AGSL Scintillation Studies

[JohnQuixote]

 

[JohnQuixote]

Here are a few questions from the other thread that are well-suited for this one.

Date: 6/7/2007 12:43:11 PM
Author: Regular Guy

Reviewing again the graphics on scintillation...my first thought was towards the similarity in gestalt to what we see has been developed with Gemex.

There are significant differences between AGSL and prior approaches, with regard to both fire and scintillation. First, with regard to fire…

Some virtual facets have a higher potential to produce fire than others because some have higher dispersion than others. Just because you see fire in a specific VF in a diamond photo it doesn’t tell you the total fire potential for that facet: A VF with high dispersion could appear white and one with low dispersion could appear colored in a given lighting environment. For example, a VF with low dispersion might be drawing light from the edge of a source, appearing colored, which would be misleading in many cases. This is just one example of the problem with assessing a diamond in a fixed lighting environment (or two, or five, or 25). It’s why AGSL has worked for some years to develop metrics and animations independent from lighting environments.

The AGSL approach to fire is to measure the dispersion of each VF directly via ray-tracing. They are not measuring the quantity/quality of the particular fire observed in one specified environment. They are assessing the potential of each point in the stone to display fire, completely independent of environment. In essence, this is factoring lighting environments out of the equation to provide equal footing to all diamonds regardless of lighting environment.

This difference is very important, since a diamond can be designed to do well in a light-source-dependent environment. Making it independent removes this kind of mechanical bias.

 

[JohnQuixote]

Re: Scintillation...

Date: 6/7/2007 12:43:11 PM
Author: Regular Guy

Date: 6/1/2007 5:03:51 PM
Author: JohnQuixote

The best thing about this system is that it is light source independent - with the exception of the final graphic which is a kind of standardized litmus test.Prior systems fire lights at a diamond and count pixels to arrive at a ‘score.’This metric evaluates scintillation potential.

So question 1 is to ask you to say this a different way. I intuit that we're talking about passive as in ASET style presentations, with light behind...but...just how nuanced is this difference?

Here’s an analogy: Suppose you’ve never played poker before but want to know how often a particular hand is dealt (3 of a kind vs 2 pair for instance).

You deal yourself a dozen hands and count how many times 3 of a kind is dealt vs 2 pair. Then you do it again, but you get a different result. Repeat and you get a third result. It becomes clear that the result is not going to be constant. The more dozens of hands you deal the closer you get to a predictive answer, but you soon realize that any hand dealt is a function of the shuffle (or in our case the lighting environment). For some shuffles 3 of a kind appears more often. For others 2 pair appears more. For some neither appears. This is how a fixed lighting environment works and why labs and experts have rejected systems like GemEx which are ‘weighted’ towards a particular shuffle. In reality, the world’s lighting environments are made up of an infinite number of shuffles.

So…you begin to look for a better way of knowing how often a certain hand will be dealt in poker. You realize you need a way to analyze the game that is shuffle-independent and will give you the greatest chance of evaluating overall potential. The poker channels do this by calculating the odds for a given results with all possible shuffles considered.

In line with the above, one way to arrive at a scintillation result would be to illuminate the stone in one lighting environment and count the number of sparkles. You could count the white sparkles, colored sparkles, sparkles of various sizes and anything else you can think of related to scintillation. You could then “shuffle” your lighting environment and repeat, over and over again.

AGSL approaches the problem from the other direction. They ask, what is the total number of potential sparkles this stone has when it is tilted along such and such an axis, with all shuffles considered? What is the probability of seeing at least 3 or more sparkles when a x mm light source is randomly placed in the hemisphere? On average how far are these sparkles distributed across the crown of the stone? On average, how large are the sparkles? What are the odds of seeing a sparkle of such and such size? The answers to all of the questions are not calculated from one specific lighting environment, or two, or twenty: They are the results you would get when you consider all possible lighting environments.

