste,..) then ASET is very effective tool to find similar diamonds.

 

[Texas Leaguer]

I agree with what has been said so far. Fancies are more complicated. Therefore, they are harder to analyze from afar. I actually think that makes tools like ASET more valuable. If you are trying to identify diamonds to bring in and look at, you need to acquire all the information you can.

While no single tool gives you all the information you need , looking at an ASET map tells you important things about how the diamond is handling light, and like Karl says, points you to things to look for in further evaluations.

Each of the tools has limitations. Like John suggested, even looking at the diamond in real life can be misleading if you don't see it in different lighting environments!

The ASET tool is integral to the AGS light performance grading system. ASET signatures are significantly different for each shape and facet configuration and they are very different from rounds in most cases. The market is most familiar with round and to some extent princess signatures and can interpret them with pretty good accuracy. Many fancy shapes are uncharted territory and require the experts who specialize in them to educate the market in the proper interpretation. I think that is happening and our collective understanding here will continue to evolve.

 

[MelisendeDiamonds]

A number of trades people have recently remarked about the limitations of using ASET in fancies, and that many PS consumers are inappropriately guided by incomplete or even incorrect perceptions of what can or cannot be learned from ASET's.

My first, very basic, question is this: why would a consumer want to see an ASET?

Teobdl I can see you are one of the more studious pricescopers, who demonstrates effort and reading of past threads in an attempt to learn, so I thank-you for asking this on point question.

My answer is for the consumer to be able to highlight the significant differences in potential brightness between the right and the left types of cutting styles.



The comments you have read by trade including mine should be taken into proper context. https://www.pricescope.com/communit...-view-a-diamond.203839/#post-3710458#p3710458

"Most fancy cuts are not designed with a primary emphasis on returning high angle light back to the viewer from edge to edge like a round brilliant. Other factors such as outline shape, spread, scintillation pattern, yield, and colour are given more equal consideration in this cutting style."

I'd still want to see the ASET images of any Fancy shape especially if I couldn't view the stone in hand, but the subjective overall assessment including the ASET data should properly take into account the tradeoffs, between spread, weight saving(and price saving), and potential brightness for most fancy shapes most especially with radiants, princess, cushions, pears, marquise.

What concerns me most is when a consumer is faced with choosing between 3 mediocre cut Fancy outline diamonds in terms of brightness and chooses the one with the seemingly "best" ASET image while ignoring most of the other diamond characteristics as they cannot see the diamonds in front of them. In a case like this reliance on ASET for selection could lead to a poor choice and perhaps all three are unsuitable and a better choice which better fits that consumer's preferences better can be made elsewhere with a different selection method.

I don't however throw out the use of this extremely valuable tool as it empowers consumers to make objective comparisons on the basis of brightness, which can be quite useful for internet shopping. If the the sales and marketing efforts of a particular brand or vendor gets in the way of a clear understanding of the brightness differences between the stones above than I think discrediting the tools and comparisons is disingenuous and contrary to a fair and balanced consumer education which I think is what is being sought out on these forums.

 

[Karl_K]

This image posted above shows an important point.
ASET is good for separating the stone on the left from the 2 on the right.
It however is not a very good tool for picking between the 2 on the right.
Which is one reason I use ASET more as pass/fail and to find areas of the diamond to look into further.

 

[MelisendeDiamonds]

This image posted above shows an important point.
ASET is good for separating the stone on the left from the 2 on the right.
It however is not a very good tool for picking between the 2 on the right.
Which is one reason I use ASET more as pass/fail and to find areas of the diamond to look into further.

Yes I agree with you and that was the reason for the image. I also selected the top right stone to dispel the idea that ASET can only be applied to "round" like performing stones.

 

[Texas Leaguer]

This image posted above shows an important point.
ASET is good for separating the stone on the left from the 2 on the right.
It however is not a very good tool for picking between the 2 on the right.
Which is one reason I use ASET more as pass/fail and to find areas of the diamond to look into further.

Yes I agree with you and that was the reason for the image. I also selected the top right stone to dispel the idea that ASET can only be applied to "round" like performing stones.

