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

[strmrdr]

One thing that many people don''t understand is you can see everything shown in an IS and ASET without the scopes.
The scopes just give you:
1: uniform lighting environment
2: it shows it all in one view
3: it is easier to see, understand and teach

 

[Ellen]

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

Thanks Gary. The funny thing is, before I read Serg''s post about the distributions of red and green, I wouldn''t have picked that one. I''m not saying his info is wrong, just that it got me off my normal train of thought...

 

[Ellen]

Date: 7/30/2009 6:00:14 PM
Author: strmrdr
One thing that many people don''t understand is you can see everything shown in an IS and ASET without the scopes.
The scopes just give you:
1: uniform lighting environment
2: it shows it all in one view
3: it is easier to see, understand and teach

Yes.

 

[Rockdiamond]

Date: 7/30/2009 5:35:52 PM
Author: 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.

Thanks for clarifying Ira!
The part I put in bold is where we disagree.
Beauty IS subjective, and always will be.
At the start of this thread I mentioned that it''s not necessary to use any high tech tools to learn if a diamond has a problem that might affect durability ( for example) or other inherent problems.
So, if we take chips cracks or other potential pitfalls away, then what we''re left with is how the thing looks.
Now, I''ve said beauty is subjective, but clearly there''s human experience, and what we all think a diamond is supposed to look like.
However the differences between a well cut stone doing badly on ASET, and one that does would both fall well within the "human experience" thinking of what a diamond is supposed to look like and delve deep into subjective territory.


Storm- I agree completely with your point about the use of ASET/IS- in fact, that''s an amazing point!

Let me acknowledge the weak point of using the most traditional methods, like mine.
The shopper is placed into a position where they need to "trust" someone else- the seller.
They may even trust the seller, but how can they verify it without tools like ASET/IS?

As I keep repeating, neither method is wrong, and both have drawbacks.

 

[Garry H (Cut Nut)]

The next level of rejection that was used in this pear shape study was when rays are always obstructed by an observer through a reasonable range of motion.

Sergey will probably do a much better explanation of this than i can.

as best I can:
The stone rocks thru a range and the blue from the ASET will always be present. (I like ASET leakage because i can easily see the leakage beside the blue which shows me the dark zone from 2 different causes).

 

[ChunkyCushionLover]

Date: 7/30/2009 1:24:28 PM
Author: 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

If you do end up buying a novo pease post pictures and the certificate stats I am very interested to know the depth of them.
The ones at mayors(birks in canada) were a lot more shallow(depth %) than the cushion HA stones listed at GOG and are all within 2% of each other.
I had a really snooty and suspicious Birks salesperson look through the certificates for me and grudgingly give me the information on them.

 

[Garry H (Cut Nut)]

Here is a close up of the ray paths

 

[ChunkyCushionLover]

Date: 7/30/2009 2:51:40 AM
Author: DiaGem

Date: 7/30/2009 2:36:30 AM
Author: ChunkyCushionLover

Date: 7/30/2009 12:15:34 AM
Author: lisa1.01fvs1
I like this thread as it has bearing on my situation a bit.

David, how would you go about asessing a patented cut fancy like Tiffany''s Novo (modified brilliant cushion)?

Garry in an earlier thread mentioned using an ASET scope to chose the best stone in specific reference to the Novo.

To quote you, ''For a consumer who has decided to take things into their own hands and decide outside a dealer''s advice- or even to re-enforce a dealer''s advice, it seems to make a lot of sense to use ASET/IS.''

Are reflectors valid for this type of stone and if so what would I be looking for? Or what should I avoid (too much green for example). (I think I''ll start my own thread on this and get more specific input.)

My instinct is telling me to go with my eyes on this one in different lighting environments if possible.

This is why Sergey''s and others'' research into the capabilities and limitations of reflectors are so intriguing to me at the moment.

The novo is close to a a square cushion hearts and arrows.
Stones like this one and others like it are cut to very exact standards and you won''t see too many like them http://www.goodoldgold.com/diamond/2106/ on this page you can see the IS. ASET and hearts viewer

If you are going into Tiffany''s to buy already set stones the best way is to use your eyes in different lighting conditions. (In a darker room, in front of the window, under the desk etc.)
Alternatively you can buy a handheld AGS ASET for $25 and go in there with it I bet they will be shocked!

.

If you did look through an ASET get good back lighting and from the side and then you would be looking for the contrast of blue arrows and red almost everywherelse. The more green or background colour you saw the more light leakage.
It takes some getting used to, you have to line up the girdle of the diamond paralell to the lense and in focus.

Are you sure the ''NOVO'' is a patented cut.
I believe there is prior art...

Sorry, no idea about the NOVO, the Amorique is patented it has 70 facets thought.

