AGS introduces cut grading on DQR reports

[adamasgem]

Date: 10/24/2008 5:24:44 PM
Author: strmrdr

Therefore its confidence level is less than half of a 3d system.

Storm, You are entirely correct that the Gold confidence level probably falls much below that of the Platinum, how much I don''t know, everyone''s opinions are purely guesses on that statistic to this point, and maybe it is only 50%, but that would still put GIA''s below that, in my opinion.

And I''m glad to see you talking about CONFIDENCE levels, because that is what it is all about, confidence in the grade assigned. I only hope that the Gold and Platinum analogies are understood by the consumer, and that people have to be educated about the limitations of systems based on averages, besides the fact they are two different systems.

I think there may have been a mistake somehow in using the same terminology, but I don''t think there were obvious choices, maybe HIGH TOP, LOW TOP, HIGH MIDDLE, LOW MIDDLE, HIGH BOTTOM, LOW BOTTOM, but that may not be politically palatable, nor saleable, so Gold and Platinum may have been the logical conclusion.

Maybe if there were no Gold Ideal range, it would solve the terminology problem confusion.

Maybe High EX is the solution. Everyone looks for superlatives.

 

[Serg]

Date: 10/24/2008 12:20:15 PM
Author: adamasgem

Date: 10/23/2008 11:37:46 AM
Author: Serg




reGS is entirely dependent on the actual scanned stone.

Marty,
1)It is very well known
2) it is not issue.


If AGS changed weighed for Tilt during develop ASG Gold.

They should do some changing light metric( weighed Tilt in same way) for AGS Platinum( yes it could be much more computer time costly do it for each scanned model). But Otherwise light metrics for ASG Gold and AGS Platinum are different.

And most probably light metric for ASG Platinum is worse ( less correct) than for ASG Gold
But according AGS Platinum Brand , ASG platinum light metric should Best( most correct at least among all ASG cut grading systems)


I think i have not ''conceptual or a political problem''. But because you defiantly do not like listen about this ASG conceptual problem, you could have some political reason( problems) do it.

Serg.. I think if you read the attached pdf, which are copies of data published 3 years ago and are somewhere in the PS archives, you may realize that you do have a conceptual problem, or else you haven''t read or understood what I have said. What more can I say, I think the data speaks for itself in supporting what I have said, and you certainly haven''t presented anything contrary. The designations refered to those describing the GIA from their article on fire. They are on PS somewhere also.

Those limited runs, represented a hell of a lot of number crunching using a symmetrical model, and Garrys contribution showing how a stone went from light to dark with a small change in tilt supported the theoretical work, so stop trying to start an argument or confuse the issue. Facts are facts.

Marty,
Re: "
I think if you read the attached pdf, which are copies of data published 3 years ago and are somewhere in the PS archives, you may realize that you do have a conceptual problem, or else you haven''t read or understood what I have said. What more can I say, I think the data speaks for itself in supporting what I have said, and you certainly haven''t presented anything contrary.
Those limited runs, represented a hell of a lot of number crunching using a symmetrical model, and Garrys contribution showing how a stone went from light to dark with a small change in tilt supported the theoretical work, so stop trying to start an argument or confuse the issue. Facts are facts. "

You did not show yet ANY fact which has any connection with my statements in this thread
You are speaking
1) How 3d model is important. Why 3d model is better than set of parameters
2) Why tilt is important ..
But
1) it has not any connection with my statements in this thread
2) It is very well known now. Lets remind you what OctoNus had started to use 3d model( scanned and ideal) and tilt much early than ASG . It is not necessary explain me the advantages of Octonus technology

 

[Serg]

Date: 10/18/2008 3:59:38 AM
Author: Regular Guy
Good morning.

In the spirit of being willing to ask a dumb question in the hope of adding a little value at least for myself (actually...having earlier not made the observation I did just make, and having assumed about this yesterday, I became very excited)...I presume in your chart presented here in this post, Serg (but missing the chart as I post it below):

Date: 10/17/2008 3:29:56 AM
Author: Serg
Chart AGS2008&AGSPGSnovember2007

you''re intentionally not posting comparative data for pavilion at the odd degrees...(i.e. for 34.5 crown...a) at 40.8 it shows both ID and 0, but b) at 40.9, it just shows ID).

Here you can find full data now.

AGS GOLD 2008 & AGSPGS 1.1.2 November 2007

and

AGS GOLD 2008 for Table 52% - 65%

Thanks, Mr. Paul S. for reminder

 

[adamasgem]

Date: 10/25/2008 10:17:06 AM
Author: Serg



Marty,

Re: ''
I think if you read the attached pdf, which are copies of data published 3 years ago and are somewhere in the PS archives, you may realize that you do have a conceptual problem, or else you haven''t read or understood what I have said. What more can I say, I think the data speaks for itself in supporting what I have said, and you certainly haven''t presented anything contrary.
Those limited runs, represented a hell of a lot of number crunching using a symmetrical model, and Garrys contribution showing how a stone went from light to dark with a small change in tilt supported the theoretical work, so stop trying to start an argument or confuse the issue. Facts are facts. ''


You did not show yet ANY fact which has any connection with my statements in this thread

You are speaking
1) How 3d model is important. Why 3d model is better than set of parameters
2) Why tilt is important ..

