Peter Yantzer, et al: Why a Two-Dimensional Cut Grading System is Passé

[pricescope]

Folks from AGS Lab (Peter Yantzer, Jason Quick, Jacob Sheffield, and Jim Caudill) submitted a new article: Why a Two-Dimensional Cut Grading System is Passé

Authors'' preface:

AGSL discontinued the proportion set based DQD on March 31 of this year. Now the only available DQD is the performance based version. Requests from industry members wanting us to define Ideal proportions prompted us to write this article. Just as some people still like to talk about a fine diamond being a 60-60, so too many people like to ‘hang their hat’ on a range of proportions. Change can cause fear or anxiety and it’s just human nature to not want to lose a grading system that they were comfortable using. With today’s technology, it is less accurate, impractical and virtually impossible to try and define a set of Ideal proportions. The examples in the article convincingly demonstrate this.

 

[strmrdr]

Thank You AGS.
Interesting stuff.

It does make official several things passed on from Peter in the recent thread on charts from AGS which is a good thing.

I'm looking forward to hearing more about the scint. images and studies.
They look interesting because it is the hardest area in diamond design to measure and to try and show it in static images is very very hard(cant show motion and scint. is motion), I would love too hear how/why AGS thinks they have pulled this off with those images.

 

[adamasgem]

I asked Peter for the STL files used in the article in a zipped format, and have sent them to Leonid for posting as the STL or zipped format is not usually allowed on PS.
Perhaps he can post them for DC users.
When I get a chance I'll try to do some work with them and show the comparative girdle profiles, which might be illustrative.
DC Renderings, and a comparative DC scoring will also be interesting..

Leonid just said he would upload the zipped file.. DC users can unzip the file to get the STL files and then import directly to DC..

 

[pricescope]

Here is the files Marty is talking about: https://www.pricescope.com/Article/AGSL/article_stl_files.zip. It contains a set of DiamCalc stereo vision files

 

[JohnQuixote]

 

[adamasgem]

Here is a comparison of DC cut quality compared to the AGS score.. I''ll get to the girdle profiles later...

 

[adamasgem]

Here is a scatter plot of the AGS cummulative light performance metric versus a summation of the three DiamondCalc metrics, light return mono, light return stereo and dark zone...

 

[Garry H (Cut Nut)]

I find this article is not up to the usual standard of AGS communications.

If it''s aim is to educate the trade dinasaurs who are stuck in 60:60 mode, then I think they need a re-write in far simpler language and minus the in-house jargon and secret codes.