 

[Rockdiamond]

HI All,
The reason I suggested two different conversations was I don''t mean to ignore the part of discussion about the technical aspects of ASET/IS.
Say we stipulate the ASET/IS works exactly as advertised. We stipulate that these devices can measure light return, and light path with a great degree of accuracy.

I thought this was a discussion of advantages and drawbacks of different ways of selecting diamonds- and how Serg would select diamonds without the use of reflectors.

Again, I am glad for the opportunity to discuss this in a more neutral manner- I just don''t want to seem rude to the other parts that are more technically related to ASET/IS

 

[Regular Guy]

Date: 7/30/2009 7:34:53 PM
Author: Rockdiamond

I thought this was a discussion of advantages and drawbacks of different ways of selecting diamonds- and how Serg would select diamonds without the use of reflectors.

It''s not.

David, I''ll take part (at least) of the blame...both because I am frequently dense and unclear in my writing, and...because I did especially invite you here.

But...have you read yet the post, 3 down, on page 14 of the bias thread? I think if that doesn''t clarify, it would raise questions.

Please start there, and confirm you''ve read that before addressing this again.

See if it makes sense as to how selection is (or can be) like making spaghetti...

 

[Rockdiamond]

HI Ira,
Now I understand- I''m sorry it was me who was dense!

However, for me to take part in a conversation such as one where Serg details specific reasons he finds limitation about the use of ASET/IS, I''d need to be able to speak about details of using ASET/IS.
I''m not in a position to do so.


I am in no way desiring to knock reflector technology- however I can discuss practical aspects of how ASET/IS may impact diamond buying- and how different methods are useful, or less so.

 

[lisa1.01fvs1]

Date: 7/30/2009 6:46:06 PM
Author: ChunkyCushionLover

Date: 7/30/2009 1:24:28 PM
Author: 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

If you do end up buying a novo pease post pictures and the certificate stats I am very interested to know the depth of them.
The ones at mayors(birks in canada) were a lot more shallow(depth %) than the cushion HA stones listed at GOG and are all within 2% of each other.
I had a really snooty and suspicious Birks salesperson look through the certificates for me and grudgingly give me the information on them.

Hmm....perhaps T is trying to create greater spread with shallower cut if that''s the case. How this might influence optics is beyond me.

We''ll see. I''ll write down what I find when I go. There''s so much to mull over.

As to use of ASET for rejection - I''ll have to rummage through every Novo they have and then some to feel minorly satisfied.

Perhaps I should just keep my RB and leave it at that until I get a better grasp of the limitations of these tools. I say this b/c it''s easy to be overwhelmed by the "Wow Pretty" for almost everything in there.

The main issue here is that I have not evaluated many stones overall. This makes applying cut principals even more absurd to my untrained eye.

Less familiar stone cuts like the Novo make this task even harder.

 

[Rhino]

Garry & Serg ... great stuff.

I always find it amazing & interesting where each of our research takes us after we haven''t spoken for a time. ASET can be and is helpful IMO and were I a consumer wouldn''t want to walk into a decision without that data (particularly on fancies) but what many are clueless about is how it all translates to every day practical observation. What has always been of interest to me is the DiamCalc "darkzone" in particular and how much *that does* translate and correlate to practical observation and why I''m a big fan of the technology Serg has developed and continues to fine tune as well as your work too Garry.

The only potential danger IMO is if we place too heavy an emphasis on telling people to "use their eyes" or "trust" this or that person is ... does that person interpret "most beautiful" the same way I would? What is their standard for comparison etc.? It''s one reason I''ve been turning to the means I have been recently because it demonstrates both strengths and weakness'' of reflectors yet at the same time provides a standard by which to judge.

Ira, while your question wasn''t directed towards me in particular I''ll just chime in and add this.

While I am a strong advocate of reflector based technology, I''ll be the first to tell you they are not end-all, be all solutions even in way of cut quality. As Serg & Gary has pointed out a diamond can potentially have too much darkness even when the reflector image looks great due to dynamics that the controlled environment of a reflector doesn''t take into account. This is not to mention a battery of exams we perform that go outside the realm of cut and into clarity, color and issues that can impact diamond transparency and/or structural durability.

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

Right on man.

I''ve never liked "black" for ASET for examining leakage. It stinks and why I''ve always used white. Another thing ... our photographic setup for ASET ... the blues are 100% 75-90 obstruction with white being leakage. No confusion between the two in our photographic setup.

All the best,

 

[jet2ks]

I don't know about anyone else, but I am loving the technical aspects of this discussion. Some of it is still a little over my head (esp. some of the acronyms), but it is all interesting.

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

Sergey also mentioned that we have 2 eyes (stereo vision) the leakage from one view can be light return from another - this is imporant.