But
1) it has not any connection with my statements in this thread
2) It is very well known now. Lets remind you what OctoNus had started to use 3d model( scanned and ideal) and tilt much early than ASG . It is not necessary explain me the advantages of Octonus technology

Do we have Agenda versus Objectivity?

 

[adamasgem]

ate: 10/25/2008 10:17:06 AM
Author: Serg


Marty,

But
1) it has not any connection with my statements in this thread Wrong
2) It is very well known now. Lets remind you what OctoNus had started to use 3d model( scanned and ideal) and tilt much early than ASG . If you would ask AGS for one, I have been supporting your technology for a long time. Who do you think was partly responsible for your invite to the Orlando conclave, not to mention your initial Las Vegas meeting. It is not necessary explain me the advantages of Octonus technology

Sergey, I think you are getting your panties tied in a knot by confusing the objectives of your cut planning software and grading software, which may be at odds with objective post cutting evaluation.

1) It is common sense that, with todays technology and computer speeds, one cannot do other than a rudimentary, average parameter based, lookup table approach to rough cut optimization.

2) It is common sense that the wider the ultimate "grading" ranges (the liberal GIA concept that all diamonds are equal), the easier task in selling "weight yield optimization". Faster, better cheaper (remind you of NASA disasters) is the cutters goal, more profit, hence, in effect, what seems to be your goal.

3) It is common knowledge that you (since MSU) have had your own averaged parameterized system, based on the early idealized models (HCA example), and that it is difficult in getting it accepted, especially when there is GIA and AGS competition and that it just takes too long to ray trace a stone and properly evaluate it for more than a limited set of conditions. Hence the necessity for averaged parameter models for the global market, and proper evaluation for the small subset (maybe 5%) of those who really care and/or understand.

4) Most consumers (guys buying an engagement ring) just want to get it over with, and truly get what they pay for, and has been advertized to them, out of their limited, already strained, budgets. Most optimizations of this type globally, seem to be more bang for the buck.

5) No one, and I repeat no one, including you, has ever been able to present confidence bounds based on the errors in the results of any parameter based grading system, let alone the same for any complete ray tracing analysis. Cut optimization is still slowly crawling out of the stone age, due to the enormity of the task and the vast amounts of money and time required to do it "right", whenever everyone can agree on what "right" is.

 

[Serg]

Date: 10/27/2008 2:33:40 PM
Author: adamasgem

ate: 10/25/2008 10:17:06 AM
Author: Serg





Marty,




But
1) it has not any connection with my statements in this thread Wrong
2) It is very well known now. Lets remind you what OctoNus had started to use 3d model( scanned and ideal) and tilt much early than ASG . If you would ask AGS for one, I have been supporting your technology for a long time. Who do you think was partly responsible for your invite to the Orlando conclave, not to mention your initial Las Vegas meeting. It is not necessary explain me the advantages of Octonus technology

Sergey, I think you are getting your panties tied in a knot by confusing the objectives of your cut planning software and grading software, which may be at odds with objective post cutting evaluation.

1) It is common sense that, with todays technology and computer speeds, one cannot do other than a rudimentary, average parameter based, lookup table approach to rough cut optimization.

2) It is common sense that the wider the ultimate 'grading' ranges (the liberal GIA concept that all diamonds are equal), the easier task in selling 'weight yield optimization'. Faster, better cheaper (remind you of NASA disasters) is the cutters goal, more profit, hence, in effect, what seems to be your goal.

3) It is common knowledge that you (since MSU) have had your own averaged parameterized system, based on the early idealized models (HCA example), and that it is difficult in getting it accepted, especially when there is GIA and AGS competition and that it just takes too long to ray trace a stone and properly evaluate it for more than a limited set of conditions. Hence the necessity for averaged parameter models for the global market, and proper evaluation for the small subset (maybe 5%) of those who really care and/or understand.

4) Most consumers (guys buying an engagement ring) just want to get it over with, and truly get what they pay for, and has been advertized to them, out of their limited, already strained, budgets. Most optimizations of this type globally, seem to be more bang for the buck.

5) No one, and I repeat no one, including you, has ever been able to present confidence bounds based on the errors in the results of any parameter based grading system, let alone the same for any complete ray tracing analysis. Cut optimization is still slowly crawling out of the stone age, due to the enormity of the task and the vast amounts of money and time required to do it 'right', whenever everyone can agree on what 'right' is.

Marty,

Re: 1) it has not any connection with my statements in this thread . Wrong

Please just write 1-2 my main statements.

Did I write your statements correctly?