Knowing the answers to these questions gives you expectations of what you will likely see in the stone. Considering that the number of the world's lighting environments are closer to infinite than not, decoupling the lighting environment from the metric (as much as possible) seems the way to go. Fortunately, the information now possible by ray tracing the stone allows these sorts of probabilities to be computed, although it’s fried at least one AGSL guru’s computer.

 

[JohnQuixote]

Date: 6/8/2007 7:36:58 AM
Author: Regular Guy

So, here's a follow up. You get 45 shots to make a movie? This is based on 2 degree rotation? What if the sinque is moved over 1 degree, and the shots are still 45 of them, but moved one degree over?

Does this variance map on to the sorts of concerns expressed concerning Gemex (as to the shooting of lights at the diamond); and why or why not?

Definitely, the animations and data change when the tilt axis changes. What’s more, remember these are virtual models with perfect optical symmetry. AGSL is just scratching the surface. They are in the process of increasing the speed of the tools and the granularity of the tilt studies. With regard to animations it will be useful to show the tilts along a particular axis or along other patterns like a figure-8, as Sergey has programmed into DC. I think it will be interesting to see what they come up with to show several tilts at once. This is going to be a huge job and data compilation will be massive. Logically there will come a point where the data doesn’t shift much with the addition of additional tilts. A sweet spot between speed and accuracy will need to be decided-on; something the lab has done a good job with before in my opinion.

That’s another important distinction between this and other metrics: Tilt is critical to an evaluation of scintillation. Moving lights inside a box is different from tilting the stone. Stones can differ in several different ways when tilted. One critical difference that has a huge impact on appearance is the size of the virtual facets. The “cracked glass” scintillation that you see on the side of an oval looks a lot different than the large bold virtual facets observed in the bow tie areas. The distribution of small, medium, and large virtual facets across the crown also has a huge impact. For example you don’t see broad flashes of fire in stones that lack broad virtual facets. The AGSL scint maps which partition the crown according to scint event size gives the assessor this kind of critical information and insight.

By contrast, looking at a collection of five images only tells you what the stone looks like with the light in five different positions. You can’t create meaningful potential maps with such a limited lighting condition. Also, the photos give you no information on what happens with tilt: Usually when people are observing scintillation it’s the diamond that is in-motion, not the lights in the room.

It’s important to reiterate that, like the fire potential maps, the scint maps are abstractions and not meant to be realistic depictions of scintillation. They have to be interpreted properly in the overall sense of potential to be understood. Remember, this is not a grading metric yet (not even close) but when one is presented it will be built on non-variable, repeatable research.

 

[JohnQuixote]

Strm asked about fire in the other thread and I addressed it above to a degree. That metric is also light source independent, which is possibly the only equitable way for this, and scint, to be quantified unless you plan to live in one room for the rest of your life. Wink Jones has a very good way of explaining the fire maps and the way distance and the human eye factor into what you see in a given scenario - all reinforcing the need for independence.

Date: 6/9/2007 3:00:47 PM
Author: strmrdr

One thing Id like to see addressed in both the fire and scint metrics is scatter and facet junctions.
Observation has lead me to feel that they are the key too both.
Where is the greatest amount of fire returned in a RB diamond?
Study a diamond in multiple lighting conditions and report back.
(pay attention to facet junction locations in relation to the areas of greatest fire)

Jason Quick and Marty Haske both commented along those lines with regard to the benefits of optical symmetry in some diamonds and asymmetry in others. Marty has long maintained that if you get a beam of light in and out of a diamond faster the fresnels don’t mix, so you get purer spectral colors. That’s Diamond 901, since right now AGSL is only separating events by size and frequency, not color.

If I missed any comments that should carryover from the other thread please bring them up. Thanks for the opportunity to discuss.

