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Upper Halves - Counter Point

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strmrdr

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First thank you Bill Bray for the article.


Couple points:

No link to info on the:
"W.R.Bray’s Cut Scoring System for Modern Brilliant Cut Diamonds (patent pending, aka BrayScore®)"

....
I found this portion very interesting in concept but less than informative.

"As a side note, measuring the crown height percentage at these points is questionable and could explain inconsistencies of the original AGS Cut Grade System where sometimes a stone with a lower cut grade actually looked better than one with a higher cut grade. Such inconsistence sometimes can be explained by comparing data generated scores produced by the W.R.Bray’s Cut Scoring System for Modern Brilliant Cut Diamonds (patent pending, aka BrayScore®) with AGS cut grades. "

.........
Overall I think I need more info to see where he is coming from vs. AGS and more info on his cut system.
Actualy I should say Id love more information because he is saying a few things that other experts have said here over the years without an explaination. :}
 

pricescope

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Date: 3/25/2005 4
6.gif
8:24 PM
Author: strmrdr

No link to info on the:
''W.R.Bray’s Cut Scoring System for Modern Brilliant Cut Diamonds (patent pending, aka BrayScore®)''
....

http://www.brayscore.com/index2.cfm?Home

http://www.brayscore.com/who.cfm?Who
 

strmrdr

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Garry H (Cut Nut)

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Bill thanks for your article.

I think one thing not explained in Peter's AGS article that was not made clear was that girdle thickness is measured in US labs at the valley or thin part.
Bill you made this comment "Girdle thickness can only be increased by adding more girdle (read reducing the diameter of the stone) either by bruting or faceting or polishing."

What Peter is showing is that the gordle thickness can indeed be made thicker and the spread reduced, yet the stone can still recieve a favourable Lab Report by GIA and the old AGS system - because they measure girdle at the valleys.

AGS will allow AGS 0 grades for this type of indexing (painting and digging) up to a much thicker 5% thickness at the mains (the equivalent of 3.3% at the valley) because they want to allow diamond manufacturers more flexibility to "sculpt" with a free hand. The symmetry measure you have applied in the Bray Score System could need adjusting because it seems that creative cutters have found ways to apply these approaches for the overall good of the diamond (not just to cheat on weight and get better grades than the diamond deserves)
 

He Scores

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Hi Gary, everyone.

First off, let me say that it is not me versus the AGS. I have a lot of respect for the AGS and in particular Peter Yanzer. The AGS built their stature as a grading lab because they attempted to quantify cut when no other lab did. I was only refuting some of the methodology that was used in the article, and not the author or who he works for in general. In the introduction of the section Indexing and Weight Retention it is stated "the only difference is the index of the upper halves and the resultant change in angle of the upper halves". That being the case then, I stand by my correction that the girdle thickness under the mains cannot be made greater by the cutting of the upper halves and thusly the weight retention in that section is unrealistic.

With regard to my standard vs the GIA and AGS standards, BrayScore takes into account the girdle thickness under the mains, under the "scoop" in the halves and under the ribline of the halves. Each individual place has specific relavence to a cutter''s work. When I made the comment about the discrepancy in the old AGS cut grade, where they measured the girdle was what made for the discrepancy, IMHO.

BrayScore accepts a 5% thick girdle. It just deducts more points for it than a 2.5 % girdle. All things consider equal (which is a broad leap of faith) this would represent less than a 10% difference in score....possibly still allowing a 0 cut grade on the AGS scale. or still allowing the stone to be one of the so-called "premium" cuts (HOF, Super Ideal, Eightstar, etc.) With all things equal, a diamond with the thicker girdle will have a smaller diameter. If one had to choose between the two, who wouldn''t take the larger looking stone? Also, in my tests done with people examining stones that have been scored, trade people have a hard time of diffentiating which stone is better when there is a .6% difference of score. This is roughly the same differing of opinions if you were grading a stone a VVS1 or a VVS2.

