Some interesting things from AGS class

[valeria101]

A couple of things about the fire chart seem counterintuitive: one... that there is no such thing as diamond with OK fire and low brilliance. There seem to be some, or then the look I have in mind may not be explained by the way this fire metric is modeled.

Otherwise, I wonder if the relation between fire and brilliance really is so strong then why bother measure them separately anyway?

I never took those pictures and overlaid them for real... But that funny idea and seeing them done so brings a question: it may be that technically there is no trade-off between the ability to generate fire and brilliance, but it doesn''t seem that these properties play out in the same conditions - which does, may be a matter of how strong and what sort of light source is there. Which probably sounds like a useless observation, but leads me to believe... that evaluating how fiery a cut is can be considered (sufficiently) equivalent with evaluating how good light return is in the light conditions that make fire show rather than white light return. Gibberish? Oh well...

 

[WinkHPD]

Date: 2/25/2006 10:41:53 AM
Author: valeria101


A couple of things about the fire chart seem counterintuitive: one... that there is no such thing as diamond with OK fire and low brilliance. There seem to be some, or then the look I have in mind may not be explained by the way this fire metric is modeled.


Otherwise, I wonder if the relation between fire and brilliance really is so strong then why bother measure them separately anyway?


I never took those pictures and overlaid them for real... But that funny idea and seeing them done so brings a question: it may be that technically there is no trade-off between the ability to generate fire and brilliance, but it doesn''t seem that these properties play out in the same conditions - which does, may be a matter of how strong and what sort of light source is there. Which probably sounds like a useless observation, but leads me to believe... that evaluating how fiery a cut is can be considered (sufficiently) equivalent with evaluating how good light return is in the light conditions that make fire show rather than white light return. Gibberish? Oh well...

Okay, another brilliant observation. We are getting into an area that I think I understand, but that I may not state completely correctly, that having been said, let me give it my best shot.

As per Peter''s gentle correction from last evening, the gray areas in the fire picture represent areas that are "unproductive areas. They are not areas that don''t have any dispersion. You can see that in the FireMap key where it says ''Obscured or low angle or leakage.''". In our subsequent phone call he explained that fire is best seen in direct light and that direct light is the key to beauty in a diamond. Direct light is described in the metric for the ASET as light above 45 degrees and up to either 65 or 75 degrees, depending on whether you are looking at the 40 blue or 30 blue metric. This is shown by red. So by his definition you would see the most dispersion where there is the most red. With the 40 blue metric there is more obscuration and thus less red. So, I am suspecting that you will not find areas of strong dispersion where there is not at least some red, but I am also suspecting that you will find areas of strong red, especially in the 30 blue, where there are NOT strong areas of fire. And, it is because of this that you will find the measurement of fire as part of the AGS grading scale.

My understanding is that yes, there are some very bright stones with very low dispersion, but no, there are not any dull stones with high dispersion.

Wink

P.S. I reserve the right to be corrected by those light scientists who actually know what they are talking about rather than thinking they suspect that it might be. Please understand I am a student, not a master. I believe the above to be correct based on my studies and conversations with some of those masters.

 

[RockDoc]

RE AGS Seminars


The classes in Vegas certainly sounded very interesting.

But I think the presentations scheduled for the AGS conclave at the latter part of April will be very substancial as well.

Marty Haske is going, I''m going, Bob from Whiteflash is going ( and they should send John too (hint), possibly Sergey will be there, as well as Udi from Sarin. Perhaps Rhino too. Hopefully Richard Sherwood will be there as well.

Peter and Jim will be there, and a load of other industry important people too, presenting a multitude of seminars on vastly different gemological subjects.

Hopefully the snags will be fixed by then and the new software made available as well.

Dave, I am curious as to why IMAGEM chooses not to consider what is an indudstry standard of separating and measuring Fire and Dispersion. In my experience, people really prefer the spectral color area of display as well as the intensity of the spectral colors, brilliance and scintillation. The Brilliance Scope does report this and measure it separately and on the live-report option the images for each are displayed in animation.

As for displaying FIRE, Marty has a way of making it visible as well. Once he has that in production, it will be significant additional to what is already out there. Perhaps the fellows at IMAGEM will consider supporting what the industry is considering a standard, and rather than departing from it.

