AGS 2 or AGS 0 - The ''Candidate'' vs Parametric grades

[michaelgem]

Date: 2/27/2007 10:14:46 AM
Author: michaelgem

So the amount of context to include to clarify each thought is a trade off between trying to be brief and to the point, but still keep to a minimum the inevitable misinterpretation.

Michael

By the way, I marvel at Sergey''s ability, in spite of the language barrier, to put forward his logic and message in such a crisp clear manner.

Michael

 

[adamasgem]

Here is some food for thought..
The GUIDELINE charts were designed for cutters giving an idea that they were on the edge of a cliff..

Each point on the chart, really should represent a range, as the chart quantization is every 0.2 degrees

So I played with Diamond Calc last night to see what the implied slope was at the two conditions mentioned in the thread..

DiamondCalc has a 5 step qualitative grading and AGS an 1 step..

The baseline points (dark green) all got a DC VG rating with the numerics..

But note the slopes within a +/- 0.1 or +/- 0.2 degrees about the center point..(limitied by the rating quantizations)

Now , these are DC gradients which may or may not coincide with AGS gradients, but within 0.2 of a degree from the central point you can see DC going from VG to Good (0.9 boundary)

So to the complainers out there, go do the work yourself, look at the gradients for each AGS parameter WITHIN the quantization range...

Note that within the 0.2 degree quantization range of the DC rating system you have hills and valleys, would you not expect the same from the AGS system, not to mention that the MSU study didn''t address assymetries, but you can do some limited work on this from DC..

Or you can take 10000 or more random SRN scans and plug them through PGS to see what the average and standard deviation of the deductions and plot or tabulate the data about the quantized mean CA/PA point..

Information like that can tell you a lot..

Who wants to pay to do the work.. Any takers... Didn''t think so...

.

 

[Regular Guy]

Date: 2/27/2007 12:12:06 PM
Author: adamasgem

Each point on the chart, really should represent a range, as the chart quantization is every 0.2 degrees

Though I''ve only been following this thread for the sense, rather than the detail...here I can see some sense to go along with the resistance you''ve shared, Marty.

A few random observations...

a) This conversation has got to be a little like observing modern physics...is it particles or waves. Alternately, maybe it is more like beer: more taste, or less filling...

Still, and regardless, Michael, somewhere, the comments here should recognize the raison detre (sp?) of this thread, and give it some respect. Like Abbot''s Flatland...it''s got to be clear that 3 dimensions is better than two, and if the "land of the two" were to stand up and start to fight for its rights, or whatever, it would be in the context of understanding that 3 D modelling is a more complete approach. Marty''s point above tries to get at a third dimensional guy having a conversation with a 2 D guy, right?

b) somewhat related, but not too much...my work. Where I work, we publish research materials for accountants, and such, made available to professionals, and this material can go into text or web formats. If web (aka 3D), it''s always live, and could change, conceivably (but practically not) daily. In print, these are updated bi monthly or monthly, depending. The print format does "get it all..." i.e., no text is left out. And, there are procedures in place to see that any tinkering of the "live" document gets included in the print one...even though the text cannot, procedurally be integrated...it is set at front.

Not sure entirely how useful the example...but...if we''re to allow suggestions to AGS...and presume they owe something to cutters, by way of procedure...we would like to know they have some set of procedures to insure that...either on the basis of, like our company, on a regular schedule, they are advised of all changes...or in the alternative, if changes happen that are substantive enough, they would then provide such notification, so that a cutters work can articulate back to what later AGS will assuredly receive. You guys, including Serg, Michael, Marty, Garry & others have a good sense of this, no doubt.

c) In another post, Garry has in fact suggested he reads here that a "loosening" of category ranges may have changed since the original. Sounds like Marty questions this. Are matters of substance being discussed here...or matters of procedure? Marty may have laid the foundation for addressing this above....not sure.

Warm regards,

 

[michaelgem]

John makes my point about side issue diversions by coming up with the perfect red herring that diverts the discussion from the main message Sergey and I want AGS and those reading to consider.

The red herring of top-half painting to salvage a deep cut, swindled stone’s grade is a neat enough topic for its own thread. However, it is a diversion from the main point made so well and concisely by Sergey that I cannot improve upon it.

Yes, LAB can publish two type charts
1) First type: For ideal 3D symmetry diamonds
2) Second type: Guideline for cutters that take into account the cutting accuracy.