Also, I sense I know where the GIA and AGS are headed by "allowing" manufacturers leeway with parameters that benefit the cutters and ostensibly the performance of the stone. But everyone should know that there is the possibility of "optical symetry" without "physical symetry". Also the "performance" of a diamond depends on a about a half dozen factors other than cut. BrayScore only evaluates the workmanship of the cutter. You can have a black opaque diamond with a BrayScore of 950 out of 1000, but you can''t have a black Hearts and Arrow diamond. As an analogy, if people bought Rolex''s just for their looks, we''d all be wearing knockoffs. People pay the premium price because of what they can''t see, the 250 miracles of engineering inside that all add up to some chronograph standard.
 

oldminer

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Seems to me, biased as I am, that we could possibly argue the finer points of diamond craftmanship until the last retail consumer flees from boredom or exhaustion. Admittedly, judging a diamond''s "potential" for light performance by finely measuring as many tiny aspects of the cut as humanly possible is the way GIA and AGS have gone, for now, so it seems. This may indeed prove useful for developing super cuts, but it seems a terrible way to measure the ACTUAL peformance of existing diamonds.

We know there are many tricky ways to cheat the systems that exist in order to get grades that we want, even if a bit undeserved. We know that the existing systems that measure cut by parameter can be defeated because we have seen examples to great grades attached to not so great diamonds. Our endless analysis of this has lead to some huge and highly informative threads, but is this the way to move into the future?

If you had a comlex geometric object that needed weighing and knew its specific gravity, would you calculate its weight with formulas or would you place it on a nearby scale? Would a direct measurement not be preferable? I can''t think of when obtaining the weight of that object not be better done on a scale than by calculation. The same is going to prove true with diamonds. The big labs are spending millions to make predictive systems that measure nearly every possible parameter and have yet to admit the degree of error that will result. They really don''t even know, I''d bet. This complex programming will be quite beneficial to cutters who will learn how to first use and then possibly to abuse the system. But measuring DIRECTLY is the right methodology.

As I have been told since 1986, when I first created the beginnings of the AGA Cut Class system, fine parameters do not always make the stone the best. I find them quite useful as screening tools, but I agree the actual look of the stone, an actual, DIRECT measurement with you own eyes, is the final proof of quality of cut.

I think Bill Bray and I agree on nearly every point of craftsmanship in diamonds. One must look at a diamond to know how brilliant it actually is and not assume by calculations that it is not cloudy, or pitch black opaque. Calculating brilliancy is a foolish way to grade and ACTUAL diamond. It is a super way to direct a cutting staff in the production of diamonds, but is not the way major labs should "grade" individual diamonds.

As I first said, I am biased. Others may now defend alternative positions. I would love to hear a valid defense of "calculating" that which could otherwise be directly, repeatably and accurately measured.
 

Serg

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re:This may indeed prove useful for developing super cuts, but it seems a terrible way to measure the ACTUAL peformance of existing diamonds.
re:I would love to hear a valid defense of "calculating" that which could otherwise be directly, repeatably and accurately measured.
It is very strange to use "calculating" method for developing new super cuts only.
If such method is correct( and enough) for developing new super cuts what is reason do not use this method for grade performance of existing diamonds?
 

oldminer

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"If such method is correct( and enough) for developing new super cuts what is reason do not use this method for grade performance of existing diamonds? "
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

I think the reasons for not "calculating" are plainly clear. Calculating does not tell you the degree of opacity of the stone. This could be slight, or total, but a calculation based on physical measurements of facets and angles would not measure this feature. Would you say that this is not a good reason? Another argument against "calculating" versus direct measurement, is the undending arguments and requirements of how much measuring is sufficient to get correcly predicted results. I don''t know that everyone is on the same line in that regard and it has been years in development. For those who rely on old Ogi or Sarin technology, no amount of measuring will suffice due simply to machine error. For folks who choose to rely on Helium''s exotic accuracy, just how much needs to be measured and with what degree of precision to make educated estimates of light behavior? If Helium measured "LIGHT", it would not need to make so many other difficult, minute and critical physical measures.

If I built a scale that weighed objects by first measuring their "exact" volume and then used their specific gravity in order to predict weight and put it up against another manufacturer who just offered a modern scale that gave an exact weight, which one would a logical individual purchase for daily weighing of materials? Would you opt for the more complex approach or the simple approach, if they both work equally as well? Would you still opt for the more complex approach if it was slower or a tiny bit less reliable due to machine error? Could you even suggest that the simpler model would EVER be less accurate than the complex method?

