To Sergey, all Cut Nuts, etc: A reply from ImaGem

[oldminer]

Here is the pertinent message to ImaGem from Sergey from an older thread. I think what ImaGem has replied in the body of this message will be of broad interest to forum readers and experts.

"Direct measurement of LIGHT from a diamond” is not the synonym of measurement without mistakes. BS and Imagem are direct measurement tools. Are results the same?Direct measurement is decreasing one type error and increasing other type error.• Operating characteristics of camera are far away from operating characteristics human eye.• Stereo vision• Very limited set of light condition • Start position of diamond
Dave; please send answer to my remarks. Several times I showed to you these problems but never received any answer from you or Imagem.Sergey Sivovolenko CEO OctoNus"

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxResponse to the above from ImaGem:

The scope of a methodology defines the types of problems for which it is appropriate and the inferences that can be drawn from it. Ray tracing methodology has proven valuable in modeling optical systems, especially systems in which optical material is homogeneous. Once designed, performance of optical systems is evaluated by direct measurement. In this regard, ray-tracing methodology is a predictive and a modeling tool and not a measuring tool. Improper use of ray tracing methodology is perhaps best illustrated by our experience with the Hubble telescope. Ray tracing methodology was used to design Hubble telescope. NASA built it under the strictest possible standards at a cost of over a billion dollars. But, in actual use in space, the system gave blurred images rather than crisp and clear images expected from the telescope. A very costly mistake indeed. If direct measurements had been taken under viewing conditions, this mistake could have been avoided. The error was extremely small, far less than the accuracy of all diamond measuring devices, but the effect was devastating to NASA.

We are now evaluating and discussing different systems to assess the appearance of a diamond through its light performance. It is anybody''s guess which system will have market acceptance. Nevertheless, we need to ask ourselves is a system capable of doing what it purports to do?

Asserting that a predictive modeling system is a measurement device, as some are saying, has no basis in science and does disservice to the industry. ImaGem measures light performance in a diamond directly. Methodologically, it is the right approach to claim that measurements are taken. The next question is do these direct measurements help us describe how viewers rate various diamonds? There is extensive body of scientific literature that explains how this can be done in general. Observational data are collected and statistical analysis is used to evaluate the efficacy of a set of direct measurements in discriminating between different classes.

This approach is taken by ImaGem to establish that our measures, (Brilliance, Sparkle, and Intensity) do indeed help us discriminate between diamonds whose appearance varies between Excellent to Commercial. ImaGem''s direct measurements also have strong basis in our understanding of human perception. The direct measurement approach developed by ImaGem takes in to account the body color, molecular structure, inclusions, as well as all subtleties in the way a diamond has been cut and polished. ImaGem''s direct measurement approach is also valid for different shapes, sizes and cuts of a diamond. While we must support a healthy debate on how best we can serve the consumer by informing him/her about the appearance of a diamond, we must also be wary of obfuscation.

We must be wary of fallacious arguments thinly veiled in a vain attempt to be scientific. ImaGem is open to anyone to send stones to AGA to independently evaluate the validity and effectiveness of the direct measurement approach developed by ImaGem to discriminate between various quality stones. In addition to round brilliants, ImaGem has developed light appearance grades for princess and marquise cuts and will work with others in the industry that wish to develop direct measurement for standard cuts or branded cuts. We are seeing increasing number of buyers and sellers accepting ImaGem''s approach because it is helping them make better buying and selling decisions. We believe that once the dust is settled, a direct measurement approach to light performance will become the industry standard.

ImaGem
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Sergey and all;

The invitation to send diamonds for testing an evaluation of the process is indeed open to anyone in the trade who is interested. The first diamond will be done for free and then further stones at a fixed rate for research reasons. Only the strength of your wallet limits the amount of testing you might wish to do.

You did ask if the BrillianceScope give the same results as ImaGem. It is my understanding that the answer should be “NO”. The results are not the same because there is something wrong with the Gemex approach. ImaGem believes they have the right methodology. I hope this provides a meaningful response.

I have often said that regardless of the number of parameters one throws into the pot, one could never calculate the weight of a diamond better than placing it on an accurate scale. Arguments made that adding more parameters to tighten up the results are “bad science” so I have been told several times by many different qualified people. I tend to think that there is a limit to how much and how well one may measure and then how well one can predict when compared to just a relatively simple direct measurement.

I think the the following paragraph below from ImaGem''s response is primary:

''While we must support a healthy debate on how best we can serve the consumer by informing him/her about the appearance of a diamond, we must also be wary of obfuscation. We must be wary of fallacious arguments thinly veiled in a vain attempt to be scientific."

xxxxxxxxxxxxxxxxxxxxx

Any thoughts?