 

[JohnQuixote]

Here’s an example to further demonstrate the need for light source independence:

Attached is a test for light return. Check the scores. You may chuckle when you realize there is no difference in the images. In fact, all five are of the same stone. It was done to prove a point: The same image was simply rotated on axis 5 degrees in each progression. Intuitively one would assume the readings would be identical with no deviation (which should be the case), especially since this image was given a face-up analysis only. Considering that, there should have been no deviation. Now project this forward and you realize the use of a changing lighting environment on even a static subject will logically reveal more dramatic deviation; results that are NOT repeatable unless you truncate to 10 (not 00.10 but 10.00). This LR test illustrates the variables possible when image analysis or pixel counting are used. The only way to develop a metric for this is to allow for a range of non-repeatability in the result and confine that non-repeatable result to one (or several) lighting conditions at fixed ranges. Unfortunately our world has a near-infinite number of panoramas of illumination, so the results are both non-repeatable and limited in what they can tell us.

Per the above post, AGSL is working towards quantification based on results that are not variable and are repeatable. Comparing their current studies to existing “light box” technologies is like comparing an analysis of tens of thousands of individual rays (in the neighborhood of 60k) at any orientation, subtending to any angle - to counting colored pixels on a face-up image.

AGSL, Dr. Sasian, Sergey and Marty are far ahead when it comes to this area of study.

All of this is not intended to disparage any system: These are the best answers I can provide to the questions posed - there are other perspectives and opinions which should be voiced... Researchers in all fields are to be commended because everyone contributes to our knowledge base. Still, technological advancements in many disciplines can make what we are doing today obsolete next week. You never know, and those of us in the trade are humbled by the efforts of all the researchers out there.

 

[strmrdr]

Some deep questions:
Whats a realistic number of light rays to model?
For any given lighting environment how many are hitting the stone?
Are rays the right way to quantify light?

 

[whatmeworry]

Has AGSL tested their metric against consumer preference? For example, someone may prefer a diamond that shimmers with very little hand movement as opposed to big but infrequent sparkles.

 

[Paul-Antwerp]

Date: 6/13/2007 3:53:43 AM
Author: whatmeworry
Has AGSL tested their metric against consumer preference? For example, someone may prefer a diamond that shimmers with very little hand movement as opposed to big but infrequent sparkles.

This metric is not a grading metric as such, with anyone deciding which is best. At least, not yet.

Taste is a factor in this, and the fact that this is only the beginning of scintillation-research is equally important. Intuitively, the feeling now is that this metric will not lead directly to a grade-evaluation in the sense of this is best. Taste is too important a factor in this.

However, parts of this research might be incorporated in the light performance grade, if for instance this proves that optical symmetry is beneficial (or detrimental) to potential scintillation.

Live long,

 

[Paul-Antwerp]

Date: 6/13/2007 2:29:53 AM
Author: strmrdr
Some deep questions:
Whats a realistic number of light rays to model?
For any given lighting environment how many are hitting the stone?
Are rays the right way to quantify light?

AGS currently models by starting with 40,000 potential starting light rays. This is probably overkill, and when this leaves the area of fundamental research, and it becomes of practical use in the lab, I suppose that the lab will run less rays on the actual virtual models of a stone. This however is a matter of putting fundamental research into practice, while maintaining a sufficiently high comfort level.

I do not understand your second question.

If rays are the right way to quantify light, is a valid question. Sergey has rightly pointed out before that light entering a diamond is a beam, and not a ray. Let us now take it that working with a very high number of rays is a simplification that renders the computation bearable. Even with the limited output which we have seen now, some points are proven, which we already observed in real life, and which we knew intuitively. For instance, the nice division of small, medium-size and large scintillation-events in a symmetrically-cut Tolkowsky, and the difference in scintillation-events in 2-, 3- and 4-chevron princess-cuts.

By the way, thank you to John, for summarizing the information here, and for trying to clarify it.

Live long,

 

[strmrdr]

Paul,
rewording the second question: how many rays does it take to realistically model the real world performance of a diamond for any given lighting situation.
My gut feeling on it is that fire and scint are way more lighting and environment dependant than raw light return.
More info on the specific lighting and environment they are modeling would be helpful.