Both methods of diamond light behavior measurement will work most of the time, but there are inherent flaws in thinking that a calculated light measurement will be a superior method for daily lab use.
As I said before, the calculation method will be more suitable for developing cuts to be produced in volume as brands or as high performance stones. The direct measure method is what I would see as the proper course for laboratory use in grading. Every diamond is an individual and not all will perform as predicted.....On this, I believe I am on safe ground.
 

Garry H (Cut Nut)

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Date: 3/26/2005 2:48:25 PM
Author: oldminer

As I said before, the calculation method will be more suitable for developing cuts to be produced in volume as brands or as high performance stones.

Dave, this is Sergey''s point. We need a method to design the most favourable yielding, desirable looking diamond from each piece of rough. This can most effectively be accomplished with a calculating software. By making it possible for software to predict the appeal of a new never before seen diamaond, manufacturers and the market will be released from the current ''commodity market'' in the same way that painting and sculpture is raised above commodity marketing.

The direct measure method is what I would see as the proper course for laboratory use in grading. Every diamond is an individual and not all will perform as predicted.....On this, I believe I am on safe ground. A by product of Sergey''s approach will be the validation of all cut grading systems, since what we know so far is that direct performance measurement techniques do not all give the same high or low scores for the same diamonds.
BTW can you tell us what the Imagem results are for the same stones on the brilliancescope and ISee2?
 

oldminer

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If I had a willing source to "SHARE" stones graded with Gemex or ISee2 and then with ImaGem, I would be very willing to participate with a secure comparison. Maybe we can make it happen.
 

mdx

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Date: 3/26/2005 2:48:25 PM
Author: oldminer
''If such method is correct( and enough) for developing new super cuts what is reason do not use this method for grade performance of existing diamonds? ''
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

I think the reasons for not ''calculating'' are plainly clear. Calculating does not tell you the degree of opacity of the stone. This could be slight, or total, but a calculation based on physical measurements of facets and angles would not measure this feature. Would you say that this is not a good reason? Another argument against ''calculating'' versus direct measurement, is the undending arguments and requirements of how much measuring is sufficient to get correcly predicted results. I don''t know that everyone is on the same line in that regard and it has been years in development. For those who rely on old Ogi or Sarin technology, no amount of measuring will suffice due simply to machine error. For folks who choose to rely on Helium''s exotic accuracy, just how much needs to be measured and with what degree of precision to make educated estimates of light behavior? If Helium measured ''LIGHT'', it would not need to make so many other difficult, minute and critical physical measures.

If I built a scale that weighed objects by first measuring their ''exact'' volume and then used their specific gravity in order to predict weight and put it up against another manufacturer who just offered a modern scale that gave an exact weight, which one would a logical individual purchase for daily weighing of materials? Would you opt for the more complex approach or the simple approach, if they both work equally as well? Would you still opt for the more complex approach if it was slower or a tiny bit less reliable due to machine error? Could you even suggest that the simpler model would EVER be less accurate than the complex method?

Both methods of diamond light behavior measurement will work most of the time, but there are inherent flaws in thinking that a calculated light measurement will be a superior method for daily lab use.
As I said before, the calculation method will be more suitable for developing cuts to be produced in volume as brands or as high performance stones. The direct measure method is what I would see as the proper course for laboratory use in grading. Every diamond is an individual and not all will perform as predicted.....On this, I believe I am on safe ground.
Hi Dave
How can the industry be expected to except the concept of direct measurement, interpreted by software when the manufacturers of these devises are unwilling to submit the technology to peer revenue?
If the manufacturers can tell us ordinary diamond professionals the principles behind what direct measurement actually measures, how the software interprets the measurement and why it’s relevant then perhaps we could be persuaded.

Based on the information currently available to the industry I would have to conclude that 3d scanning and calculating software is far more accurate than direct measurement.

Johan

 

strmrdr

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Date: 3/26/2005 6:21:54 PM
Author: oldminer
If I had a willing source to ''SHARE'' stones graded with Gemex or ISee2 and then with ImaGem, I would be very willing to participate with a secure comparison. Maybe we can make it happen.

You allready did when Jon was there at your place.
He should be able to provide isee2 and b-scope scores on the diamonds he ran.
 

strmrdr

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Date: 3/26/2005 6:41
6.gif
0 PM
Author: mdx
Date: 3/26/2005 2:48:25 PM

How can the industry be expected to except the concept of direct measurement, interpreted by software when the manufacturers of these devises are unwilling to submit the technology to peer revenue?