Re: I think you are getting your panties tied in a knot by confusing the objectives of your cut planning software and grading software, which may be at odds with objective post cutting evaluation

I do not see any way How ASG gold grading system can create any problems to OctoNus business, specially for planning software .
Please explain what do you mean?

I do not see any problems for OctoNus business at all

Re: It is common knowledge that you (since MSU) have had your own averaged parameterized system, based on the early idealized models (HCA example), and that it is difficult in getting it accepted, especially when there is GIA and AGS competition and that it just takes too long to ray trace a stone and properly evaluate it for more than a limited set of conditions


I ( and All Octonus too) have not any connection with HCA . I ( or OctoNus) Has not any “averaged parameterized system”
What do you mean here?
Do you have Agenda versus Objectivity?

 

[adamasgem]

Date: 10/27/2008 3:22:32 PM
Author: Serg


Marty,

Re: I think you are getting your panties tied in a knot by confusing the objectives of your cut planning software and grading software, which may be at odds with objective post cutting evaluation

I do not see any way How ASG gold grading system can create any problems to OctoNus business, specially for planning software .
Please explain what do you mean?

I do not see any problems for OctoNus business at all

Sergey what I meant was that you seem to be the one attacking an admittedly looser and different sysetm because the "results" don''t click or coincide, a problem that may be largely terminology based and the fact that they are two different systems, both probably constantly evolving by necessity as we learn more.

I don''t know how the AGS GOLD system results conflict with your own cut grading methodologies and optimization, but being different than the PLATINUM certainly can cause consternation.

Actually the AGS Gold should help your optimization.

 

[Serg]

Date: 10/27/2008 3:57:11 PM
Author: adamasgem

Date: 10/27/2008 3:22:32 PM
Author: Serg



Marty,

Re: I think you are getting your panties tied in a knot by confusing the objectives of your cut planning software and grading software, which may be at odds with objective post cutting evaluation

I do not see any way How ASG gold grading system can create any problems to OctoNus business, specially for planning software .
Please explain what do you mean?

I do not see any problems for OctoNus business at all

Sergey what I meant was that you seem to be the one attacking an admittedly looser and different sysetm because the ''results'' don''t click or coincide, a problem that may be largely terminology based and the fact that they are two different systems, both probably constantly evolving by necessity as we learn more.

I don''t know how the AGS GOLD system results conflict with your own cut grading methodologies and optimization, but being different than the PLATINUM certainly can cause consternation.

Actually the AGS Gold should help your optimization.

re:Actually the AGS Gold should help your optimization.

It is not important for our optimization .
early Cutters use PGS charts , Now they will use ASG gold charts.( we do not need even do anything for it)
of course ASG gold Charts are more safe for Cutters

But ASG gold grading system has not change OctoNus planning business.
Sarin , OGi, OctoNus,.. clients will use same data from ASG. Nobody( from scanners companies) could receive advantages .
But AGS gold grading system create problems for ASG Platinum grading systems ( specially if ASG will not introduce ASG Platinum grading system for new Fancy cuts, but will introduce ASG gold grading system for Princess cut)
One reason why ASG gold create problem for ASG Platinum , I tried explain in this thread.
But you do not want listen me. You think what I attack AGS because I see problems for OctoNus business .
( I do not see any problem for Octonus business , I see problem for ASG Platinum system and I am trying show the way to fix this problem)

 

[adamasgem]

Date: 10/27/2008 4:28:29 PM
Author: Serg



re:Actually the AGS Gold should help your optimization.

It is not important for our optimization . So you have your own optimization, that is well and good.
I can imagine that cutters have either acccepted or rejected it, or set their own standards or that it might be purely weight retention. From a rough standpoint it seems offhand that shape and overall depth are probably the major criteria, because then come the angle sets you can make from the preform. Care to enlighten us?????

early Cutters use PGS charts , Now they will use ASG gold charts.( we do not need even do anything for it)
of course ASG gold Charts are more safe for Cutters Yes

But ASG gold grading system has not change OctoNus planning business.
Sarin , OGi, OctoNus,.. clients will use same data from ASG. Nobody( from scanners companies) could receive advantages . OK

But AGS gold grading system create problems for ASG Platinum grading systems ( specially if ASG will not introduce ASG Platinum grading system for new Fancy cuts, but will introduce ASG gold grading system for Princess cut) Sergey, All things in their time, the most popular first, just as you prioritise, apparently so does AGS, all I''ll do is stick my two cents worth in when I see fit.

One reason why ASG gold create problem for ASG Platinum , I tried explain in this thread.

But you do not want listen me. You think what I attack AGS because I see problems for OctoNus business .

Then please accept my apology if I somehow ,isunderstood your intensions.

( I do not see any problem for Octonus business , I see problem for ASG Platinum system and I am trying show the way to fix this problem)
I think there is a use of terminology problem, that needs to be addressed.

 

[strmrdr]

My objections are really very simple and while this discussion has gone well beyond that I think the simple stuff is more than enough to recommend rejecting the new system.

