Simple Science: Is shallow or deep better?

[beryl]

Replying to Garry:
"Where can we find this?" ("Facet Designer" software by Anton Vasiliev) ...
On AGS discs, labeled "What to Do if You Can't Open These Files" (unfortunate label).
Or I can e-mail it. I sent it to you Garry; I think you missed its value.
There are also supplemental Tips & Newsletters, available from me at [email protected] or Anton at [email protected]. I sent you some of these, Garry.

"The tilt would not change the angular relationships would it" (re stereo illustration)
Yes, it does, but not significantly. This is how Anton improved my work in "Faceting Limits". His smaller 'good' zones are provided in his software "Plimit", available from him or me, and in the article 'Optimizing Faceting for Beauty" in the 'Russian Gemological Bulletin", 2002, 5(2), 33-41 and later, in English, in "The Journal of Gemmology", Vol.29, No.1, Jan, 2004, pp.25-36. I can e-mail a copy of the manuscript for the latter.

"How Come These Russians are so Brainy"?
Much of the work originated with Anton; credit is often omitted. Recall his name at the bottom of the MSU charts of 1998. His business is cutting colored stones but the principles apply to diamonds as well, except that color and double-refraction effects are not required there - diamonds are much easier to analyze optically. Too bad you missed the visit to his shop during the IDCC in 2004.

Here is an illustration from the sequel to Anton's article mentioned in the first paragraph above: "Influence of the Observer on a Gem's Appearance", "Russian Gemological Bulletin", 2002, 3(6),3-8. Sadly, the British Journal declined the translation of this article, but I can e-mail a copy of the manuscript to anyone who wants it.
The dots on the surface of the sphere are where light rays from various sources, that reach the viewer's eye, would penetrate the surface of the sphere. For example, a dot in a green area would appear green on the gem's surface, to the viewer.
The article shows various patterns of the environment (with and without viewer head and/or body) in the face-up view of the gem and discusses what I mentioned earlier about distribution of the environment according to the cut.

 

[beryl]

Here is a typical illustration from Anton's sequel = Fig.5. It is of a stone with RI=1.78 (sapphire or almandite garnet) having 42° pavilion mains and 39° crown mains - at left with viewer's head but without viewer's body, at right with viewer's body added.
Using "Facet Designer" you can do the same thing for diamond. In fact I think I will and send it here if/when time permits.

 

[beryl]

Here is Fig.4, which shows the environment of the stone above. Note all the white dots on the viewer = light sources which will appear black on the gem's surface. Note the blue sky, which appears mostly on one side of the gem in the picture above; this can be distributed more evenly around the stone by choosing different main facet slopes, as is seen in other illustrations of this article.

 

[Garry H (Cut Nut)]

Bruce Drena and I went to Anton''s a year or 2 before the Diamonc Cut Conference and I saw some of this work.
He obviously has extended it further.

I found the user interface on the software that you sent thru too difficult - but then i have never been able to master GemCad (I think I have a mental design defficiency

)

I would like to see the newest manuscript please.
In fact if anton would agree then I am certain Leonid would be very happy to publish it here in the Journal section.