If the manufacturers can tell us ordinary diamond professionals the principles behind what direct measurement actually measures, how the software interprets the measurement and why it’s relevant then perhaps we could be persuaded.


Johan

I agree with mdx big time on the need for open standards and peer review.

I think that both camps have just as many issues and while both are interesting and can be very informative I dont think that any of them are good enough to be used as the only test of a diamond.
When they are available they should be viewed as one part of the puzzle not the whole picture.
 

oldminer

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I have no experience with "peer review", especially with trade secret, patent protected technologies. I leave this up to the folks at ImaGem, Inc to provide the permissions to interested parties and to work out how the process might evolve. I know outsiders have been employed by investors during the creation of this technology and at each stage outside review and approval was given for accuracy of performance. Possibly this constitutes peer review having already been done, but those in the know will have to make up their own minds on that.

I am a user of the technology, not a scientist. We want real working tools to rapidly and accurately analyze actual diamonds in lab grading work. There may be other goals, such as designing theoretical cuts, more suited to predictive devices, but no one has yet to say actual measuring on actual diamonds is an undesireable approach. Those who promote calculating performance are generally biased in that that is the method they are attached to. I have asked questions which highlight my perceptions of weaknesses in their technology for use in lab work and have not gotten a direct response.

We can all be doubters. It is easy to say "prove it". I can run a number of round stones, give repeatable ImaGem results individually for brilliancy, sparkle and intensity, give my own classification word grades for these numbers and cook it into a final result. This takes into account any and all variation in the cut of an individual diamond without making a scientific facet measuring monster out of it.......I like keeping it simple and hope people will take the opportunity to give it a try.
 

valeria101

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Date: 3/26/2005 11:18:42 AM
Author: oldminer

Seems to me, biased as I am, that we could possibly argue the finer points of diamond craftmanship until the last retail consumer flees from boredom or exhaustion...


9.gif
trying to add to this line... and step back a bit from "brilliance" into simple metrics.

34.gif
What kind of harm is done if only light return (or loss relative to the intensity of some controlled source) would be measured ? (= nothing about contrast, scintillation, fire... whatever metrics tuned to human perception and expectations about diamond aestetics).


I am not expecting an intricate reading list for answer, just a strykingly ugly GA example (or just verbal description) that would pass such simple light return test.


 

He Scores

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I have no problem with someone reviewing my patent information. I won''t be hospitible to supply it to people. I will welcome debate. The problem with "peer review" is the same problem with designing new designs...people will copy them. Oh sure...we''re protected by copyright and patent laws, but large institutions can litigate a small guy into the poor house. Even though I had non-disclosure agreements with labs and equipment manufacturers, I can see portions of my methodology being put to use to their good fortune.

Bill


Date: 3/26/2005 11:46:16 PM
Author: strmrdr

Date: 3/26/2005 6:41
6.gif
0 PM
Author: mdx

Date: 3/26/2005 2:48:25 PM

How can the industry be expected to except the concept of direct measurement, interpreted by software when the manufacturers of these devises are unwilling to submit the technology to peer revenue?

If the manufacturers can tell us ordinary diamond professionals the principles behind what direct measurement actually measures, how the software interprets the measurement and why it’s relevant then perhaps we could be persuaded.




Johan

I agree with mdx big time on the need for open standards and peer review.

I think that both camps have just as many issues and while both are interesting and can be very informative I dont think that any of them are good enough to be used as the only test of a diamond.
When they are available they should be viewed as one part of the puzzle not the whole picture.
 

Garry H (Cut Nut)

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I have been suggesting to the good folks at Bscope that they undertake a little peer review. They say they did it all with the boffins before release, but the boffins may not have been the best boffins for the job - only the ones that were available, or were thought to have the relevant skills.
Peer review means publishing how, what, where and why type stuff - and being susceptable to review in the same journals or other journals.

in theory the patent process does this - the patent says to the world - I tell you how to do it - and the govt gives me 17 years monopoly etc. But we all know that today the patent process often does not give enough info away for "those skilled in the field to reproduce the art".
 

He Scores

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Thank you Gary,

I''ll try to put together some articles explaining my scoring process. If anyone has any suggestions or questions email me directly and I''ll try to address them in a public forum. I would like to become part of this ongoing industry debate.


Bill
 
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