Does the new system call diamonds ideal that the 3d system would not? YES
Is the new system more prone to tricks and cheating than the 3d system? YES
Is 2 different grading systems with the same name for the top grade from the same lab confusing to consumers? YES
Those are facts that can not be disputed.

My opinion: This effort to take advantaged of the good reputation the 3d system has achieved for the industries gain $$$$$$ is wrong and should be rejected.

 

[Serg]

Date: 10/17/2008 3:28:00 AM
Author: Serg

Date: 10/16/2008 1:15:52 AM
Author: Regular Guy

Date: 10/10/2008 1:05:14 PM
Author: Serg

Ira, we have full information.
I need receive permission for publication firstly

Serg,

With JP''s post and link...above and here...I think that with the charts having been made public...having permission becomes moot...not relevant.

I can''t cut & copy the text at their front page, but the claim is that the proportions based system is based on their 3D system....as had been my original assumption and hope.

I read you may have discerned particular crown & pavilion combos otherwise?

Can you explicate now?

Regards,

Yes, Please find comparison chart for AGS PGS November 2007 version and new AGS system
Correlation between PGS AGS0 and ASG ideal is 58% just
I hope this chart has not critical bugs. I had not time check it currefully.

re:Yes, Please find comparison chart for AGS PGS November 2007 version and new AGS system
Correlation between PGS AGS0 and ASG ideal is 58% just

I should add details to this my statement

Yes, Please find comparison chart for AGS PGS ( version 1.1.2 November 2007) version and new AGS system for table 57%
Correlation between PGS( version 1.1.2 November 2007) AGS0 and ASG ideal on this chart is 58% just

Mr. Paul Slegers,

Is it good enough now?


Could anybody check correlation between PGS ( version 1.1.2 November 2007) ASG0 and ASG Ideal charts for all tables?

please find data here

 

[adamasgem]

Date: 10/29/2008 4:38:51 PM
Author: Serg

Could anybody check correlation between PGS ( version 1.1.2 November 2007) ASG0 and ASG Ideal charts for all tables?

please find data here

Sergey, I suppose you have all the data you have published in a excell spread sheet or csv file format.
Forward to me and I''ll take a look.

Peter released GOLD, and I made up from GIA''s Diamond grading course material, a csv for GIA, but I don''t have the PGS in a usable form EVEN THOUGH THE COMPARISON BETWEEN PLATINUM AND GOLD MAY BE SOMEWHAT MEANINGLESS.

I would iike to see the distribution statistics on the correlations between ALL systems.

Peter has already shown that, literally no stone makes a GIA poor, AND the 35%, AS i REMEMBER, of the set that AGS terms POOR are GIA GOODS.

The three systems use different criteria and you would expect some lack of correlation near ridge lines.

 

[Serg]

All PGS chart had been calculated for

“Parameters used in PGS: 3% girdle bezel, 55% Star (45% upper girdle) and 80% lower girdle facet length (81.5% lower facet depth).”

Please repeat our calculation. It is best way to find misprints

 

[Serg]

Below is some “summary” :

NEW ASG grading system DOWNGRADE +_ (40)% AGS PGS 0( or AGS Platinum 0 ) .
( *I checked it for T57% and some other Tables .AGS PGS charts were prepared for 3% girdle bezel, 55% Star and 80% lower girdle facet lengthfor 3% girdle bezel, 55% Star and 80% lower girdle facet length . Only star is on boundary AGS ideal range. Other two parameters are inside. Anybody can check it for same parameters and for other range ASG Gold)

In same time ASG GOLD could very often upgrade ASG platinum for diamonds without ideal 3d symmetry .
There is not problem If New AGS cut grading system is more strict than ASG Platinum
There is not problem If New AGS cut grading system is more soft than ASG Platinum
But because new and old ( with hide value market Brand) cut grading system is SO different ( simply contradictive systems) there is big problem.

How should consumer understand what RBC is best?
Some sellers will use ASG Platinum and say "we use most ASG advanced cut grading system based on real 3D model"
But other sellers will say "We use newest ASG cut grading system what is more strict because I will show you ASG 0 RBC what has can not receive AGS Ideal grade. My Ideal diamonds is BEST. Did you bought ASG0 early ? You need check it, may your stone is not Ideal more "
My suggestion to change ASG Gold or ASG Platinum to increase consistency between with two different systems. ASG Gold should not do downgrade at least ASG0 RBC

Just few more facts:

1) Correlation between GIA and AGS Gold TOP grade charts is 44% ( for Table 57%)
2) Correlation between GIA and AGS PGS TOP grade charts is 46% ( for Table 57%)

Is it much worse than 56% between AGS Gold and AGS PGS TOP grade charts ?

if GIA cut grading is so bad why are Both ASG cut grading systems so fine ???

Either all 3 systems are fine or at least two systems from these three are bad.