Good stuff!
It would be great to hear detailed descriptions of the samples in terms of visual characteristics, eye appeal, how they look in different lighting environments, pluses/minuses, etc.. The real world observations combined with the ASET maps would go a long way to improving our ability to properly interpret the ASET signatures.

 

[Karl_K]

Good stuff!
It would be great to hear detailed descriptions of the samples in terms of visual characteristics, eye appeal, how they look in different lighting environments, pluses/minuses, etc.. The real world observations combined with the ASET maps would go a long way to improving our ability to properly interpret the ASET signatures.

That would be good for someone to do. The diamonds would have to be in hand to do it.
It would have to be a journal article for a trade member to do it and stay within the rules.

 

[Serg]

A number of trades people have recently remarked about the limitations of using ASET in fancies, and that many PS consumers are inappropriately guided by incomplete or even incorrect perceptions of what can or cannot be learned from ASET's.

My first, very basic, question is this: why would a consumer want to see an ASET?

Teobdl I can see you are one of the more studious pricescopers, who demonstrates effort and reading of past threads in an attempt to learn, so I thank-you for asking this on point question.

My answer is for the consumer to be able to highlight the significant differences in potential brightness between the right and the left types of cutting styles.

ASET may mislead consumer even in such choice.

See example of Nice ASET Image for very bad cut( BTW. it is 10 years old example )






The comments you have read by trade including mine should be taken into proper context. https://www.pricescope.com/communit...-view-a-diamond.203839/#post-3710458#p3710458

"Most fancy cuts are not designed with a primary emphasis on returning high angle light back to the viewer from edge to edge like a round brilliant. Other factors such as outline shape, spread, scintillation pattern, yield, and colour are given more equal consideration in this cutting style."

I'd still want to see the ASET images of any Fancy shape especially if I couldn't view the stone in hand, but the subjective overall assessment including the ASET data should properly take into account the tradeoffs, between spread, weight saving(and price saving), and potential brightness for most fancy shapes most especially with radiants, princess, cushions, pears, marquise.

What concerns me most is when a consumer is faced with choosing between 3 mediocre cut Fancy outline diamonds in terms of brightness and chooses the one with the seemingly "best" ASET image while ignoring most of the other diamond characteristics as they cannot see the diamonds in front of them. In a case like this reliance on ASET for selection could lead to a poor choice and perhaps all three are unsuitable and a better choice which better fits that consumer's preferences better can be made elsewhere with a different selection method.

I don't however throw out the use of this extremely valuable tool as it empowers consumers to make objective comparisons on the basis of brightness, which can be quite useful for internet shopping. If the the sales and marketing efforts of a particular brand or vendor gets in the way of a clear understanding of the brightness differences between the stones above than I think discrediting the tools and comparisons is disingenuous and contrary to a fair and balanced consumer education which I think is what is being sought out on these forums.

 

[Rockdiamond]

I'm largely with Karl on this. ASET is a correlation tool. Of course, that means one must make correlations to use it.

Let's start with real-life. Everyone agrees that real-life examination is the most decisive. Full Stop.

But anyone who limits real-life viewing to a single lighting environment will get only one impression, and won't understand a diamond's range of performance. And anyone who doesn't correlate the observations to the diamond's parameters won't learn how to predict performance based on data. So the best diamond professionals max-out both things. First, they observe any given diamond through multiple lighting conditions, noting all pros and cons. Second, they always (always!) correlate those observations with the diamond's parameters... FWIW, I record parameters after observing & noting, not before ...Third, they observe, note and correlate diamonds every day, not just on their 'home-turf' but in other places, to calibrate themselves for consistency.

Over time a professional can estimate a diamond's proportion-parameters simply from naked-eye observation through a range of lighting. I do this "parlor-trick" in stores where I train staff, and make them try it too. They think I'm oh-so witty, but I'm not. It's simply lots and lots of practice. When I apply ASET to the observations above, WOW, what a great correlation-tool I have.

Now let's reverse-engineer the process. For rounds it's especially reliable. I've done so much work with rounds and princess cuts in real-life, and have become so familiar with how XYZ paremeters pan-out, that I'm quite comfortable making interpretations from an ASET and a grading report. For more complex and variable fancies it gets harder. The qualifier here is the need to reverse-engineer; meaning the most important component to ASET interpretation with fancies is prior live correlation.