Is IMAGEM going to have a way to see the results in actual real life mode? BScope accomplished this very dramtically with their viewer instrument, and I''ve had some very astute professional who are science smart folks, see this and remark about how great and informative this instrument is able to make HUMAN VISUAL comparisons obvious in showing the light return characteristics.

Additionally, Gemex ( B SCOPE) has now imaged 1 MILLION diamonds, and has some very significant data. The sheer amount of diamonds is certainly very important as it represents an extremely well sampled testing basis/foundation. Certainly a imaged sample of that many stones is and will be more significant to what many studies have concluded based on a far lesser quantity of sampling. Gemex''s software is constantly being upgraded and changed as well, and has been for quite a few years now.

Rockdoc

 

[WinkHPD]

I have had a couple of emails asking me what I am talking about with direct and indirect lighting and it occurs to me that I am discussing some fairly complex issues with the assumption that some of you actually know what I am talking about. The next several posts will be a short course on the ASET tool as taken with permission and attribution from the presentation given by Peter Yantzer at the AGS class I attended earlier this week. Since the Very Large Very Fine pictures that I posted at the very beginning of this thread each consist of 62,500 individual ASET renderings it might help to understand what the ASET tool does.

Angular Spectral Evaluation Tool.

Here is a quote as to what it is.

Wink

 

[WinkHPD]

For the purpose of this discussion there are three types of light.

 

[WinkHPD]

The red area is the one we want to maximize.

 

[WinkHPD]

And while the green area does contribute, normally we want to minimise this area.

 

[WinkHPD]

The blue area provides contrast which is very important as our brains are hard wired for it.

 

[WinkHPD]

Without some contrast, we might as well put small mirrors in our rings, then we could check to see if we need a shave or if our lipstick is on straight, but we could not have the excitement and scintillation that we so love about our diamonds...

 

[WinkHPD]

But although we need contrast, it must be a balanced contrast to add beauty and not detract from the diamond.

 

[WinkHPD]

Too much or too little will not do.

 

[WinkHPD]

When all the pieces come together correctly you get a beautiful stone with lots of red, a little green and a nice pattern of contrast for maximum brilliance, fire and scintillation.

 

[WinkHPD]

You can see here a great ASET picture next to a picture of a real diamond and compare the two for consistency.

 

[WinkHPD]

One more type of light needs to be considered and that is leakage, which by AGS is defined as places where the light is incapable of being reflected from that angle. This is light that is escaping the diamond, but not in a positive contribution to the beauty of the diamond. (Note, in some cuts, such as princess and Asscher cuts, some leakage can be a positive contrast providing consideration, while in round cuts we normally do not want leakage.)

 

[WinkHPD]

Here are a couple of examples of poor cutting, the fisheye and the nailhead.

 

[WinkHPD]

I hope that this short introduction to the ASET tool will give you a better idea of what you are seeing in the large pictures that I posted earlier. Thousands of very tiny ASET images next to one another, creating art from the cutting truths of the universe. But aside from being pretty they offer insites to where the beauty lies in the individual pictures, where we will get the best brilliance at 30 blue, and at 40 blue. (30 degrees of obscuration or 40 degrees.)

Maybe someday AGS will offer some of these as poster art, if they do I will be one of the first in line!

Wink

 

[strmrdr]

Date: 2/25/2006 4:14:00 PM
Author: Wink
And while the green area does contribute, normally we want to minimise this area.

I can name 2 very common lighting conditions/envirements where the primary lighting is low angle lighting.
How does this take that into account??

 

[strmrdr]

http://journal.pricescope.com/Articles/11/1/Hearts--Arrows-Diamonds---Its-not-all-about-light-return.aspx

symmetrical contrast adds to the perception of beauty.
Agreement 100% there.

 

[strmrdr]

leakage provides the strongest contrast and asschers take advantage of this to show sharply defined symmetrical patterns.
Leakage isnt always a bad thing.

 

[WinkHPD]

Date: 2/25/2006 4:49:53 PM
Author: strmrdr
leakage provides the strongest contrast and asschers take advantage of this to show sharply defined symmetrical patterns.
Leakage isnt always a bad thing.

Yes, that statement is made as pertaining to rounds. In princess cuts for example the leakage can provide great contrast to make the diamond more stunning, provided of course that it is in proper balance.