 

[Paul-Antwerp]

Date: 6/13/2007 4:22:29 AM
Author: strmrdr

Paul,
rewording the second question: how many rays does it take to realistically model the real world performance of a diamond for any given lighting situation.
My gut feeling on it is that fire and scint are way more lighting and environment dependant than raw light return.
More info on the specific lighting and environment they are modeling would be helpful.

Hey storm,

I think that the answer to your question on how many rays it realistically takes to model is in my previous answer. Right now, in their fundamental research, AGS is modeling 40,000 light rays. Which number of rays gives a sufficiently high comfort level probably still needs to be determined. My guess is that the lab will not run the full 40,000 rays on every stone in future, but a lower number which gives sufficient information.

You are in a sense correct that fire and scintillation are dependant upon lighting environment. But so is brightness or brilliance. AGS''s studies are based upon lighting-independence, thus examining the potential to show brightness, fire or scintillation, but not examining the actual observable brightness, fire or scintillation. This is also true, even for the simple ASET-scope, which shows you potential.

After this research of the potential light return, one can study various possible lighting environments and compare to actual observations. AGS has briefly shown us some studies on a round brilliant, calculated in a bright-sunlight-situation, showing that the probability of observing a scintillation-event in bright sunlight is very low.

Does this kind of answer your question?

Live long,

 

[strmrdr]

Thanks Paul,
It did clarify what they are doing.
Not enough info yet to get a good idea if it is the right way.
There is an old saying:
When you have a great hammer every problem looks like a nail.
What would be ideal would be for another group to verify the research in other ways.

Not a lot of visible scint. in bright sunlight makes sense in a lot of ways.

 

[oldminer]

The three dimensional graphs and the concepts are very intriguing. What Strmrdr has said about having a wonderful hammer making all problems look like nails may be appropriate. If the AGSL or any other organization can sell the idea to knowledgeable scientists that this is how the problem of providing a measure of scintillation is to be made, I''d be surprised. There are so many variables that one must choose from nearly an infinite set to "get it right". Even then, I doubt this will be more than sort of an impressive show for marketing. We do love the smoke and mirrors of diamond grading and this is definitely on the subject of smoke and mirrors itself. It is a nice marketing concept, but does it deserve more credence? I have serious doubts.

It is easier to grade the Light Behavior of diamonds with a limited set of variables which give excellent correspondence to beauty while leaving the more minute details to be appreciated by the individual human eye of each purchaser. Scintillation and fire are components present in EVERY well cut diamond and are definitely lacking in poorly cut diamonds. One can define a well cut diamond without resorting to the complexity of calculating potential scintillation or the amount of colored light pixels returned to the eye based on varying the angles of light entering the diamond. This higher complexity of calculation leads us down the path of ERROR creation. You do not need to have any of this to separate a finely cut diamond from a less well cut diamond. Now, that''s my opinion, but it is an opinion held by several others who have pretty high degrees of education. I have a lot of interest in the subject and 40 years of looking at diamonds while making judgments of their attributes.

If one finds a woman with a beautiful face, the presence of a small mole over her upper lip has different consequences for different viewers. Some definitely think her face is highlighted by this little point of special interest and others wonder why she does not have it surgically removed. Many don''t actually notice the mole at all, or don''t consider it a plus or a minus in her appearance. All this work and effort to define characteristics which do not define the character or beauty of a diamond except in a subjective way are "smoke and mirrors". Cindy Crawford likes her mole in the way it helps define her individuality, I suppose.

Think about the importance of characterisitics which are mainstays of judging the cut quality of diamonds and secondary characterisitcs which always come along for the ride with well cut diamonds. This course of action is emphasizing the measurement of secondary characteristics inherent in well cut stones and should not be required for GRADING them. Diamonds are always going to be a beauty contest tempered by affordability. Very few consumers want diamonds by the numbers, calculated for performance by computers and sold to them in a darkened room where thy must rely upon numbers and not their eyes. Let''s trust the value of visual decsion making to some reasonable extent.