The second type of chart should satisfy at least these next conditions:
a) They should mention tolerances for cutting. Manufactures have quite different levels of technology. For what level of manufacturing tolerance did AGS publish its guideline charts?
b) For each set of parameters, the grade listed in the second type of chart should be the same or worse than the grade in the first type of chart.

If the guideline charts do not satisfy the first condition, they are very misleading charts.
If the guideline charts do not satisfy the second condition, they are wrong charts.

The AGS guideline charts are wrong and misleading at the same time. Sergey


Michael Cowing

 

[adamasgem]

Date: 2/27/2007 1:24:15 PM
Author: michaelgem

John makes my point about side issue diversions by coming up with the perfect red herring that diverts the discussion from the main message Sergey and I want AGS and those reading to consider.

The red herring of top-half painting to salvage a deep cut, swindled stone’s grade is a neat enough topic for its own thread. However, it is a diversion from the main point made so well and concisely by Sergey that I cannot improve upon it.

And who brought up the red herring, which escalated becuase of misquotes out of context, and which I believe Peter sent you information that disproved it..

But since the proof Peter sent you was in your hands BEFORE your last post, I wonder why you don''t see fit to correct yourself. What is the agenda?

Isn''t painting or digging just another pertubation from baseline that has to be considered, and is considered in the AGS system via raytracing to see the effects, not arbitrarily dinging them.

Date: 2/26/2007 9:14:56 PM
Author: michaelgem
You know that Peter has said that painting and digging lead to deductions and certainly not to a better grade.

RE: The AGS guideline charts are wrong and misleading at the same time. Sergey

Since you obviously support Sergeys thesis, why don''t YOU do the pertubation analysis and publish your own...

THE charts are conservative guidelines, nothing more, nothing less... They are telling the cutter they are getting into regions where they could start getitng more than the average cutting fault deductions.

 

[Serg]

Date: 2/27/2007 1:52:13 PM
Author: adamasgem

Date: 2/27/2007 1:24:15 PM
Author: michaelgem



....

THE charts are conservative guidelines, nothing more, nothing less... They are telling the cutter they are getting into regions where they could start getitng more than the average cutting fault deductions.

Marty,

What is your definition of “conservative guidelines”?

For my opinion Charts can not be “conservative guidelines” if some points from these charts have grade better then same points from Charts without any deductions.
Why do you carefully ignore such fact and try take away discussion from main issue?
I am understanding the problem create correct “conservative guidelines” very well.
But it is quit different issue.

 

[JohnQuixote]

Date: 2/27/2007 1:24:15 PM
Author: michaelgem

John makes my point about side issue diversions by coming up with the perfect red herring that diverts the discussion from the main message Sergey and I want AGS and those reading to consider.

Michael, I’m disappointed by your comportment.

As you know, Peter Yantzer (aware of these discussions) ran simulations last night.He demonstrated that the assumptions stated here re; brillianteering and deductions-only were incorrect.He was generous with the info and extended permission for us to publish the results here.As a courtesy to you I did not post them; I trusted your integrity in reporting the correction.

Instead, it looks like you are now dismissing the subject as a “red herring” although you made the statements leading to a need for correction.Even if you feel they depart from the main issue the facts bear reporting.

As for your “main message,” I believe everyone understands the premise.Nothing is stopping further discussion.In fact, I addressed your “main message” before here.I stopped contributing after page 2 but will join again if I have something I feel is worth saying.

You called for me this morning and left a message with our receptionist.Was the above what you wanted to discuss?I returned the call but you did not pick up.I’m back from lunch and you are welcome to try me again.

 

[michaelgem]

Some continue to project motivations as to my and Sergey’s purpose in requesting an update to the AGS guideline charts.

Here is a summary of my and Sergey’s motivations:

1. Cutters wishing to have their diamonond’s blessed by both AGS and GIA are now cutting to the intersection of the GIA charts and the current outdated AGS guideline charts. This intersection is unnecessarily restrictive as we see in examples like P41cr35t56, which Peter has informed me is an AGS Ideal 0, while the charts give it an AGS 2.

If I am a cutter walking the Ideal 0 line, I have a better chance of not falling off if I know where the edge is. Even if that edge is predicated on a mathematically symmetric stone. IMO It should be up to the cutter, knowing his own skill level, not AGS, to decide how close to the edge he should play. He can''t do that if he is not told where the Ideal 0 edge is.