 

[Serg]

Re: Ray tracing methodology was used to design Hubble telescope. NASA built it under the strictest possible standards at a cost of over a billion dollars. But, in actual use in space, the system gave blurred images rather than crisp and clear images expected from the telescope. A very costly mistake indeed. If direct measurements had been taken under viewing conditions, this mistake could have been avoided. The error was extremely small, far less than the accuracy of all diamond measuring devices, but the effect was devastating to NASA.

It is a very strange argument. How do you think was develop : COSTAR ( Corrective Optics Space Telescope Axial Replacement) for Hubble ?


''While we must support a healthy debate on how best we can serve the consumer by informing him/her about the appearance of a diamond, we must also be wary of obfuscation. We must be wary of fallacious arguments thinly veiled in a vain attempt to be scientific."



I sure we will send some stones to BS and Imagem, specially for test Fire and Scintillation

 

[oldminer]

"It is a very strange argument. How do you think was develop : COSTAR ( Corrective Optics Space Telescope Axial Replacement) for Hubble "

Eaxctly, Sergey, the argument is, "Why do it wrong the first time and have to do it over at huge expense?" Had the Hubble design been verified before liftoff, no remake would have been necessary. If you measure diamonds, calculate performance and just ASSUME that you are grading them correctly, you probably are going to make a myriad of different compunded mistakes. From time to time, calculatiuons will give proper results, but is that the goal? Are we saying "Close is close enough."

A better job can be done and that''s why we are discussing the issues.

 

[strmrdr]

funny hubble worked perfectly on earth when gravity was making the mirror sag.
It was never considered that low gravity would change the shape of the mirror.
It was not the numbers that were off it was garbage in garbage out.
No one considered the effect of gravity on a lens.

So if NASA can make that big a mistake isnt it logical that anyone can?
Thats why open standards and open methodology is the right way.
My biggest beef with imagem is that its just at this time a black box in a market overfilled with black boxes.
I could design a black box connect it to a computer and have it tell me what I want it to tell me too.
It doesnt tell anyone anything about the accuracy of the results.

Lets for the sake of argument say that it does everything it says it does there is a huge problem.
Diamonds are light dependant objects and there are several ways of cutting diamonds so they perform better in various types of lighting.
Which is better a diamond that shows a ton fire in candle light but is less bright in sunlight, or a diamond that throws a spot light like beam in direct sunlight that could start a fire but doesnt have much fire in candle light.
Those are very real trade offs when it comes to deciding what are the best specs to cut a diamond too.
Which is the best diamond?
Someone who spends a lot of time in candle light might say the first and someone who spends a lot of time in sunlight the second.
So how can a machine tell me one is better than another?
It cant.

The b-scope and ideal-scope can give us an idea how a diamond will act in direct light and the isee2, diamcalc simulations and actual photos can tell us about the diamond in indirect light.
Where does imagem fit in that picture?
Iv been asking that for a long time now.
What does it tell me about a diamond and under what conditions?
There is no way it can tell me how a diamond reacts under all conditions.
It just isnt going to happen with one lighting environment and one camera position.

 

[oldminer]

So if NASA can make that big a mistake isn''t it logical that anyone can?
It is illogical to knowingly use or recommend a method which scientists know leads to error. We all know people are not infallible. We see a mistake being made now, and want to bring it to the attention of those who can influence the final outcome.

It (ImaGem) doesn''t tell anyone anything about the accuracy of the results.
We say test it and see if you agree. ImaGem has spent a great deal of time in the testing and documentation of accuracy and repeatability of results. How it works is far less important that what it does. The same for a computer. I use them, but don''t understand what is inside the black box. I don''t need to understand, but I do need correct results.

Diamonds are light dependent objects and there are several ways of cutting diamonds so they perform better in various types of lighting.
You are right and that is why a scientist picks a "Normal lighting environment", one of the scientists own choosing, which creates an atmosphere where meaningful results can be obtained. This means that the results will make sense in the real world when the "Normal" is properly created and controlled. A "Normal light environment" is unlike everyday, regular lighting, but the results give eye-visible results that make human graders agree the "Normal" environment works. It is a bogus argument that says diamonds react differently in every different lighting environment and we have to take each of them into account. We will never, ever agree on a single environment. It requires a much more scientific approach and an end to this ridiculous red herring. Ray-tracing is just as dependent on an arbitrarily selected lighting environment and more inaccurate on end results. We need a solution to the issue of grading light behavior, not more arguments about what kind of lighting. Obviously, one can''t do this in the dark........Truthfully, I do not believe diamond cutters make diamond differently for different lighting. They basically use North Daylight and cut for that. A great diamond nearly always performs very well. I know of no diamond cut for unusual lighting high performance.....Do you?