 

[Paul-Antwerp]

Dave,

You are advocating the status-quo on the basis of labeling new research as ''smoke and mirrors''. The whole reasoning that you establish in your post then comes down to ''smoke and mirrors'' itself.

Frankly, this is the first time that I see a serious attempt at quantifying and trying to understand what scintillation is and does. This will probably lead to important insights into the effect of the size of virtual facets, and of the effect of symmetrical patterning.

In this, you have to make a distinction between fundamental research (understanding what is going on) and grading (rendering the fundamental research practical), and understand that fundamental research with virtual possibilities has already lead to incredible results in the cutting of extremely fine princess-cuts. Something that had been impossible if one had sticked to studying existing stones, and trying to deduct some grading-rules based upon this observation.

From what I have seen, this whole research on scintillation is only taking its first steps, but in its first results, I already foresee proof of a lot of aspects of cutting, which we know from experience and intuitively, and which might finally get quantified confirmation. As a cutter, this research is perfectly logical to me. If you say that "there are so many variables in scintillation that one must choose from nearly an infinite set to get it right", you probably have a point, but we cutters apparently seem to be able to choose correctly from that infinite set (if we want to), so why should researchers not be able to do this.

If you wish to dismiss this research, you are free to do so. I simply beg to fully disagree with you on this.

Live long,

 

[Paul-Antwerp]

Date: 6/13/2007 6:47:54 AM
Author: strmrdr
Thanks Paul,
It did clarify what they are doing.
Not enough info yet to get a good idea if it is the right way.
There is an old saying:
When you have a great hammer every problem looks like a nail.
What would be ideal would be for another group to verify the research in other ways.

Not a lot of visible scint. in bright sunlight makes sense in a lot of ways.

If that confirmation-group is a community of cutters, that have cut stones to specific standards in the past, of which certain characteristics are now confirmed by the first results of the new AGS-research, is that the possible verification that you are looking for?

Live long,

 

[oldminer]

Paul: As always, I respect your knowledge and appreciate the good advice you often give. I definitely intend to keep an open mind. Instead of just dismissing this new study, I will give it the benefit of trial and time in the market as suggested. To me, at this early stage, it does look more like terrifically interesting marketing, but maybe there is a future for it. I promise to give it a chance as it changes, improves and gets more study.

I would love to have a series of various princess cuts and/or rounds to run on a VeriGem and would spend the money to make it happen. We could then determine what correlation this device has to what is being done elsewhere. I think controlled comparisons, for the sake of knoweldge, not market share, would be good for all concerned.

I do have reservations about endlessly increasing the number of parameters that must be defined to deterime a Cut Grade. At some point, no one will be able to understand the lab reports.

 

[Garry H (Cut Nut)]

Great

resource John

Date: 6/12/2007 9:33:49 PM
Author: JohnQuixote

Jason Quick and Marty Haske both commented along those lines with regard to the benefits of optical symmetry in some diamonds and asymmetry in others. Marty has long maintained that if you get a beam of light in and out of a diamond faster the fresnels don’t mix, so you get purer spectral colors. That’s Diamond 901, since right now AGSL is only separating events by size and frequency, not color.

Marty has long held that view, and I have yet to have good answers from him on several questions.

The only time I ever saw fresnel type mixing of colours is in strongly birefringent gems like faceted calcite, and in Marty''s photo''s which I do not believe could be experianced by a human - especially one with 2 eyes.

In addition, Marty''s thousands of pin point lights that create this PHOTOGRAPHIC effect effectively model presumably paralel rays of light, where as light in the real world is always convergine and diverging from every light source because lights have a finite size (i.e. they are beams). So there for the idea of facet junctions and imaginary rays are just that - imaginary, even though it suits our purpose to think that way - it does not explain the real world.

 

[JohnQuixote]

Date: 6/13/2007 2:29:53 AM
Author: strmrdr

Some deep questions:
Whats a realistic number of light rays to model?
For any given lighting environment how many are hitting the stone?
Are rays the right way to quantify light?