What is your choice :
1) GIA has fine cut grading system ?
2) ASG has at least one bad cut grading system ?
3) All 3 systems have similar level of quality and far from perfect systems
Of course there are false, false and statistics
I agree what statistics can not be used here like PROOF,
I use statistic just push you to open mind and release possible problems in near future if AGSL will not change at least one ASG cut grading system now

But in ANYCASE situation when ASG Gold ( parametrical cut grading system ) downgrade a lot of ( may be even more than 50%) AGS PGS 0 Is very bad for reputation AGS Platinum and AGS Brand .

It does not matter what its are different systems .

My main statement is what ASG GOLD downgrade to much ASG 0. this statement correct in any case .
Please listen and discuss firstly main point without any demagogy ( what system are different. Yes system are different who argue it?)

 

[Regular Guy]

To Serg''s second point...I don''t understand so much...44 and 46% seem close to me, and I could understand how these, mirroring each other, use a different metric than GIA.

To your first point, despite the different systems (remember...if gold = ruffles, confusion clarified....or...nevermind...I can concede this point

)...it could be good for some of us to intuit better, Marty, why one diamond, in either system, having one ideal set of proportions, would really be counted differently as to inside or outside a border...and this may need a Zukerman math lesson sidebar to get it. Or not.

Maybe even...we could conceive of some functional meta-analysis...and apply it where it belongs. That is...what proportion of people specifically seeking an AGS certificate read Pricescope? AGS may not have an interest in providing the necessary education of ciphering between gold & platinum. That remains to be seen. But...it does seem that a point of probable important agreement is the relative real goodness of the systems with respect to each other. The rough numbers, Marty was reluctant to confirm, but which Storm stipulated, were these:

Date: 10/20/2008 6:19:49 PM
Author: strmrdr

Date: 10/20/2008 12:49:58 PM
Author: adamasgem

Date: 10/20/2008 12:07:00 PM

Author: strmrdr


Another example is a diamond with certain numbers and 80% lgf% will get plat. ideal but not with 75% lgf%.

Both of those will get ideal under the gold system.


How about the stones that Todd used to call fake ideals what would be cut with a wide range of pavilion angles to average just under the required number on the old AGS system.

AGS is heading back to those days.

Storm, yes, it appears a regression of a sort back to 2D, forced by the economic dominance of the 800# gorrila in the room, but it is still probably better than the generations OLD AGS 2D parameter based system (the original 0-10) because of the research behind it, and yet it appears still much more selective than GIA.

In my opinion if one has no other information other than the cut grade the odds of the potential of getting a nice high performance round that may not be the best of the best but solid worth buying high performance stones with the systems are:
Before tricks and selective cutting.
AGS DQD Ideal - 96% confidence
AGS Gold Ideal 85% confidence
GIA EX - 75% confidence.

After cutting tricks and selective cutting.
AGS DQD Ideal - 95% confidence (there isn''t a lot of room for cheating and its the tightest range)
AGS Gold Ideal - 40% confidence (an awful lot of them will be cut to the steepest deepest allowed)
GIA EX - 20% confidence. (an awful lot of them ARE cut to the steepest deepest allowed)

The AGS DQD Ideal is almost immune to tricks and selective cutting that was why it was an advance.
Tricks and selective cutting can lower the potential for the consumer to get what the grade promised by a huge margin in 2d systems.

Maybe it could be helpful to understand this bigger picture better, anyway.

Regards,

 

[Garry H (Cut Nut)]

Date: 10/31/2008 4:29:15 AM
Author: Serg


Of course there are false, false and statistics

Sergey I think you mean this?

"Lies, damned lies, and statistics" is part of a phrase attributed to Benjamin Disraeli and popularised in the United States by Mark Twain: "There are three kinds of lies: lies, damned lies, and statistics." The statement refers to the persuasive power of numbers, the use of statistics to bolster weak arguments, and the tendency of people to disparage statistics that do not support their positions.
http://en.wikipedia.org/wiki/Statistical_deception

 

[Serg]

Date: 10/31/2008 8:18:42 AM
Author: Garry H (Cut Nut)

Date: 10/31/2008 4:29:15 AM
Author: Serg




Of course there are false, false and statistics

Sergey I think you mean this?

''Lies, damned lies, and statistics'' is part of a phrase attributed to Benjamin Disraeli and popularised in the United States by Mark Twain: ''There are three kinds of lies: lies, damned lies, and statistics.'' The statement refers to the persuasive power of numbers, the use of statistics to bolster weak arguments, and the tendency of people to disparage statistics that do not support their positions.
http://en.wikipedia.org/wiki/Statistical_deception

Thanks Garry,
Good to know original version.

 

[Serg]

re:To Serg''s second point...I don''t understand so much...44 and 46% seem close to me, and I could understand how these, mirroring each other, use a different metric than GIA.

