What procedures to follow when reflectors cannot (any longer) help?

[Serg]

Date: 7/30/2009 10:19:46 AM
Author: Stone-cold11

Date: 7/30/2009 10:04:39 AM
Author: Serg

Date: 7/30/2009 8:41:26 AM

Author: Stone-cold11

One question about the ASET, is there a difference between a black background ASET and a white background ASET? Similar usage? If same, why would one want to use one over the other or why present both in the image?

Thanks.

Black ASET does not show Leakage.

White ASET has too much colors for my Taste( too complex image)

Distribution is more clear in Black ASET,

So what does the black in the Black ASET represents? Thanks.

1) Black is Leakage + lens obscuration
2) leakage is muc more visiable in white ASET. Just compare dull green in Black ASET and with sane place in white ASET
Black ASET is more correct for cut "grading" than white ASET
White ASET is more useful for cut improving
3) ask ASGL or John Pollard

 

[stone-cold11]

Date: 7/30/2009 10:36:57 AM
Author: Serg
1) Black is Leakage + lens obscuration

2) leakage is muc more visiable in white ASET. Just compare dull green in Black ASET and with sane place in white ASET

Black ASET is more correct for cut ''grading'' than white ASET

White ASET is more useful for cut improving

3) ask ASGL or John Pollard

I thought the lens obstruction is Blue color coded?

 

[Serg]

Date: 7/30/2009 10:47:44 AM
Author: Stone-cold11

Date: 7/30/2009 10:36:57 AM
Author: Serg
1) Black is Leakage + lens obscuration

2) leakage is muc more visiable in white ASET. Just compare dull green in Black ASET and with sane place in white ASET

Black ASET is more correct for cut 'grading' than white ASET

White ASET is more useful for cut improving

3) ask ASGL or John Pollard

I thought the lens obstruction is Blue color coded?

Who could you see white, green, red in such case?
blue does not cover whole lens

 

[Regular Guy]

Well, this is all very interesting.

Date: 7/30/2009 1:43:58 AM
Author: Serg
Hi Ira,
To find new fancy cut for MSS , shortly I use below method:
1) 3D model level
A) check LR and ETAS. If both below 0.8 I usualy reject diamond, but if this diamond has highest recomendation from person who sent me it I continue process
B) IS, ASET, Black zone metrics. I check distribution of black zones. If diamond has clear and big black zones , I do movies to check is it static black zones?
C) comparision movies with RBC AGS&H&A in two light iluminations
D) DETAS comparision
E) ray tracing study. Check cross ray ability
If diamond pass all these tests I buy it or order cutting.
2)After we recieve real diamond,check again 3D model then:
A) comparision movies in two light illuminations with RBC(MSS13)
B) visual comparision tests( several persons, several samples, several light types)

This probably answers the question, and could be teased out for understanding.

Dave Atlas adds perspective. First thought is that while Dave''s approach may provide good reality testing, it may not provide a good enough threshold go/no go approach, making the spectrum of nuance desirable...given a multi-thousand dollar purchase. At least for Joe Schmo shopper. Then again...it''s not clear Joe will on his own engage Sergey''s strategies, either.

 

[Serg]

Date: 7/30/2009 10:55:25 AM
Author: Serg

Date: 7/30/2009 10:47:44 AM
Author: Stone-cold11

Date: 7/30/2009 10:36:57 AM
Author: Serg
1) Black is Leakage + lens obscuration

2) leakage is muc more visiable in white ASET. Just compare dull green in Black ASET and with sane place in white ASET

Black ASET is more correct for cut ''grading'' than white ASET

White ASET is more useful for cut improving

3) ask ASGL or John Pollard

I thought the lens obstruction is Blue color coded?

Who could you see white, green, red in such case?
blue does not cover whole lens

Re:Who could you see white, green, red in such case?
How could you see white, green, red in such case?

 

[stone-cold11]

Date: 7/30/2009 11:50:23 AM
Author: Serg
Re:Who could you see white, green, red in such case?

How could you see white, green, red in such case?

Ok, that makes sense. Thanks.

 

[strmrdr]

In Serg's list this goes in part B


When I am designing diamonds I break contrast into 2 parts.
Hard and soft.