Throw those on the pile with...

- Will we need more than one distance judgment (along the same lines as using both ASET 30 and 40)?
- Can/should we account for stereoscopic vision?
- Tilt-axis questions from above.

Paul''s answers are in-line with my understanding - which is not surprising since we were present for the same information and discussion. I do think brightness is dependent on environment and, while the visible influence of a given environment may not be as dramatic on brightness as it is with dispersion and scintillation, the premise upon which reflectors are based (to show brightness potential) is a good comparison for the premise on which this metric is based (to show scint potential).

 

[strmrdr]

Date: 6/13/2007 8:46:29 AM
Author: Paul-Antwerp

Date: 6/13/2007 6:47:54 AM
Author: strmrdr
Thanks Paul,
It did clarify what they are doing.
Not enough info yet to get a good idea if it is the right way.
There is an old saying:
When you have a great hammer every problem looks like a nail.
What would be ideal would be for another group to verify the research in other ways.

Not a lot of visible scint. in bright sunlight makes sense in a lot of ways.

If that confirmation-group is a community of cutters, that have cut stones to specific standards in the past, of which certain characteristics are now confirmed by the first results of the new AGS-research, is that the possible verification that you are looking for?

Live long,

That''s a good first step towards a proof of concept.
Does it make sense to those skilled in the art?
Id consider that a soft proof.
An important one but still a soft proof.

 

[strmrdr]

Date: 6/13/2007 1:12:15 PM
Author: JohnQuixote

Date: 6/13/2007 2:29:53 AM
Author: strmrdr

Some deep questions:
Whats a realistic number of light rays to model?
For any given lighting environment how many are hitting the stone?
Are rays the right way to quantify light?

Throw those on the pile with...

- Will we need more than one distance judgment (along the same lines as using both ASET 30 and 40)?
- Can/should we account for stereoscopic vision?
- Tilt-axis questions from above.

Paul''s answers are in-line with my understanding - which is not surprising since we were present for the same information and discussion. I do think brightness is dependent on environment and, while the visible influence of a given environment may not be as dramatic on brightness as it is with dispersion and scintillation, the premise upon which reflectors are based (to show brightness potential) is a good comparison for the premise on which this metric is based (to show scint potential).

http://en.wikipedia.org/wiki/Complexity_classes_P_and_NP

light return is a P problem where scint may well be a NP problem.
That AGS is running into computing power issues is a pointer in that direction.
Reducing a NP problem to accurately solve it in P time is the holy grail of computing.

 

[JohnQuixote]

Date: 6/13/2007 8:10:21 AM
Author: oldminer

The three dimensional graphs and the concepts are very intriguing. What Strmrdr has said about having a wonderful hammer making all problems look like nails may be appropriate. If the AGSL or any other organization can sell the idea to knowledgeable scientists that this is how the problem of providing a measure of scintillation is to be made, I'd be surprised.

Hey Dave, the 3D graphic was an approach that was shown NOT to work. If you thought that was part of this metric I apologize for not being more clear. It demonstrates why AGSL put aside fixed environments in favor of independence.

Serg introduced us to ETAS in 2004 and the AGSL approach proceeds from the same premise (stated back at the Moscow cut conference) that fixed environments cannot provide relevant scintillation measures. I regard Serg, Marty and Dr. Sasian as knowledgeable scientists. While they may not agree on every aspect it's nice to see ideas that are walking a similar path. That doesn't mean they are the only paths: Every metric has an Achilles heel...some were just more thoroughly-soaked in the river Styx than others.

 

[JohnQuixote]

The last post got me thinking, so I went and found the quote:

"We are unaware of current devices that can analyze a diamond through a range of tilting, or use many small distant light sources to correctly estimate scintillation." - Sergey, 2004

Nice to see where we've been and where we are trying to go. It will be interesting to look back at this thread in several more years.

 

[Regular Guy]

Date: 6/13/2007 1:12:15 PM
Author: JohnQuixote

- Can/should we account for stereoscopic vision?