2. Sergey answers the question: What is the agenda?
It is to get the official answer from AGS whether the following are AGS Ideal 0 (or AGS 3):
6 mm 80 LG P41 Cr35 T57
1) Girdle( In bezel) 3% Star 50%
2) Girdle( In bezel) 3.5% Star 50%
3) Girdle( In bezel) 3% Star 55%
4) Girdle( In bezel) 3.5% Star 55%
I will try to give a more full explanation.
Yes, LAB can publish two type charts
1) First type: For ideal 3D symmetry diamonds
2) Second type: Guideline for cutters that take into account the cutting accuracy.
The second type of chart should satisfy at least these next conditions:
a) They should mention tolerances for cutting. Manufactures have quite different levels of technology. For what level of manufacturing tolerance did AGS publish its guideline charts?
b) For each set of parameters, the grade listed in the second type of chart should be the same or worse than the grade in the first type of chart.

If the guideline charts do not satisfy the first condition, they are very misleading charts.

If the guideline charts do not satisfy the second condition, they are wrong charts.

The AGS guideline charts are wrong and misleading at the same time.

I understand the political answer from AGS (It is just for cutters, we just want to do good service).

I am not pro AGS or pro GIA. I try to keep an open mind.
Each person and company make mistakes, it is normal. The important thing is how you fix your mistakes. Sergey

3. In my writing I have endeavored to fairly and accurately represent the AGS range of Ideal 0. Now that AGS has informed us that this range has increased from the initial range represented in the charts, it appears in their interest to clarify this new range of Ideal 0 by updating those charts. Then the cutters could more accurately work with the true AGS extent of the Ideal 0 proportions.

Michael Cowing

 

[michaelgem]

Just talked to John Pollard, and quickly realized that my red herring comments were out of line, as he had taken them personally. So I want to apologize to him and anyone else who felt that way.

As is probably obvious, my use of the expression ‘red herring’ grew out of my frustration with having to address side issues that Sergey and I see as distractions from the main issues that my previous post summarized.

Sorry, John

Ideal regards,

Michael

 

[JohnQuixote]

Date: 2/27/2007 4:49:20 PM
Author: michaelgem

Just talked to John Pollard, and quickly realized that my red herring comments were out of line, as he had taken them personally. So I want to apologize to him and anyone else who felt that way.

As is probably obvious, my use of the expression ‘red herring’ grew out of my frustration with having to address side issues that Sergey and I see as distractions from the main issues that my previous post summarized.

Sorry, John

Thank you Michael.

I have no objection to the continued pursuit of clarity here. Your latest post (4:15:52 PM) lists some clear goals. A separate thread to discuss the influence of creative brillianteering as it relates is a good suggestion.

I appreciate you taking the time to contact me directly. Cheers.

 

[michaelgem]

Date: 2/27/2007 5:11:20 PM
Author: JohnQuixote

Date: 2/27/2007 4:49:20 PM
Author: michaelgem

Just talked to John Pollard, and quickly realized that my red herring comments were out of line, as he had taken them personally. So I want to apologize to him and anyone else who felt that way.

As is probably obvious, my use of the expression ‘red herring’ grew out of my frustration with having to address side issues that Sergey and I see as distractions from the main issues that my previous post summarized.

Sorry, John

Thank you Michael.

I have no objection to the continued pursuit of clarity here. Your latest post (4:15:52 PM) lists some clear goals. A separate thread to discuss the influence of creative brillianteering as it relates is a good suggestion.

I appreciate you taking the time to contact me directly. Cheers.

I had been trying to call John since this morning when we both received emails from Peter offering a case similar to the one John posted. I wanted to talk to him before posting or deciding he should post it.

This was indeed a case where the grade of an AGS 2 got elevated to a 1 by playing with different amounts of top-half painting.

Peter invited us to post this combination, which adds to John’s observations that crown painting can make a positive grade impact as well as the more usual negative impact.

Hopefully, (but I would not bet on it), this will not divert from the previously stated main message of Sergey’s and mine.

If I am reading this correctly, correct me if I am not, it looks like the diamond with the painted crown-halves had less deduction for brightness, while neither had a deduction for dispersion. The implications for the cutters makes for another great thread, which because he brought it to our attention and because of his insight, would best be started by John.

Michael