Hard contrast is contrast that stays nearly the same over tilt and or distance.
This in fancies can kill fire and scintillation.
The virtual facet rarely if ever fires off light to the viewer.
Another term for it would be a persistent dark zone.
This is why I love videos for fancies, either under a scope or without.
This is also why when looking at diamonds under the aset live you should tilt them back and forth.
When a round brilliant is said to have contrast issues it is a diamond that has persistent dark zones over distance.

Soft contrast goes away and or changes quickly under tilt and the virtual facet fires light back to the viewer.
It also changes with distance.

The contrast can be leakage or obstruction.

This is also why I like to have multiple images when I cant have video because they will always be at a slightly different tilt.

 

[strmrdr]

Date: 7/30/2009 9:15:13 AM
Author: Garry H (Cut Nut)

And another feature that is hard to describe - but i will try in the next few days - is that sometimes a stone can have an entire dark zoe thru a range of movements because of obstruction.

This is what I would term hard contrast.
Jon has a video of an asscher that shows it very well.
I don''t have a link at the moment.

 

[oldminer]

It is truly amazing how over the top and complex this subject can become. What I see emerging is some sort of strategy which would well apply to the creation of finely cut and high performing diamonds, but something way too complex for "grading" diamonds. Grading is normally done under a rather simple lighting scenario, with an eye toward repeatabily, accuracy and consistency within this limited scenario only. The rest, the subjective and important judgment of personal beauty is done in as many environments as you have time to study the diamond in. Beauty appreciation is a separate thing from "grading".

So long as the understanding of these two elements, both highly important to diamond dealers and to consumers, are kept in separate arenas, this topic is not going off course. If anyone thinks that "grades" will arise from such complexity, I have serious doubts about it ever happening. We will have far better looking and more interesting diamond cuts based on these new techniques which are something to look forward to.
Surely, some elementsw of this high tech stuff will find their way to the grading labs in due course, but it will be a selective few bits, not the entire mass of this growing knowledge base.

I am more oriented around "grading", but there are many here who have design and beauty as their higher goals. Great thread!

 

[lisa1.01fvs1]

Lorelei good to be back, I can't stay away too long.............had 2nd baby & a lot going on

Can't one or all of you guys come with me to pick out the Novo???

Now I'm even more flumoxed (sp) than ever!!!!!

This ASET use for the novice consumer is daunting. I will certainly bring it in to T to check stones!!!

CCL - I can barely keep up with your exemplary explanations on cushions (other threads) but hope to consult you further about things. Yes I know that GOG
has sq. H&A cushions and that the pricing is also fairly steep for those.
The Novo is an upgrade and I could probably get above 1.5 cts or 1.6 in a G/VS2 or therabouts.
Thought I'd go with the patented cut this time since we are already invested so to speak & am convinced I can get a fab RB elsewhere down the line

 

[strmrdr]

The bottom virtual diamond has large hard contrast zones over 5 degrees of tilt.
The top one does not.
The top diamond would be much more lively and pleasing to the eye.

 

[Regular Guy]

Date: 7/30/2009 1:23:50 PM
Author: oldminer
It is truly amazing how over the top and complex this subject can become. What I see emerging is some sort of strategy which would well apply to the creation of finely cut and high performing diamonds, but something way too complex for ''grading'' diamonds. Grading is normally done under a rather simple lighting scenario, with an eye toward repeatabily, accuracy and consistency within this limited scenario only.

I don''t know Dave, and forgive me if my understanding is off, but I''ll take a stab at repeating what I''ve read.

There''s a difference between defining grading as how it is normally done, and historically done. I think AGS is a big enough player, to call their contemporary practice authoritative. I think they do capture an aset view, and then do many (90?) rotations. Is this the same, different, or consistent with doing a movie? I think it''s consistent with it. And is a strategy for appreciating a different result of light performance from different positions. This is current practice, based on, as I understand it, the need to grade, based on evaluating the diamond in different positions, rather than a static one, at least...

 

[Serg]

Date: 7/30/2009 1:13:59 PM
Author: strmrdr

Date: 7/30/2009 9:15:13 AM
Author: Garry H (Cut Nut)

And another feature that is hard to describe - but i will try in the next few days - is that sometimes a stone can have an entire dark zoe thru a range of movements because of obstruction.

This is what I would term hard contrast.
Jon has a video of an asscher that shows it very well.
I don''t have a link at the moment.

Garry, good example for small such phenomena is some AGS0 princesses with 4 or more shevrons
Angles between shevrons are 1-2 degree and very often you can receive angles between opposite facets in range 44-46 degree. It creates 4 static black squares.