So for hobbyists who never see diamonds ASET theory and interpretation can still be useful with round brilliants, as there's reliable consistency in "reading" particulars of brightness, contrast and leakage. For diamond pros who make daily correlations of diamonds to ASET it's certain that even more can be intuited. But complex fancy shapes are different, even for pros. And for hobbyists who haven't made regular (daily/abundant/diverse) correlations to real-life viewing it's possible to misinterpret or "read too much" into a fancy ASET image.

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

 

[MelisendeDiamonds]

Good stuff!
It would be great to hear detailed descriptions of the samples in terms of visual characteristics, eye appeal, how they look in different lighting environments, pluses/minuses, etc.. The real world observations combined with the ASET maps would go a long way to improving our ability to properly interpret the ASET signatures.

That would be good for someone to do. The diamonds would have to be in hand to do it.
It would have to be a journal article for a trade member to do it and stay within the rules.

Why does it have to be a journal article? I have scans of all three of these types of diamonds if it helps. These are old and were not sold by us but I can compare the three types of cut cornered square brilliants.

 

[Karl_K]

Good stuff!
It would be great to hear detailed descriptions of the samples in terms of visual characteristics, eye appeal, how they look in different lighting environments, pluses/minuses, etc.. The real world observations combined with the ASET maps would go a long way to improving our ability to properly interpret the ASET signatures.

That would be good for someone to do. The diamonds would have to be in hand to do it.
It would have to be a journal article for a trade member to do it and stay within the rules.

Why does it have to be a journal article? I have scans of all three of these types of diamonds if it helps. These are old and were not sold by us but I can compare the three types of cut cornered square brilliants.

To do what was ask for and needed requires the diamonds in hand and potentially for sale, that would be against the rules for self promotion for the forum, however it would be allowed in the journal as an educational article.

 

[Ella]

Good stuff!
It would be great to hear detailed descriptions of the samples in terms of visual characteristics, eye appeal, how they look in different lighting environments, pluses/minuses, etc.. The real world observations combined with the ASET maps would go a long way to improving our ability to properly interpret the ASET signatures.

That would be good for someone to do. The diamonds would have to be in hand to do it.
It would have to be a journal article for a trade member to do it and stay within the rules.

Why does it have to be a journal article? I have scans of all three of these types of diamonds if it helps. These are old and were not sold by us but I can compare the three types of cut cornered square brilliants.

To do what was ask for and needed requires the diamonds in hand and potentially for sale, that would be against the rules for self promotion for the forum, however it would be allowed in the journal as an educational article.

We could also allow an exception this time for this clearly educational purpose if someone had scans of stones that were previously sold.

 

[Rockdiamond]

Great thread!
Thank you teobdl for posting it.
I have been speaking to Stan ( Radiantman) and we would love to participate.
Stan has the OGI machine, and we're currently finding out how to produce CG asets using the OGI.
This is more reliable than trying to take pictures.

Stan and I will look at stones together and pick samples we find to have the qualities we love in scintillation, spread brilliance- and overall appearance.
We'll run scans, post ASETS- and I'll take actual photos of the stones to post.
We can both give our real life impressions as well.

 

[Karl_K]

Great thread!
Thank you teobdl for posting it.
I have been speaking to Stan ( Radiantman) and we would love to participate.
Stan has the OGI machine, and we're currently finding out how to produce CG asets using the OGI.
This is more reliable than trying to take pictures.

Stan and I will look at stones together and pick samples we find to have the qualities we love in scintillation, spread brilliance- and overall appearance.
We'll run scans, post ASETS- and I'll take actual photos of the stones to post.
We can both give our real life impressions as well.

sounds kewl
just make sure and look at the stone under your ASET scope to make sure the scan based images are reasonably accurate. Some likely wont be.

 

[Rockdiamond]

Interesting point Karl!
My trepidation with taking ASET pics are due to the fact it's so easy to mess it up

Doesn't AGSL use CG ASET images?

 

[Karl_K]

Interesting point Karl!
My trepidation with taking ASET pics are due to the fact it's so easy to mess it up

Doesn't AGSL use CG ASET images?

yes they use scan based computer generated images.
Some are pretty messed up compared to real images.
You can use generated images its just a good idea to verify them and label them as such.

