Rhino''s Weekly Study ... Cut Grading Fancies

[Rhino]

Ok... last weeks experiment involved 1 of 2 adverse affects that negatively impact contrast brilliance. Thanks to all who participated. This weeks study involves an analysis of light return or brilliance within fancy cuts as examined with THE NEW GEM ADVISOR SOFTWARE via MSU.




MSU has recently updated their DiamCalc and Gem Advisor software and there are a couple of new features that are really neat.




One is that the IS image shown in the software correlates better to what is actually photographed and the other is that it now ASSESSES LIGHT RETURN WITHIN FANCY SHAPES!!!

That is good news for fancy shape lovers.




Ok... before we begin you''ll need to first download the latest Gem Advisor software and take these steps.

1. Go here ... http://www.cutstudy.com/download/GemAdviserSetup.exe download and install the software.
   
2. Now before you download any of the files I''ll be posting here you need to open up the Gem Advisor program once so Windows associates all .gem files with the program.
   
3. PLAY AND PRESS ALL THE BUTTONS in the program. It comes with a sample file of an ideal H&A cut. There are different light views to analyse the virtual diamonds under (my favorite is the disco lighting
   
   ) and you can also view how the stone will appear under an IdealScope, H&A scope among others. Another neat option is to put it in disco light and press the green play button to rock and tilt the virtual diamond before your eyes to get an idea of how fiery or not the diamond will be.

It''s easy to learn and play with and for those of you who love toys that give good information this is a real gas. It will automatically assess cut quality according to the model of the diamond imported into the program. This can be done manually via the DiamCalc program but we recommend actual scans of the diamonds in question since it is impossible to accurately input every facet angle on any diamond in question especially fancies.

Note: While it will be easy to compare and assess light return among the various shapes and others will certainly score higher than others, it is important to keep in mind that while a Regent will kick the pants off of say ... an oval ... this does not necessarily mean that you should not buy an oval. If your fiance loves oval diamonds *that''s what you should get her*. This is a great study and very educational but I would stress the importance of *seeing* the various shapes in person when possible then perhaps finding the most attractive diamond within the shape that your fiance loves.

Another note of interest. The grading is done on a linear scale. Ie. it is not comparing one particular shape on a scale that is comparitive with others of the same shape (like the BrillianceScope, although we can do that on the B''scope as well) but is comparing all shapes comparitively on the same scale. So if you wanted an idea of how the light return of a princess cut measures up to that of a top of the line H&A round ... you''ll see it reflected accurately in the score.

First attachment ... a cushion cut that just came in today which happens to be a very pretty stone amongst the world of "cushions". More shapes to follow.

 

[Rhino]

For reference here is a top of the line round.

 

[Rhino]

Here's a nice Asscher. Put this in disco lights and hit play.

Keep in mind that this does not necessarly mean that all Asschers are like this ... each stone varies depending upon proportions and symmetry.

 

[Rhino]

Here is a really nice oval. Note however the hit in the score. This is due to LARGE portions of light leakage within the diamond which you can easily see in the IdealScope image.

 

[Rhino]

Here is a Jubilee. I don't have to tell ya how much I love these stones but ... BOOYAH ... I told ya anyway.

 

[Rhino]

Here is a princess cut that was NOT hurting in the optical department. Note it's score vs the Jubilee though.

 

[Rhino]

Here's another optical powerhouse. The Regent.

 

[Rhino]

Here is an interesting rectangular princess. On the B'scope under the "rectangular" scale it scores incredible (which is softer on rectangulars) and among the world of "rectangular" princess cuts it is an outstanding stone but when compared on the linear scale it gives you a better idea when it falls within the grand scheme of things.

Just curious ... do ya'll prefer to see the various shapes all thrown into the same mix and graded on the same linear scale or do ya'll prefer to see each shape graded within it's own respective shape?

 

[Rhino]

Here is a round ... that well ... I'm not so excited about.

 

[Rhino]

Here is a pear brilliant. A very pretty stone among the world of pears.

 

[Rhino]

Here is a Lucere. Step cut crown with brilliandeered pavilion. Very cool.

 

[Rhino]

Radiant.

 

[Rhino]

And last but not least a Queen of Hearts. That's it for now. If there are any other shapes you'd like to see let me know and if I have it on file I'll be glad to post it. Have a great weekend everyone. Hope you enjoy.