I checked correlation between GIA charts and two type ASG charts( results are 44 and 46%) and between two AGS charts( for Platinum and gold grading system result is 56%) . Stars, LGF , Girdle and Table had been fixed during such comparison

re:AGS may not have an interest in providing the necessary education of ciphering between gold & platinum. That remains to be seen. But...it does seem that a point of probable important agreement is the relative real goodness of the systems with respect to each other.

I hope ASG will publish explanations. It is one of my main two reasons of my publications on PS.

We need try stop building the new Ivory Tower. ( Like GIA did it before) . Several years ago ASGL was more open for discussions and delivery much mpore information to support new cut grading system .
Today AGSL have published standard for new cut grading system without any Link to "Scientific" source such data. they did not publish any methodology How they received such cut grading system.

 

[adamasgem]

Date: 10/29/2008 7:52:34 PM
Author: Serg

All PGS chart had been calculated for

“Parameters used in PGS: 3% girdle bezel, 55% Star (45% upper girdle) and 80% lower girdle facet length (81.5% lower facet depth).”

Please repeat our calculation. It is best way to find misprints

Send me the money and the time and I''d be happy to, otherwise it is a rediculous demand on anyone

 

[michaelgem]

There are some underlying facts, only lightly touched upon, that have been buried by distracting issues such as “confidence levels”, “levels of trust or certainty”. Here is the principal one:

The cutter has to deal with a grading system based upon, not probabilistic confidence levels, but the deterministic presentation of that system in the form of charts like those of GIA, the AGS Gold and those that Sergey''s cut grade task force has generated from the PGS software.

There is no other way I know of that the cutter can visually deal with such a multi-dimensional optimization problem, except to view 2-D slices of the 3-D space (table %, pav angle, crown angle) under the constraints of his chosen fixed girdle %, star length, indexing, and half length.

Perfect symmetry is chosen as the simplest and best case scenario. Optical symmetry is assumed, because both GIA and AGS require high symmetry for a diamond cut to get the highest grade. If the PGS software gave a better grade to a diamond whose symmetry was purposely reduced from perfect, it would be in contradiction to the requirement of ideal symmetry. That in turn would raise the uncomfortable specter of a grading system that rewards with a higher grade, a cut with less craftsmanship than another.

It strains all credibility that, by using charts, someone can be accused of being intentionally misleading, by simply comparing grading systems in this visually meaningful, informative and understandable way. How else are we or cutters supposed to understand and visually get a handle on areas of agreement or disagreement among grading systems?

These charts and tables are a way, and I would argue the only way, for the cutters to get an understanding of how to optimize the cutting of rough to obtain the highest cut grade, in whichever cut grading system is chosen.

I have learned that many cutting houses are now cutting to a sweet spot range that is in common with all the major labs in an attempt to satisfy all buyers. That common range is found using charts like Sergey''s generated for each lab''s grading system.

Michael D. Cowing

 

[Serg]

Re: I have learned that many cutting houses are now cutting to a sweet spot range that is in common with all the major labs in an attempt to satisfy all buyers.

Michael,
Usually Cutting house has not know Him type end consumer ( chain is too big and it is not chain at all, it is tree ).
To reduce risk of marketing mistake cutter houses use intersections cutting grading systems from Major labs( for allocation they use intersection , for polish diamond they use integration of course to find most profitable grading report for this particular diamond) . It became standard practices in last year . Before AGS gold such intersection was very narrow. Because nobody know what system is correct and what consumer will want buy this particular diamond , Cutting houses should ADD NEW charts. It will dramatically reduce intersection zone .
Rules for cutters is more and more strict . It is not reasonable more at all.

( GIA EX, AGS Platinum 0 and AGS GOLD Ideal and may be even HRD H&A . Intersection for all these system is too too small !)

May be ASG had task to help cutters, to give more clear and easy rules. But result is new headache for cutters.

 

[strmrdr]

Date: 11/1/2008 1:35:06 AM
Author: michaelgem

It strains all credibility that, by using charts, someone can be accused of being intentionally misleading, by simply comparing grading systems in this visually meaningful, informative and understandable way. How else are we or cutters supposed to understand and visually get a handle on areas of agreement or disagreement among grading systems?

Please teach me how to tell what each of these RB diamonds looks like with only the following information.

A: 56T 40.8P 35C
B: 56t 40.8P 35c 75% lgf%
C: 56t 40.8P 35C 75% lgf% 55% stars

Cant be done because their are millions of variables each diamond could be cut to.

Simple fact... any 2D system is not accurate enough to duplicate a diamond with any degree of accuracy.
If you cant duplicate it you cant accurately model it.
The less accurate the model the less accurate any information gained from that model is.

Now your going to say but a 3d model is only as accurate as the scanner and the software that creates the model.
My answer yep!
At this time a 3D system isn't perfect but it a lot more accurate than a 2D system and can come very close to telling me what the above diamonds would look like.

To tell me that anyone can look at a chart and tell what any diamond looks like with any degree of accuracy is extremely misleading.