Wink

 

[strmrdr]

Date: 2/25/2006 4:54:56 PM
Author: Wink

Date: 2/25/2006 4:49:53 PM

Author: strmrdr

leakage provides the strongest contrast and asschers take advantage of this to show sharply defined symmetrical patterns.

Leakage isnt always a bad thing.

Yes, that statement is made as pertaining to rounds. In princess cuts for example the leakage can provide great contrast to make the diamond more stunning, provided of course that it is in proper balance.


Wink

Can you note that above please :}

 

[WinkHPD]

Date: 2/25/2006 4:44:45 PM
Author: strmrdr

Date: 2/25/2006 4:14:00 PM
Author: Wink
And while the green area does contribute, normally we want to minimise this area.

I can name 2 very common lighting conditions/envirements where the primary lighting is low angle lighting.
How does this take that into account??

You would have to tell me what you are referring to for me to give you a good answer. I know when I take my clients out into the hall to look at their diamonds we step into a dark corner with them facing into the corner and a well cut diamond still seems to gather light and sparkle while poorly cut diamonds really loose it in these conditions.

You may be asking the wrong student for a full answer but give me examples and I will forward them on to the cutting gurus on Mount Knowledge to see what they say...

Wink

 

[oldminer]

Dave, I am curious as to why IMAGEM chooses not to consider what is an indudstry standard of separating and measuring Fire and "Dispersion. In my experience, people really prefer the spectral color area of display as well as the intensity of the spectral colors, brilliance and scintillation. The Brilliance Scope does report this and measure it separately and on the live-report option the images for each are displayed in animation. "

The reason is that one uses the minimum number of variables that define the result one is lookiong for. The more variables one uses, the less accurate the result after a certain point. I think the explanation I have made details the nature of fir as a secondary attribute and the responses from others have done nothing to show otherwise. One can select an Ideal Cut without a measure of fire. One then selects a diamond they prefer from those ideal cuts, high, medium or low fire, if they even care. Fire is a neat marketing tool for branding, but it does not define the wide world of the Ideal Cut.


"As for displaying FIRE, Marty has a way of makig it visible as well. Once he has that in production, it will be significant additional to what is already out there. Perhaps the fellows at IMAGEM will consider supporting what the industry is considering a standard, and rather than departing from it.
Marty is an industry asset, but not a marketing guru, not sufficiently funded, and not widely accepted. He is known for his opinions and his knowledge, but he knows his approach has turned many people off. I listen to him with great respect, but cannot always follow his lead. Producing a finished piece of technology requires years of hard work to get it right BEFORE selling it. I sort of doubt Marty has the serious bucks backing what might otherwise be an excellent effort. As far as fire being now an industry standard, I differ totally. There are no industry standards on this subject. We are working on making them, but who is in charge of these "standards"? I predict there will be meetings in the coming years to create standards, but right now we are having it out in public. I think what we do have now is a "wish list" system. Standards are bound to follow when we find a worthy set of leaders. Discussion is good, but these desires are far from standards.

"Is IMAGEM going to have a way to see the results in actual real life mode? BScope accomplished this very dramtically with their viewer instrument, and I''ve had some very astute professional who are science smart folks, see this and remark about how great and informative this instrument is able to make HUMAN VISUAL comparisons obvious in showing the light return characteristics.
Imagem''s next effort will have some predictive methods for cutters of rough and will provide them a form of modelling. It would not be a big deal to feed the measured data into excellent 3D modelling, such as Sergey have given us with DiamCalc. I am encouraging such steps, but we have been busy perfecting and doing other tasks. The measures we take of light correspond to human perception data that has been gathered over a number of years of development. Models of this would correlate with what is going on in the prediictive world with the exception that so many variables exist in making predictions, the actual results may not agree. We prefer to measure actual results using very few variables. It is a proven methodology that trained scientists will not argue with. Gemologists may not see the importance of confining the number of variables because they are mostly far less educated in science. It is like arguing loudly with a deaf man. My father could not hear for his last 15 years and it was frustrating to hold a calm conversation. An argument was much more difficult to tolerate. It takes two to engage to make arguing worthwhile or productive. Right now, there are two camps on this subject. We will eventually all see the benefits of this debate.

"Additionally, Gemex ( B SCOPE) has now imaged 1 MILLION diamonds, and has some very significant data. The sheer amount of diamonds is certainly very important as it represents an extremely well sampled testing basis/foundation. Certainly a imaged sample of that many stones is and will be more significant to what many studies have concluded based on a far lesser quantity of sampling. Gemex''s software is constantly being upgraded and changed as well, and has been for quite a few years now."