I know this was brought up by Serg in the other thread and is now a couple of pages old here, but I had a question about how this affects diamond viewing. Hope it doesn't sound too stupid.

Garry, Storm and Serg, you have all mentioned hard contrast, static black zones, whatever you want to call them. How does the stereo optic view change that and how do you factor in viewing distance when looking for these? As the viewing distance increases the variation of angles between the two eyes decreases. So as the diamond moves further away, one of these zones should be both easier to detect due to the angle becoming more acute, and harder due to the eyes having to focus on a relatively smaller spot. Do you have an optimal distance for checking for these leakage areas?

 

[Ellen]

Date: 7/31/2009 9:56:52 AM
Author: Rhino
Garry & Serg ... great stuff.

I always find it amazing & interesting where each of our research takes us after we haven''t spoken for a time. ASET can be and is helpful IMO and were I a consumer wouldn''t want to walk into a decision without that data (particularly on fancies) but what many are clueless about is how it all translates to every day practical observation. What has always been of interest to me is the DiamCalc ''darkzone'' in particular and how much *that does* translate and correlate to practical observation and why I''m a big fan of the technology Serg has developed and continues to fine tune as well as your work too Garry.

The only potential danger IMO is if we place too heavy an emphasis on telling people to ''use their eyes'' or ''trust'' this or that person is ... does that person interpret ''most beautiful'' the same way I would? What is their standard for comparison etc.? It''s one reason I''ve been turning to the means I have been recently because it demonstrates both strengths and weakness'' of reflectors yet at the same time provides a standard by which to judge.

Ira, while your question wasn''t directed towards me in particular I''ll just chime in and add this.

While I am a strong advocate of reflector based technology, I''ll be the first to tell you they are not end-all, be all solutions even in way of cut quality. As Serg & Gary has pointed out a diamond can potentially have too much darkness even when the reflector image looks great due to dynamics that the controlled environment of a reflector doesn''t take into account. This is not to mention a battery of exams we perform that go outside the realm of cut and into clarity, color and issues that can impact diamond transparency and/or structural durability.

Serg ...



Right on man.

I''ve never liked ''black'' for ASET for examining leakage. It stinks and why I''ve always used white. Another thing ... our photographic setup for ASET ... the blues are 100% 75-90 obstruction with white being leakage. No confusion between the two in our photographic setup.

All the best,

Great point.

 

[Rockdiamond]

I think everytone agrees "Trust me" coming from a seller about a diamond you might like or not sounds pretty slimy.
But in fact, trust is exactly what has to develop for a person to buy.
Both stores, and websites have had to find ways of earning trust- and communicating what they find beautiful and why.
Personally I have found that photos, video and personal observations work incredibly well.... and that ASET would arbitrarily "downgrade" stones I have picked based on visual attributes- which is why we don''t use it.


However, even an ASET/IS needs to be interpreted using....well, our eyes, right?
Plus, consumers who have not taken the time to learn , or simply have no interest in learning the fine points of an ASET still need to trust the vendor interpreting it for them.


Again, I''m not trying to make this into a knock against reflector technology- and Ira, it''s your thread- but I really would like to know what some of the others think of the points I''ve raised here

 

[elle_chris]

Date: 7/31/2009 11:58:11 AM
Author: Rockdiamond
I think everytone agrees ''Trust me'' coming from a seller about a diamond you might like or not sounds pretty slimy.
But in fact, trust is exactly what has to develop for a person to buy.
Both stores, and websites have had to find ways of earning trust- and communicating what they find beautiful and why.
Personally I have found that photos, video and personal observations work incredibly well.... and that ASET would arbitrarily ''downgrade'' stones I have picked based on visual attributes- which is why we don''t use it.


However, even an ASET/IS needs to be interpreted using....well, our eyes, right?
Plus, consumers who have not taken the time to learn , or simply have no interest in learning the fine points of an ASET still need to trust the vendor interpreting it for them.


Again, I''m not trying to make this into a knock against reflector technology- and Ira, it''s your thread- but I really would like to know what some of the others think of the points I''ve raised here

Why don''t you take an AGS0, H&A with a great ASET and or idealscope image, and make a video comparing it to a stone you picked with your own eyes that looks bad in reflector technology.
Show both stones side by side the way Rhino does in various ligtining conditions, and then we can discuss what we all see.

 

[Rockdiamond]

I did exactly that and we had an entire thread on it...let me find it.....

 

[Rockdiamond]

Here is the thread where I show two stones with ASET/IS

 

[elle_chris]

Date: 7/31/2009 12:16:05 PM
Author: Rockdiamond
I did exactly that and we had an entire thread on it...let me find it.....

Name of the thread?

 

[strmrdr]

Date: 7/31/2009 10:13:30 AM
Author: jet2ks
I don''t know about anyone else, but I am loving the technical aspects of this discussion. Some of it is still a little over my head (esp. some of the acronyms), but it is all interesting.