This may not be necessary, in consideration of the universal pirate solution....

 

[Paul-Antwerp]

Date: 6/13/2007 1:21:36 PM
Author: strmrdr

Date: 6/13/2007 8:46:29 AM
Author: Paul-Antwerp

Date: 6/13/2007 6:47:54 AM
Author: strmrdr
Thanks Paul,
It did clarify what they are doing.
Not enough info yet to get a good idea if it is the right way.
There is an old saying:
When you have a great hammer every problem looks like a nail.
What would be ideal would be for another group to verify the research in other ways.

Not a lot of visible scint. in bright sunlight makes sense in a lot of ways.

If that confirmation-group is a community of cutters, that have cut stones to specific standards in the past, of which certain characteristics are now confirmed by the first results of the new AGS-research, is that the possible verification that you are looking for?

Live long,

That''s a good first step towards a proof of concept.
Does it make sense to those skilled in the art?
Id consider that a soft proof.
An important one but still a soft proof.

At least, I have the sincere impression that what I have learned from observing stones and from listening to observations of consumers is being confirmed by the first results of this AGS-research. This leaves me very happy and satisfied.

What is more, thinking about the possibility of finally cracking the answer to pattern, symmetry and scintillation as such, which I consider way more important than brightness or fire alone, I am truly excited about this research.

Live long,

 

[strmrdr]

Date: 6/14/2007 4:59:48 AM
Author: Paul-Antwerp

At least, I have the sincere impression that what I have learned from observing stones and from listening to observations of consumers is being confirmed by the first results of this AGS-research. This leaves me very happy and satisfied.

What is more, thinking about the possibility of finally cracking the answer to pattern, symmetry and scintillation as such, which I consider way more important than brightness or fire alone, I am truly excited about this research.

Live long,

kewl
that is good news.

 

[WinkHPD]

Date: 6/12/2007 9:31:08 PM
Author: JohnQuixote
Re: Scintillation...



Knowing the answers to these questions gives you expectations of what you will likely see in the stone. Considering that the number of the world''s lighting environments are closer to infinite than not, decoupling the lighting environment from the metric (as much as possible) seems the way to go. Fortunately, the information now possible by ray tracing the stone allows these sorts of probabilities to be computed, although it’s fried at least one AGSL guru’s computer.

Well sure, he took his 2.5ghz and overclocked it to 3ghz and then decided to see what would happen at 3+ ghz and it ran really fast for a few seconds while he watched the temp rise and before he could shut it down it went into orbit and burned on reentry. Knowing this particular guru, if it did not burn at 3+ghz, it surely would have at 4... LOL and you thought hot rodders were compulsive speed freaks!

Good news is that he was back up and running in only two days...

Wink

P.S. Wonder how far he has overclocked his new mother board???

 

[Skippy123]

Cool! I am visual so this was helpful! Thanks Mr. John

 

[WinkHPD]

Date: 6/13/2007 1:12:15 PM
Author: JohnQuixote

Throw those on the pile with...

- Will we need more than one distance judgment (along the same lines as using both ASET 30 and 40)?
-

I am coming late to the conversation, so this may already have been addressed, if so then just ignore this post...

I think that while it is possible to affect the ASET 30 and 40 with distance, it is originally and probably still intended to do more with head size than distance from the stone. You and I remain more aware of the distance factor as when we try to show stones via the internet cameras that we have it is easy to get 40, 50 or even 60 degrees of obscuration if we do a close up of a stone.

That having been said I believe that I remember Peter Yantzer saying that they were showing these at xyz distance and they had not yet decided if that was the right distance or not. As you have so well said, this is incredible research at its infancy and many changes will show up during the next few years while it is advanced.

Wink

 

[whatmeworry]

Here''s a question sparked by another thread. It''s been opined on this board that round brilliants are more sparkly than say princess cuts or emerald cuts. Has the AGSL scintillation research shown any insights into this?