 

[Stephan]

What a nice collection.
Thanx Jonathan!

 

[valeria101]

Cool

Nice to see the line up on the same scale of course! I didn't know Lucere had those eight arrows and four harts in the back...

 

[strmrdr]

----------------
On 5/15/2004 5:39:02 PM Rhino wrote:




Just curious ... do ya'll prefer to see the various shapes all thrown into the same mix and graded on the same linear scale or do ya'll prefer to see each shape graded within it's own respective shape?----------------

same scale!
But with a breakdown of where top of the line line for each shape falls on the scale.
Maybe like 2 pointers one showing where the diamond falls and another color arrow pointing to where the reference top of the line diamond of that shape ends up.

 

[valeria101]

Just one Q....

How does fire fit in your previously posted research about contrast brilliance ? As far as I understand, the pieces that appear dark in diffuse light also display less fire in just the conditions where it should show.

It's rather akward to place in context the "fire versus brilliance" discussion, when both qualities are summed up by the HCA and Bscope but only appreciated in contrasting lighting conditions. Could one say that the ideal proportions that you are trying to pinpoint deliver both but not in the same time (= not the same lighting conditions) while non-traditional round ideals would loose the balance between the two ?

 

[katbadness]

This is very cool, Rhino. Thanks for posting it..

----------------
On 5/15/2004 6:54:20 PM strmrdr wrote:

----------------
On 5/15/2004 5:39:02 PM Rhino wrote:

Just curious ... do ya'll prefer to see the various shapes all thrown into the same mix and graded on the same linear scale or do ya'll prefer to see each shape graded within it's own respective shape?----------------

same scale!

But with a breakdown of where top of the line line for each shape falls on the scale.
Maybe like 2 pointers one showing where the diamond falls and another color arrow pointing to where the reference top of the line diamond of that shape ends up.

----------------

What strmrdr said

.

This will be a nice comparison to see.

 

[Garry H (Cut Nut)]

Nice one Rhino.


This is what 3 of those stones might look like on their AGS report images next year

 

[Rhino]

----------------
On 5/15/2004 6:54:20 PM strmrdr wrote:

----------------
On 5/15/2004 5:39:02 PM Rhino wrote:








Just curious ... do ya'll prefer to see the various shapes all thrown into the same mix and graded on the same linear scale or do ya'll prefer to see each shape graded within it's own respective shape?----------------

same scale!
But with a breakdown of where top of the line line for each shape falls on the scale.
Maybe like 2 pointers one showing where the diamond falls and another color arrow pointing to where the reference top of the line diamond of that shape ends up.


----------------

Now *that* would be a good idea and very possible to do.

 

[Rhino]

----------------
On 5/15/2004 9:04:05 PM Cut Nut wrote:







Nice one Rhino.


This is what 3 of those stones might look like on their AGS report images next year

----------------

They'll be using the Gilbertson flavor Gary?

 

[Rhino]

Hi V,

Scroll down a tad.

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On 5/15/2004 7:21:10 PM valeria101 wrote:












Just one Q....

How does fire fit in your previously posted research about contrast brilliance ?

It doesn't because in diffuse light conditions the strength of the light is not intense enough to produce fire. Rule of thumb... the stronger the light condition the more you should see the phenomena of fire with an emphasis on scintillation. Scintillation can be observed in softer light conditions but stronger conditions flatter it more.

As far as I understand, the pieces that appear dark in diffuse light also display less fire in just the conditions where it should show.

Not that it would display less fire, it's just that fire is not observable in most diffuse light conditions. Where you begin to see fire or dispersion taking place within the diamond is ambient light conditions. The strength of the ambient light can produce a beautiful soft dispersion of rainbow within the diamond as well as white light return. Kinda like if you go outside, it's a sunny day out but you're standing in the shade, under a tree or suttin and natural daylight is falling onto the diamond yet the sun is not directly hitting the diamond.

It's rather akward to place in context the 'fire versus brilliance' discussion, when both qualities are summed up by the HCA and Bscope but only appreciated in contrasting lighting conditions.