 

[strmrdr]

Lets take the reverse view that someone could use some tricks to make a very pretty diamond with ideal level light performance.
A chart based system would hammer it and not recognize it for what it is.

 

[Serg]

re:"Please teach me how to tell what each of these RB diamonds looks like with only the following information.

A: 56T 40.8P 35C
B: 56t 40.8P 35c 75% lgf%
C: 56t 40.8P 35C 75% lgf% 55% stars"

Karl,

Please take 56t 40.8P 35C 75% lgf% with any star in range 45%-55% and compare PGS results with 56t 40.8P 35C 75% lgf% 55% stars/

WHat PGS resilts will you receive ??

Same for girdle in range 2.5-4.5%

 

[strmrdr]

Date: 11/1/2008 5:56:58 AM
Author: Serg

re:''Please teach me how to tell what each of these RB diamonds looks like with only the following information.

A: 56T 40.8P 35C

B: 56t 40.8P 35c 75% lgf%

C: 56t 40.8P 35C 75% lgf% 55% stars''


Karl,


Please take 56t 40.8P 35C 75% lgf% with any star in range 45%-55% and compare PGS results with 56t 40.8P 35C 75% lgf% 55% stars/


WHat PGS resilts will you receive ??


Same for girdle in range 2.5-4.5%

I don''t have the PGS software to run that but...
With perfect optical symmetry and perfect tightness and no painting/digging and perfect roundness and all the other variables the same they would get the same grade.
But just from those numbers none of those things can be assumed nor are they possible in a real diamond.

 

[adamasgem]

Date: 11/1/2008 5:04:53 AM
Author: strmrdr

Date: 11/1/2008 1:35:06 AM
Author: michaelgem

It strains all credibility that, by using charts, someone can be accused of being intentionally misleading, by simply comparing grading systems in this visually meaningful, informative and understandable way. How else are we or cutters supposed to understand and visually get a handle on areas of agreement or disagreement among grading systems?

Please teach me how to tell what each of these RB diamonds looks like with only the following information.

A: 56T 40.8P 35C
B: 56t 40.8P 35c 75% lgf%
C: 56t 40.8P 35C 75% lgf% 55% stars

Cant be done because their are millions of variables each diamond could be cut to.

Simple fact... any 2D system is not accurate enough to duplicate a diamond with any degree of accuracy.
If you cant duplicate it you cant accurately model it.
The less accurate the model the less accurate any information gained from that model is.

Now your going to say but a 3d model is only as accurate as the scanner and the software that creates the model.
My answer yep!
At this time a 3D system isn''t perfect but it a lot more accurate than a 2D system and can come very close to telling me what the above diamonds would look like.

To tell me that anyone can look at a chart and tell what any diamond looks like with any degree of accuracy is extremely misleading.

Yup, you are 100% right Karl.

Just as throwing in "H&A" into discussions about AGS /GIA grading systems, while knowing full well that, while H&A require some level of higher symmetry, the rest of the H&A patterning criteria have nothing to do with ANY of the criteria considered by either of the AGS systems or the GIA system .

Intentionally misleading.

 

[michaelgem]

Karl,

I understand your point that charts cannot perfectly predict the grade that the PGS software will give an actual diamond. That is to say, a diamond that was cut to one of the charts cells, with the same constraints, by a human usually not capable of mathematical precision. In fact, my post mentions that the chart's grade should indicate the best possible grade such a diamond could obtain. That is assuming the PGS software's grading of the scanned diamond rewards precision and craftsmanship. (Another issue is the Sarin's scanning error resulting in a diamond model that is less than perfect even if the diamond had perfect optical symmetry)

And while I grant that a chart cannot tell you precisely what the diamond will look like, unless it is cut to the charts precision and constraints, in practice, cutters experience and GIA's visual testing show that following the charts will get you the grade and the diamond will perform at the grade. Just stay a safe distance away from the boundaries.

The principal use of charts is not to replace the PGS software, but to give us and the cutters a visual indication of the range of Ideal 0 under typical constraints and with perfect symmetry.

If a cutter wants to explore the range of Ideal with certain amounts of painting, reduced symmetry, or other non-standard constraints, he would have to generate a series of charts with these new constraints and analyze them for the new “sweet spot” range of Ideal.

As I said,

The cutter has to deal with a grading system based upon, not probabilistic confidence levels, but the deterministic presentation of that system in the form of charts like those of GIA, the AGS Gold and those that Sergey's cut grade task force has generated from the PGS software.

There is no other way I know of that the cutter can visually deal with such a multi-dimensional optimization problem, except to view 2-D slices of the 3-D space (table %, pav angle, crown angle) under his chosen constraints of fixed girdle %, star length, indexing, and half length.

A cutter has the best shot at an AGS Ideal 0 grade if he chooses table sizes around 56% where the greatest range of pav and crown angle combinations exist. In addition, to insure he gets the grade in spite of his lack of mathematical cutting precision, he should pick combinations in the heart of the Ideal sweet spot, sufficiently away from the boundaries.