 

[Garry H (Cut Nut)]

Great thread!
Thank you teobdl for posting it.
I have been speaking to Stan ( Radiantman) and we would love to participate.
Stan has the OGI machine, and we're currently finding out how to produce CG asets using the OGI.
This is more reliable than trying to take pictures.

Stan and I will look at stones together and pick samples we find to have the qualities we love in scintillation, spread brilliance- and overall appearance.
We'll run scans, post ASETS- and I'll take actual photos of the stones to post.
We can both give our real life impressions as well.

Good to hear David,
You can always email the scans to Karl or me and we can reproduce them with DiamCalc for you.
Personally I prefer the definition of the DC over AGSL software.
Mind you I am based as I sell DiamCalc on the IS website.

 

[MelisendeDiamonds]

Great thread!
Thank you teobdl for posting it.
I have been speaking to Stan ( Radiantman) and we would love to participate.
Stan has the OGI machine, and we're currently finding out how to produce CG asets using the OGI.
This is more reliable than trying to take pictures.

Stan and I will look at stones together and pick samples we find to have the qualities we love in scintillation, spread brilliance- and overall appearance.
We'll run scans, post ASETS- and I'll take actual photos of the stones to post.
We can both give our real life impressions as well.

Good to hear David,
You can always email the scans to Karl or me and we can reproduce them with DiamCalc for you.
Personally I prefer the definition of the DC over AGSL software.
Mind you I am based as I sell DiamCalc on the IS website.

A .srn file would be preferable on my side as well so I can compare to the scans I have in same lighting.
However as Karl said I think a photographed image should also be taken to prove that the generated ASET matches the photographed one.

 

[MelisendeDiamonds]

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.

 

[Rockdiamond]

AS I see it, the main issue with photographing is variability.
A myriad of camera issues, as well as stone positioning create inconsistencies.

 

[Rockdiamond]

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.

 

[Texas Leaguer]

Interesting point Karl!
My trepidation with taking ASET pics are due to the fact it's so easy to mess it up

Doesn't AGSL use CG ASET images?

yes they use scan based computer generated images.
Some are pretty messed up compared to real images.
You can use generated images its just a good idea to verify them and label them as such.

The computer generated image is only as good as the scan. A really messed up CG image is likely one where the scan was corrupted in some way.

Having said that, there are virtually ALWAYS some differences between an actual ASET photo taken through a viewer and a computer generated ASET map. The ASET ray tracer that generates the map is constrained to the exact specifications of the theoretical design of the system and calculated mathematically. Therefore it is consistent and repeatable. A key feature is the precise dimension of the viewing hemisphere. Photos on the other hand introduce a number of variables. The adaptations that people have made to be able to take ASET photos only approximate the angular spectrum defined by ASET. And things like variable stone sizes and slight leveling adjustments can affect the outcome as well.

This is not to say that these approximations do not provide very useful results. But in many cases it can be as instructive to compare the computer generated map against the photo to check the validity of the photo. Having both is therefore very informative.

 

[Rockdiamond]

A number of trades people have recently remarked about the limitations of using ASET in fancies, and that many PS consumers are inappropriately guided by incomplete or even incorrect perceptions of what can or cannot be learned from ASET's.

With PS consumers' best interests in mind, I'm digging up this thread as a basis for discussing what we can and cannot learn from ASETs when evaluating fancy cuts, and the appropriate use of ASET in rejection or selection. [URL='https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/']https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/[/URL]

From more recent discussions, I am beginning to think that fancies can only be chosen on the basis of what the consumer's eyes prefer (or a very experienced, trusted vendor) in real life.

My first, very basic, question is this: why would a consumer want to see an ASET?

Melisende- to your point- please look at the premise of the discussion.
Why would a consumer want an ASET?
We can agree how the ASET functions- but not necessarily what the results mean.
If all we're trying to do is get the most intense light we can install little LEDs in rings.
But of course the appeal of a diamond that returns very little light is small.
So we're trying to walk a tightrope, in a sense.
How much intense light, how much spread, how much contrast, how much scintillation?

There's no "right" answer- but we can help people decide what is right for themselves in a more balanced manner IMO