No. B'scope, red reflectors, etc. do NOT and cannot assess the component of contrast brilliance discussed in the other thread. Remember there are 2 adverse affects ... the HCA and B'scope can assess one ... the effect of the steep/deep combo. Just not the shallow/shallow combo's.

Could one say that the ideal proportions that you are trying to pinpoint deliver both but not in the same time (= not the same lighting conditions) while non-traditional round ideals would loose the balance between the two ?

Correct ... they can deliver both but not at the same time unless you can pull off a feat of being able to have and observe the diamond in 2 lighting conditions at the same identical time. It is physically impossible.

----------------

The ultimate goal of that study is to find proportions that are the most beautiful not matter what light conditions you bring it into because you can have diamonds that excel in direct light conditions but not fare as well in diffuse and vice/versa.

Peace,

 

[Garry H (Cut Nut)]

Yeah - they think it will be understandable - But ?? what do you think Rhino?


No white leakage.


I think it is hard enough for people to learn what they see in the ideal-scope. But AGSL is a niche player.


They will also introduce a sliding scale for proportion combinations and fix the problem with steep deeps etc.


On the whole they will ensure that any stone they give a good grade on WIlL BE GOOD

 

[Rhino]

----------------
On 5/16/2004 2:27:23 AM Cut Nut wrote:







Yeah - they think it will be understandable - But ?? what do you think Rhino?


No white leakage.


I think it is hard enough for people to learn what they see in the ideal-scope. But AGSL is a niche player.


They will also introduce a sliding scale for proportion combinations and fix the problem with steep deeps etc.


On the whole they will ensure that any stone they give a good grade on WIlL BE GOOD

----------------

I don't want ppl to take this the wrong way but quite frankly Gary I think the Gilbertson model requires a learning curve that is way too steep. Sure people would be able to grasp it but not after much study. The red reflectors are *WAY* more easier to understand. I like the sliding scale idea as well. I wonder though if it would be to AGS' advantage to use a linear scale or a non-linear. I like the idea of linear becuase it has inspired cuts like the Regent, Queen and Jubilee. Did you see the Jubilee I posted up here in comparison to the H&A round?

 

[Stephan]

In disco lightening, I find the 1.01 H-SI2 better than the 1.05 E-VVS2...
Funny...

 

[Giangi]

This is, as always, a very nice and educative article, Jon. Thanks, it was really interesting!

 

[Rhino]

Thanks G and Kat!

Since meeting Serg, Yuri, Andrey and the whole team at MSU I've always been intrigued with their work and contributions to the industry. There is much to be gained from their research and a HUGE kudo's to them for putting together the software to make it possible. Steph, yes I see what you're saying regarding the 1.01ct. I think the same regarding the first cushion too although I like the 1.05ct better.

There are alot of dark areas in the 1.01ct in disco lighting that are bright in the 1.05ct. That's why it's good to compare when possible too of course.

 

[strmrdr]

on the subject of scales:
I like a 1-10 approach a lot better than meg high vh ect.

I love that asscher yummy!
Its the cut that is keeping me from becoming an RB freak lol

 

[Rhino]

----------------
On 5/16/2004 12:53:21 PM strmrdr wrote:

on the subject of scales:
I like a 1-10 approach a lot better than meg high vh ect.

I love that asscher yummy!
Its the cut that is keeping me from becoming an RB freak lol


----------------

Haha... yes that Asscher is YUMMY!

And yes.. the 1-10 approach is excellent but even better ... MSU breaks it all down to a 1 - 100 (or 120) approach which I like even better.

 

[strmrdr]

----------------
On 5/16/2004 1:40:50 PM Rhino wrote:

----------------

On 5/16/2004 12:53:21 PM strmrdr wrote:


on the subject of scales:

I like a 1-10 approach a lot better than meg high vh ect.


I love that asscher yummy!

Its the cut that is keeping me from becoming an RB freak lol



----------------

Haha... yes that Asscher is YUMMY!

And yes.. the 1-10 approach is excellent but even better ... MSU breaks it all down to a 1 - 100 (or 120) approach which I like even better.----------------

It depends on how the scal is reflected in the real world.
To a lot of people due to the way stuff is graded in school 70 out of 100 sounds worse than 7 out of 10 because 70% is seen as a failing grade or close to it.
Which might not be the truth depending on how the scale is reflected in appearance (pun intended)