Charts provide the cutter and us this very important function, which is why I said:

It strains all credibility that, by generating these charts, someone can be accused of being intentionally misleading, by simply comparing grading systems in this visually meaningful, informative and understandable way.

Michael D. Cowing

 

[Serg]

Date: 11/1/2008 10:39:00 AM
Author: strmrdr

Date: 11/1/2008 5:56:58 AM
Author: Serg

re:''Please teach me how to tell what each of these RB diamonds looks like with only the following information.

A: 56T 40.8P 35C

B: 56t 40.8P 35c 75% lgf%

C: 56t 40.8P 35C 75% lgf% 55% stars''


Karl,


Please take 56t 40.8P 35C 75% lgf% with any star in range 45%-55% and compare PGS results with 56t 40.8P 35C 75% lgf% 55% stars/


WHat PGS resilts will you receive ??


Same for girdle in range 2.5-4.5%

I don''t have the PGS software to run that but...
With perfect optical symmetry and perfect tightness and no painting/digging and perfect roundness and all the other variables the same they would get the same grade.
But just from those numbers none of those things can be assumed nor are they possible in a real diamond.

Re: But just from those numbers none of those things can be assumed nor are they possible in a real diamond
There are two tasks:
1) To Produce diamonds according cut grading system rules ( for example we have tasks to receive ASG 0 or GIA EX)
2) To Do cut grade

It could be strange for you but the methodology to cut diamond with so different goals for so different systems (GIA EX and ASG0) is exactly SAME!!

In both cases cutter house should

1. 1) Find manufacture tolerance for
   a. “Short” list parameters for GIA cut grading system( at least 49 parameters. but most probable I forgot few more parameters( 10-30 ))
   b. “Long” list parameters for AGS (Platinum) cut grading system (exactly same number of parameters like for GIA. May be I am wrong but I can not find any parameter what is important for AGS0 and does not important for GIA EX)
   2) Find Labs accuracy( deviation) for grading . accuracy labs scanners is JUST one cutter headache .
   3) Create cutters Guideline charts and rules
   a. GIA EX
   i. Create multidimensional database GIA Ex
   1. Build conservative zone with a account cutting tolerance , accuracy GIA scanners, accuracy GIA symmetry grade
   b. AGS O
   i. Exactly same . before Cutter houses received PGS software there was impossible to build reasonable Guidelines

Cutter houses did it and now they CAN ( not all of course. You need want it at least ) produce AGS 0 or GIA Ex with reasonable probability . (ASG 0 diamonds have reasonable range 3D symmetry . Diamond could be far from “True” H&A and have AGS 0 and of course PGS 0).
For most mathematical combination proportion from PGS0 database you can order to cut diamond and receive diamond with AGS 0 grade. Some Cutters can do it now. Does anybody argue it?

So 2D Charts Are Important and Adequate Instrument to Study and Compare AGS Platinum with other cut grading systems

It is pity what when Cutters receive enough experience ( after several years hard preparation) to Cut AGS 0, AGSL introduced AGS Gold what will downrange a lot of ASG Platinum 0

Cutter Houses who did not invest to tuning cutting technology according ASG Platinum rules will win now. Cutter Houses who invested in PGS Platinum production technology could lost big part some investments .

It was better( Cutters, consumers, AGS ) introduce firstly AGS Gold and than after few years AGS Platinum .
If AGS Gold came after AGS Platinum, ASG Ideal should include all AGS Platinum 0. ( there are other not very bad possibility)

 

[strmrdr]

Date: 11/1/2008 1:55:48 PM
Author: michaelgem

There is no other way I know of that the cutter can visually deal with such a multi-dimensional optimization problem, except to view 2-D slices of the 3-D space (table %, pav angle, crown angle) under his chosen constraints of fixed girdle %, star length, indexing, and half length.

There is a better way, use on the fly 3D calculations in the planning software taking into account cutting tolerance.
This is a perfect project for gpu acceleration and distributed computing.
A quad duel gpu sli card setup(8 gpus) could pull this off and if it cant more computers can be added using dnet clouds.
Each station would run under $7000
Computing power is cheap and this type of math and parallelization is what gpu''s were designed to do.

 

[strmrdr]

Date: 11/1/2008 5:45:00 PM
Author: Serg

a. GIA EX

i. Create multidimensional database GIA Ex

1. Build conservative zone with a account cutting tolerance , accuracy GIA scanners, accuracy GIA symmetry grade

b. AGS O

i. Exactly same . before Cutter houses received PGS software there was impossible to build reasonable Guidelines [/list]

..............

So 2D Charts Are Important and Adequate Instrument to Study and Compare AGS Platinum with other cut grading systems

multidimensional database does not translate into a 2D Chart.
There is no way to represent 49 parameters on a 2D chart.
.....
The 2D based ideal not only hurts cutters that invested in cutting to the 3D system it also harms consumers that learned to trust the AGS system.