 

[diagem]

Date: 7/30/2009 1:43:58 PM
Author: Serg

Date: 7/30/2009 1:13:59 PM
Author: strmrdr

Date: 7/30/2009 9:15:13 AM
Author: Garry H (Cut Nut)

And another feature that is hard to describe - but i will try in the next few days - is that sometimes a stone can have an entire dark zoe thru a range of movements because of obstruction.

This is what I would term hard contrast.
Jon has a video of an asscher that shows it very well.
I don''t have a link at the moment.

Garry, good example for small such phenomena is some AGS0 princesses with 4 or more shevrons
Angles between shevrons are 1-2 degree and very often you can receive angles between opposite facets in range 44-46 degree. It creates 4 static black squares.

Painting effect?

 

[Rockdiamond]

I agree with David Atlas- this thread has gotten extremely technical.

If the purpose is to discuss alternative methods, maybe we should start a new thread on that subject.

The title of the thread indicates that one must first exhaust reflector technology to find another method.
I respectfully suggest that the professionals who don''t use reflector technology are generally not doing so because they felt reflector technology could no longer help them- they never used it in the first place.

I also want to stress that it''s not a question of which is "better"- and that if I advocate the use of methods that do not include reflector technology it should in no way be seen a s a knock against reflector technology.

 

[diagem]

Date: 7/30/2009 1:23:50 PM
Author: oldminer
It is truly amazing how over the top and complex this subject can become. What I see emerging is some sort of strategy which would well apply to the creation of finely cut and high performing diamonds, but something way too complex for ''grading'' diamonds. Grading is normally done under a rather simple lighting scenario, with an eye toward repeatabily, accuracy and consistency within this limited scenario only. The rest, the subjective and important judgment of personal beauty is done in as many environments as you have time to study the diamond in. Beauty appreciation is a separate thing from ''grading''.

I believe consumer demand drives for better (or finely) cut Diamonds..., these tech tools play a role in the education aspect of building consumer demand for better cuts. I think we should understand by now that a Diamond cant be fully judged by still images (actual or reflection tech.) only! Beauty is a whole other aspect..., I believe you need to visualize a Diamond in 3D and in *free* motion to realy appreciate its beauty. Dave..., I think your writing realy reflect the true issue here..., nice

So long as the understanding of these two elements, both highly important to diamond dealers and to consumers, are kept in separate arenas, this topic is not going off course. If anyone thinks that ''grades'' will arise from such complexity, I have serious doubts about it ever happening. We will have far better looking and more interesting diamond cuts based on these new techniques which are something to look forward to.
Surely, some elementsw of this high tech stuff will find their way to the grading labs in due course, but it will be a selective few bits, not the entire mass of this growing knowledge base.

And these few bits will be used to better market and differentiate Lab *branding*...., I am not sure it will make grading more efficient.

I am more oriented around ''grading'', but there are many here who have design and beauty as their higher goals. Great thread!

I tend to lean towards the highlighted part..., but do agree its an interesting thread!

 

[Rockdiamond]

How about this part: Is a stone graded EX by GIA( or an AGS0) better than a stone of VG cut grade necessarily?
If we can use reflector technology to prove one diamond returns more light, we can say that''s a scientific fact.
However saying one is better calls for subjective assessment.
Otherwise we could say RBC is better than any other cut.

 

[Rockdiamond]

Date: 7/29/2009 3:47:57 PM
Author: Regular Guy

....so, despite the shortcomings of this method, where you filter by desired color & clarity, eliminating those you weren''t looking for...there is otherwise NO other front end filter. You look at each one.

Yes Ira- If it''s my money, I look at each and every one.
Remember that ANY method will have drawbacks.


Also- if two well trained diamond buyers- each concentrating on high quality of cut- looked through 100 cushions to buy 10....do you think they would necessarily pick the same 10?


Sharon- Yes- I have purchased diamonds in Ramat Gan Israel on many occasions.

 

[Regular Guy]

Date: 7/30/2009 2:15:32 PM
Author: Rockdiamond
I agree with David Atlas- this thread has gotten extremely technical.

If the purpose is to discuss alternative methods, maybe we should start a new thread on that subject.

The title of the thread indicates that one must first exhaust reflector technology to find another method.
I respectfully suggest that the professionals who don''t use reflector technology are generally not doing so because they felt reflector technology could no longer help them- they never used it in the first place.