B Scope has a large number of ex-users and detractors. It ha a small number of happy users, too. How many active customers do they have? What major lab is adopting their technology? Those statistics might be telling. It is a cool tool, but software upgrading won''t fix its basic, non-software related, internal problems. A million stones is a huge liability. I wish them all the best. We all like to support the equipment we have spent our hard earned money one. It is understandable. The number of diamonds tested is substantial, as you say, but an expert in statistics can tell you just as much with a far smaller sample. Large samples, like a million stones, is a false security. Why not ask an expert statistician at your local university how many stones would make a sufficiently large sample for what we measure? The answer will surprise you, I''d bet. It makes the huge sample size GIA used look pretty unscientific considering they employ what we believe are highly educated researchers. Its the fact that we don''t know much about technology, science or statistics that leaves us using our common sense and logic. While I have done the same for years, I have now gotten a better grasp on these subjects, and have learned that logic and common sense don''t always fit true scientific methodology.

I want to begin to convince people that they ought to look deeper into what is being held out to them by respected organizations before they make final decisions. Some of the smoke and mirrors are being cleared away from thed diamond business. We''ll see how it all ends up some time in the future.

 

[WinkHPD]

Date: 2/25/2006 4:57:20 PM
Author: strmrdr


Can you note that above please :}

Done.

 

[WinkHPD]

By the way, one of the things that most impressed me with the Octonus Diamocalc software was the real ASET pictures taken side by side with the predictive pictures. Bad symmetry made bad or not H&A images. It turns out with the accuracy of the non contact imaging devices that the images of the real stones and the predictive images were stunningly similar. That software REALLY works well.

Wink

 

[strmrdr]

condition one:

living room - typically lit by lamps around the perimeter at low levels.
Primary lighting indirect off the walls and secondary off the ceiling.

condition 2:
office envirement sitting at a desk with a desk lamp towards the back of the desk

condition 2a:
same place with window lighting.
Which is the condition im in right now.
4pm second story window about 4 feet from the window with light striking my finger from a low angle.

 

[strmrdr]

Date: 2/25/2006 5:07:13 PM
Author: Wink
By the way, one of the things that most impressed me with the Octonus Diamocalc software was the real ASET pictures taken side by side with the predictive pictures. Bad symmetry made bad or not H&A images. It turns out with the accuracy of the non contact imaging devices that the images of the real stones and the predictive images were stunningly similar. That software REALLY works well.


Wink

Iv noticed that myself in images taken under the aset.
With the condition that good data is fed into them which is why im rather leery of current sarin data specially with asschers.

 

[strmrdr]

Date: 2/25/2006 5:03:44 PM
Author: Wink

Date: 2/25/2006 4:57:20 PM

Author: strmrdr



Can you note that above please :}

Done.

Thank you.

 

[WinkHPD]

Date: 2/25/2006 5:08:30 PM
Author: strmrdr
condition one:

living room - typically lit by lamps around the perimeter at low levels.
Primary lighting indirect off the walls and secondary off the ceiling.

condition 2:
office envirement sitting at a desk with a desk lamp towards the back of the desk

condition 2a:
same place with window lighting.
Which is the condition im in right now.
4pm second story window about 4 feet from the window with light striking my finger from a low angle.

Storm,

I will hazzard a supposition here. In those conditions if you stood up, put your diamond perpendicular to the ceiling that it would not sparkle very much. (Image in my mind of man standing, putting hand flat on desk and looking down at diamond from above).

However, if you tilt your ring to look at it while you are seated then the light that you are catching will be above the diamond in relation to the table of the diamond, assuming that you have the light at your back when doing so. In that circumstance the light that is being reflected is in fact coming from "above" the diamond.

By the way, low light conditions are where diamonds like the EightStar and the White Flash New Line really shine and stand out.

Wink

 

[strmrdr]

interesting wink,
Desks are rarely put so the persons back is too the window too much glare and it defeats the advantage of the window office.
The desk is usualy at right angles to the window in 95% of the windowed offices im in daily working on computers.

Standing up actualy makes the condition worse in the living room.
Diamonds that draw low angle light would still have some life to them under those conditions.
The huge reflectors in an asscher would be even better.