Date: 7/30/2009 9:15:13 AM

Author: Garry H (Cut Nut)


Sergey also mentioned that we have 2 eyes (stereo vision) the leakage from one view can be light return from another - this is imporant.

I know this was brought up by Serg in the other thread and is now a couple of pages old here, but I had a question about how this affects diamond viewing. Hope it doesn''t sound too stupid.


Garry, Storm and Serg, you have all mentioned hard contrast, static black zones, whatever you want to call them. How does the stereo optic view change that and how do you factor in viewing distance when looking for these? As the viewing distance increases the variation of angles between the two eyes decreases. So as the diamond moves further away, one of these zones should be both easier to detect due to the angle becoming more acute, and harder due to the eyes having to focus on a relatively smaller spot. Do you have an optimal distance for checking for these leakage areas?

To be clear darkness from leakage goes away with tilt only in most cases.
Darkness from obstruction goes away with distance and tilt.

I am actually working on a article about this with rounds.

This 34/40.5 combo which has potential issues has the same obstruction at 400mm as 34/41 does at 25mm

34/40.5 at 400mm

 

[strmrdr]

34/41 at 25mm

 

[strmrdr]

34/40.8 at 80mm has the same

 

[strmrdr]

34/41 at 400mm for comparison

 

[Rockdiamond]

Hi Storm,
It''s possible that there are people reading this who are not completely up to speed on the technicalities.
For example, the images you are posting.
These are not real diamonds, rather they are "virtual" diamonds, yes?

What is the point?

 

[strmrdr]

a good fic 35.5/40.5 at 265mm

This is the test at 400mm I use to see if the base combo needs to checked for contrast issues.
I found real world that such a diamond will stay dark looking under the table beyond 1/2 arm length.

With Asscher designs I want the contrast patterns to be visible at that range and design my contrast under them and check it for brightness at further distances under this DC lighting.
It is a trade off with the asscher design they will never be the brightest diamonds because of the kewl patterns.
Darkness under the table at extended range with rounds however bugs me and a lot of people, it isn't pretty.
It is said to have contrast issues.

 

[strmrdr]

jet2ks, there is more to it than that as tilt has to be taken into consideration also but it starts around the same point.

An interesting tidbit historically it was the 60/60 camp that came up with to much obstruction under the table as an issue.
They typically have deeper pavilions so its not an issue.

So one one side you have your obstruction under the table is bad HA on the other you had your leakage under the table is bad HA
The best diamonds from both camps neither is a real issue and the best cutters of both kept on cutting until the market decided to go away from 60/60.

 

[litebrite]

Garry H, I liked the bottom pear best even before seeing the numbers. Would this be because there is no bow tie but rather a crown shape where there are bowties in the others and there is more even distribution of red, blue, green in the image?

Storm, so the contrast patterns in asschers - this means that amongst the different patterns, that some are bound to reflect more light than others? I have always found the pattern in LaurenthePartier's asscher to be most pleasing and I think I like the wide step pattern best b/c there's a minimum of black contrast. Does the bright drop suffer from the 5 tilt angle problem? What about a really well cut bright drop? Also, thanks for the thoughts on hard vs soft contrast. Is that similar to dark black arrows on an H & A versus more silvery arrows?

Like a previous poster, I am having a hard time keeping up but find it a fascinating discussion. Forgive me if I don't have the correct lingo for my questions. I feel like I'm an undergrad high schooler in a graduate level class.

 

[Rockdiamond]

Well......I was invited in, but it''s gotten kind of ...one sided?

Thanks Ira- if you ever do want to discuss this, I''m very open to it!

 

[Serg]

Date: 7/30/2009 8:17:35 AM
Author: Garry H (Cut Nut)
Here you can see that unless there is a light dead ahead or your body is blocking lights from any illumination zones - the stone will not have the capacity to return any light from an entire suit of facets.

(this is what Sergey was referring to when he mentioned persistant DiamCalc dark zones in movies.)


We will be using video''s in tightly controlled lighting environements as an important part of our cut development work.


But this is not to say that IS, ASET and many other tools are not part of the methods employed.

Garry,
Sorry I need correct you post about Carre

French Carre example is about Blind zones in ETAS space( not about Black(dark) zones on diamond image)

See ETAS comparison between Carre and RBC( AGSO), I marked by color cycles ( color depends from size) most important Blind zones( where cut can not catch light from environment)
You can easy see what

1) Carre has big Blind zones in range 30-70 degree from table. this part of environment space is very important for small light sources
2) RBC has much more less quantity of Blind zones. size blind zones are much less and its appear mainly in range 60-90degree from table, this space is not important for spot lights( windows have bigger size than such blind zones)