I also want to stress that it''s not a question of which is ''better''- and that if I advocate the use of methods that do not include reflector technology it should in no way be seen a s a knock against reflector technology.

David I''d recommend you first review the first panel of this thread to see there''s no need to avoid getting technical...nor to start another thread...and if you wish, for background, re-read Serg''s comments in the latter part of the other very long contemporary thread on bias, since they provided the primary background for this thread. Both you and Serg, as I outlined at the beginning of this thread, might take the position that reflector technologies aren''t sufficient to make a purchase decision. Serg would say using them to filter first is reasonable, and you would not...but both of you present the suggestion that some other protocol is necessary, ultimately.

Getting at what that other protocol is was my query. You''ve said it''s eyes, eyes, eyes, I think...probably, coupled with experience. I think that Serg is concurring, but will bootstrap available expert systems to assist. Regarding the latter (as well as the former...how reflectors can help), there''s just more to talk about.

Understanding how resources can be enabled to help make a purchase decision is very much what this thread is about.

 

[Garry H (Cut Nut)]

Date: 7/30/2009 10:55:25 AM
Author: Serg

Date: 7/30/2009 10:47:44 AM
Author: Stone-cold11

Date: 7/30/2009 10:36:57 AM
Author: Serg
1) Black is Leakage + lens obscuration

2) leakage is muc more visiable in white ASET. Just compare dull green in Black ASET and with sane place in white ASET

Black ASET is more correct for cut ''grading'' than white ASET

White ASET is more useful for cut improving

3) ask ASGL or John Pollard

I thought the lens obstruction is Blue color coded?

Who could you see white, green, red in such case?
blue does not cover whole lens

In the DiamCalc images blue does cover the entire ''virtual lens''.
In the hand held version I made for AGS, that is also included as the operational component in theier desk top showroom unit, the lens hole is very small.

I believe there is some larrger lens black in some of the AGS units used for photography - so in the case of photo''s from vendors it could be true that leakage and obscuration could be mixed together.

Unlike Sergey, I prefer the white leakage version because I use it very often and perhaps I have become very familiar with it.
But remember I rock the stone so i see a lot more with it (rocking the stone is next to impossible with black ASET)

The first image shows a default DiamCalc princess that shows the "hole in the middle" that is almost always visible to the naked eye (even allowing for stereo vision). with ASET black this is very often missed.

 

[Garry H (Cut Nut)]

Date: 7/30/2009 1:38:24 PM
Author: Regular Guy

Date: 7/30/2009 1:23:50 PM
Author: oldminer
It is truly amazing how over the top and complex this subject can become. What I see emerging is some sort of strategy which would well apply to the creation of finely cut and high performing diamonds, but something way too complex for ''grading'' diamonds. Grading is normally done under a rather simple lighting scenario, with an eye toward repeatabily, accuracy and consistency within this limited scenario only.

I don''t know Dave, and forgive me if my understanding is off, but I''ll take a stab at repeating what I''ve read.

There''s a difference between defining grading as how it is normally done, and historically done. I think AGS is a big enough player, to call their contemporary practice authoritative. I think they do capture an aset view, and then do many (90?) rotations. Is this the same, different, or consistent with doing a movie? I think it''s consistent with it. And is a strategy for appreciating a different result of light performance from different positions. This is current practice, based on, as I understand it, the need to grade, based on evaluating the diamond in different positions, rather than a static one, at least...

Ira my understanding is that the AGSL system will not identify a dark zone that does not turn off - it just looks at the total stone effect - where as we are looking at features the human eye can decide are ugly.

 

[Garry H (Cut Nut)]

Date: 7/30/2009 1:43:58 PM
Author: Serg

Date: 7/30/2009 1:13:59 PM
Author: strmrdr

Date: 7/30/2009 9:15:13 AM
Author: Garry H (Cut Nut)

And another feature that is hard to describe - but i will try in the next few days - is that sometimes a stone can have an entire dark zoe thru a range of movements because of obstruction.

This is what I would term hard contrast.
Jon has a video of an asscher that shows it very well.
I don''t have a link at the moment.

Garry, good example for small such phenomena is some AGS0 princesses with 4 or more shevrons
Angles between shevrons are 1-2 degree and very often you can receive angles between opposite facets in range 44-46 degree. It creates 4 static black squares.

Sergey could you please do an image (send me an email if you are still away) or give us a better description?

