Harding ASET similarity

[Garry H (Cut Nut)]

I just noticed the patterns in this chart from AGS for various crown and pavilion angles - see the similarity with Bruce Hardings revolutionary work from the mid 1970''s?

Click on the diamond chart at the boottom here
http://www.gemology.ru/cut/english/faceting/f5.htm#

To read the entire (brief and typically Bruce - to the point) article here:
http://www.gemology.ru/cut/english/faceting/index.htm

 

[Serg]

Thanks Gary,
You, AGS and Bruce gave me good idea.
We can code LR, Contrast, BlacZone by color and print on one page .( In future we can do it for B, F, S too)

 

[beryl]

Garry:
It took a lot of perception to see a resemblance between AGS'' ASET diagram and mine.
Actually, it looks more like MSU''s Fig. 1 (macroanalysis of light return nLR_30) in their first report of 1999(?), which is also at the same website; I recognize the AGS green fork from upper left as the MSU red one.
Note that the coordinate axes are reversed - AGS and MSU have pavilion vertical, whereas I had it horizontal. Both had a general trend from upper left to lower right (dexter bend) but to compare details meaningfully, it is necessary to reverse the axes of one of them.
I did this in DiamondTalk, circa 2001, and showed close correlation to this fork, except that the pavilion coordinates differed by about 1°. That is when Yuri Shelementiev pointed-out that this shift was due to the fact that, with 80% deep halves, the halves dominate pavilion reflection, rather than the mains, on which my chart was based. Subsequently I made this shift and the correlation was almost exact, whereby the principles described in "Faceting Limits" explained it.

 

[Garry H (Cut Nut)]

Date: 1/28/2006 2:04:40 AM
Author: Serg
Thanks Gary,
You, AGS and Bruce gave me good idea.
We can code LR, Contrast, BlacZone by color and print on one page .( In future we can do it for B, F, S too)

I get what you are suggesting Sergey

 

[Garry H (Cut Nut)]

Date: 1/28/2006 7:13:54 AM
Author: beryl
Garry:
It took a lot of perception to see a resemblance between AGS'' ASET diagram and mine.
Actually, it looks more like MSU''s Fig. 1 (macroanalysis of light return nLR_30) in their first report of 1999(?), which is also at the same website; I recognize the AGS green fork from upper left as the MSU red one.
Note that the coordinate axes are reversed - AGS and MSU have pavilion vertical, whereas I had it horizontal. Both had a general trend from upper left to lower right (dexter bend) but to compare details meaningfully, it is necessary to reverse the axes of one of them.
I did this in DiamondTalk, circa 2001, and showed close correlation to this fork, except that the pavilion coordinates differed by about 1°. That is when Yuri Shelementiev pointed-out that this shift was due to the fact that, with 80% deep halves, the halves dominate pavilion reflection, rather than the mains, on which my chart was based. Subsequently I made this shift and the correlation was almost exact, whereby the principles described in ''Faceting Limits'' explained it.

This is the link to the other chart that Beryl refers to I believe
http://www.gemology.ru/cut/english/podrobno_1.htm

 

[Garry H (Cut Nut)]

Also note that Beryl''s chart has the axes the other way round - but the diagonal lines still run more or less the same ways.

sorry about the quick and dirty job