 

[Rockdiamond]

Thanks Ira.
Do we agree that the title- implying that other methods are a "last resort" is inaccurate?


The question I raised about picking- and how different experienced people looking at the same selection of stones with cut in mind will pick different ones- what's the feeling about that?


See, part of the danger in having different methods, and quantifying which is "better" can lead to misunderstanding.
Say jeweler A uses ASET/IS in his purchase decisions.
Nothing wrong with that at all.

Say jeweler B uses more traditional methods- looking through cutter's or dealer's inventories and using the visual aspects to pick the ones he/she prefers.
If a consumer feels ASET is the way to go based on some of the PS discussions, and stops into jeweler B, misunderstandings can occur.
Jeweler B picked what they knew to be very well cut diamonds, yet after submitting to the test requested by the consumer it seems that jeweler B is offering "lesser" cut diamonds.
That's why I say it's important not to put one method as "better" than another.

 

[Garry H (Cut Nut)]

Date: 7/30/2009 8:57:50 AM
Author: Ellen

Date: 7/30/2009 8:28:20 AM
Author: Lorelei
VERY cool Sergey and Garry - like the scarf example too!

Ok, I feel like I''m playing ''Where''s Waldo''. lol I have read, and reread, I cannot find the scarf!

I can find a spoon though....

Very interesting Serg and Gary!

Gary, I will guess the top pear is the better?

Ellen here are the DiamCalc scores (some are only available in the Pro software).
the numbers are:
1. light return mono
2. ETAS for light return
3. ETAS for fire
4. ETAs for fire X DETAS
5. DETAS

These are not commonly used functions for cut grading - but you will be interested in the numbers. (bigger is likely to be better).

 

[Rockdiamond]

Date: 7/30/2009 1:43:58 AM
Author: Serg
Hi Ira,

To find new fancy cut for MSS , shortly I use below method:

1) 3D model level

A) check LR and ETAS. If both below 0.8 I usualy reject diamond, but if this diamond has highest recomendation from person who sent me it I continue process

B) IS, ASET, Black zone metrics. I check distribution of black zones. If diamond has clear and big black zones , I do movies to check is it static black zones?

C) comparision movies with RBC AGS&H&A in two light iluminations

D) DETAS comparision

E) ray tracing study. Check cross ray ability

If diamond pass all these tests I buy it or order cutting.

2)After we recieve real diamond,check again 3D model then:

A) comparision movies in two light illuminations with RBC(MSS13)

B) visual comparision tests( several persons, several samples, several light types)

There's no way to describe how much respect I feel for Serg- and Garry.
What people like me do naturally, using "low tech" methods has been studied by Garry, Serg and others in an attempt to standardize things
But saying this is not highly technical?

 

[Garry H (Cut Nut)]

Date: 7/30/2009 5:00:55 PM
Author: Garry H (Cut Nut)

Date: 7/30/2009 8:57:50 AM
Author: Ellen

Date: 7/30/2009 8:28:20 AM
Author: Lorelei
VERY cool Sergey and Garry - like the scarf example too!

Ok, I feel like I''m playing ''Where''s Waldo''. lol I have read, and reread, I cannot find the scarf!

I can find a spoon though....

Very interesting Serg and Gary!

Gary, I will guess the top pear is the better?

Ellen here are the DiamCalc scores (some are only available in the Pro software).
the numbers are:
1. light return mono
2. ETAS for light return
3. ETAS for fire
4. ETAs for fire X DETAS
5. DETAS

These are not commonly used functions for cut grading - but you will be interested in the numbers. (bigger is likely to be better).

And here are the ETAS and DETAS images for those stones.
(if someone can put all images together in one post that would be great - I never learned how).

Now this is technology that is available and capable of being used for grading - especially the DETAS on the right.
DiamCalc does screen shots from stone scans and this is really valuable and useful - I have really only just started using it after a coaching session a month ago with Sergey.
Any Prosumers want to go there?
If you do then please download the free marquise Demo version and play with it.
http://www.octonus.com/oct/download/diam_demo_down.phtml

David and Dave this should answer your questions about grading vs developing new cuts etc and the relevance of this thread (which I want to aim at prosumers).

 

[Garry H (Cut Nut)]

Date: 7/30/2009 5:16:53 PM
Author: Garry H (Cut Nut)

Date: 7/30/2009 5:00:55 PM
Author: Garry H (Cut Nut)

Date: 7/30/2009 8:57:50 AM
Author: Ellen





Very interesting Serg and Gary!

Gary, I will guess the top pear is the better?

Ellen note the top pear has a distribution that is very strong thru the axis range but very weak from the sides - i.e. it will not pick up much light from the sides - so if you had a big window to the right and left and had the stone on a pendant - it would not get much happening. It would look great in one orientation only - and that is what the square carre (scarf) demo is all about.

Hope that helps

 

[Garry H (Cut Nut)]

FYI - here is the entire field - but only half of the studied stones in this optimization plan.
Sergey and Yuri have done this for cushions and the result yeilds a higher light return stone than a round brilliant.
We will shortly post videos of the stone we have had cut. So this is not just boffin stuff.
There are many other processes that involve a huge investment in time that led to the selection of these stones to be studied - and essentially what you see here is a rejection process in action

 

[Regular Guy]

David, to your two questions (or, make that 3 considering notes with your newest post), my bias is that it's about bias...

That is to say...

Date: 7/30/2009 4:43:37 PM
Author: Rockdiamond
Thanks Ira.
Do we agree that the title- implying that other methods are a 'last resort' is inaccurate?

The question I raised about picking- and how different experienced people looking at the same selection of stones with cut in mind will pick different ones- what's the feeling about that?

1) Please do see Serg's post, 3rd from the top, on the "bias" thread, page 14, here. His post motivated this thread, but since his comment had to do with the limits of reflector technology, and since you're there already, I did want to include you. I intended the audience to be two fold...represented primarily by you and Serg, and your positions. The use of the parentheses in the title was specifically intended to allow for the fork in the road. The "(any longer)" part, included in parentheses because it's optional, and did go to Serg's fork.

2) Bias is what I think makes for subjectivity. It's a best guess, born partly from reading here. I like to think that the possibility and actuality of cut grading is reasonable, because beauty is not highly variable, but largely predictable between people. I read that professionals get used to seeing things in a certain way, and may lose a naivete that has it's advantages. Alternately, of course, maybe the experienced view gains in subtlety and nuance, so that is sort of tough to say. But...I do like to think that overall, cut grading is more objective than subjective, that what I like has aspects to it that can be measured, and in this way, when a professional does their job on my behalf, looking for beauty, I can without too much concern understand that their pick would be my pick. Towards this...I have been lead to understand that issues with reflector technology (IS & ASET) are besides the point, that these tools, when used properly, merely help making the objective choice, and that if the reflector choice draws one away from what I would like... (brilliant, really, that Garry's most recent post is EXACTLY on this point) I would like to think that the mis-direction is either based on a mis-reading of the technology, or it is based on a bias in the perception otherwise.

3) With respect to low tech....technology can absolutely draw you in the wrong direction, and away from common sense. You know...in 3rd & 4th grade, they teach the kids to do estimation...because surely of this very thing. You need to trust (the technology, or whatever), and verify. But, I'll tell ya...I don't want a person who who simply has a confident sense of mechanics building a bridge for me. I instead want a skilled engineer, with a command of physics.

Without being experienced in viewing diamonds, unlike you, I am highly opinionated. My views are based in part on what I would like to think is correct...but also, what I find to be parsimoniously presented here, in ways I tend to find convincing. Evidence presented can lead to believability. On this board, there is a lot of data presented, providing many opportunities to cycle through and examine information in different ways.

I understand that the underpinnings of diamond beauty are based on physics, which allows cutters to repeatedly execute beauty. I think the cut of a diamond is highly correlated with beauty. I don't think these are subjective things, no. And, I think when technology works, it helps us find that beauty in ways we can trust and rely on.

The technology is coming forward, I'm sure, as is our understanding. That's what I think.

 

[strmrdr]

Date: 7/30/2009 5:22:54 PM
Author: Garry H (Cut Nut)
Ellen note the top pear has a distribution that is very strong thru the axis range but very weak from the sides - i.e. it will not pick up much light from the sides - so if you had a big window to the right and left and had the stone on a pendant - it would not get much happening. It would look great in one orientation only - and that is what the square carre (scarf) demo is all about.


Hope that helps

The light orientation is wrong for a pendant.
The first one actual picks up more light from the direction that the light will be coming from in a pendant.
That could outweigh any advantage of side lighting.
To get the actual pendant results you would have to tilt the dome or change the panorama.