I believe we can direct people to the best looking diamonds via ImaGem. It is still a matter of their own choosing which one to select. If they spend lots of time in candle light, then they can have a candle to make their decision. If they spend lots of time outdoors at noontime, then let them see the diamond outside at noon. It wouldn''t be BETTER to use ray-tracing to calculate this. It is better to look with your own eyes. However, with proper technology applied, we can select those diamonds which will be among the best looking diamonds when light is present in their environment. We are not taking people or the human eye out of the equation, but are giving accurate and consistent assistance in the quest for the best diamonds.

I have seen nothing in the Ideal-Scope that does not get confirmed by ImaGem. This simple tool and this complex set of tools compliment each other very well.

I don''t believe anyone is going to ever create a tool to tell you how a diamond will react under ALL possible conditions. What is important is having a tool that tells you how a diamond reacts in a scientifically "normal" environment which gives it a placement in the scheme of things. It can be judged to be among the best, or some grade further down. The human eye and the very smart dealer marketplace will set appropriate values, judge the success of this tool, and fine tune non- eye visible quality grades.

Lastly, the one camera, one position statement you made. I wonder how much you know or if this is something you are just throwing out to test the waters. I believe you''d be quite surprised to know what the right science can do with the right equipment and enough money. Maybe you do know, but the black box has not yet revealed all its secrets..... A little mystery is good for us!

 

[michaelgem]

Here is a post I made to a related previous thread, which is off the front page. We seem to have moved on from this point, but it bears posting, as the concepts are germane to this Imagem thread.


I agree with David''s well spoken ideas repeated here:
"My own comment is that modeling is very useful to cutters as it provides them choices and recipes for cutting and re-cutting diamonds to perform better. There is a huge need for cutters to learn about these changes and what to do with rough.

However, when it comes to GRADING diamonds, it just seems better are more reasonable to measure the actual performance than to estimate it through a huge process of measuring lengths, angles, facet ratios, etc.

My thoughts are that both methods, direct measurement and calculation of performance are highly useful tools, but for different parts of the trade. I don''t think it is logical to always calculate the light performance if one can measure it. It is very proper to calculate POTENTIAL light performance for instructing cutters on how to work rough or to recut diamonds. The end result should be measured, not calculated..........

I think my logic is way more solid than my ability to argue scientific details or technicalities with PHD''s and optical experts. I am just a guy with a deep interest in what is going on and have a degree of involvement in this ongoing process. Our industry will benefit the most from developing the best products. I have seen so many half-baked products come and go. This time, I sure would like to see our business make the best choices and use solid science, not smoke and mirrors." David S. Atlas

I add the following from my post to Bruce Harding:

"We believe most aspects of optical performance or diamond beauty may be more accurately observed, (or predicted), and evaluated from stationary images of a diamond , (face-up and tilted), under a representation of typical illumination and viewing circumstances." Michael D. Cowing

Re: Michael:
. Thanks for compliments.
. It sounds like your last paragraph, highlighted, is a quote from something. If so, what? Bruce L. Harding

This is my wording of the concept that I have been promoting for 6 plus years beginning in print in my 2000 Journal article and, among other ideas, elaborated upon in the 2005 Journal article: "Describing diamond beauty - assessing the optical performance of a diamond". A four page digest version, which you would better appreciate for its brevity, appears in the latest NY Diamonds Magazine and Israel Diamonds Magazine.

I have found a number of people that promote or are sympathetic to this idea or concept. I believe we can adequately handle the objections that have been posed concerning ''direct assessment'' from diamond imaging. For example, I have made the camera lens adequately ''see'' what my asymmetrically placed eye sees in typical illumination (including the diamond''s fire).

I like direct assessment from images of diamonds under a representation of typical viewing and illumination circumstances, because it can clear away for the consumer the mystery, smoke and mirrors, and allows for clear and easy-to-understand explanations of what constitutes the best, (or do I dare say Ideal?), diamond cutting.

Michael Cowing

 

[strmrdr]

Edit: rethought starting a fight over this.
Not worth it.

 

[michaelgem]

Hi strmrdr,

For someone who states "I’m not an expert on diamonds", your strong opinions seem to indicate you believe otherwise. That’s a good thing, as you stimulate all of our neurons, and God knows at my age, they need stimulating.

Re: “Dave are your telling us that a diamond graded highly by imagem machine will be a top performer is all light conditions? If you are I’m calling B.S.
The reason is simple cutting for top performance in one light condition will compromise another.
There is no diamond that will perform at the very top in every light condition.” Strmrdr

True. But it may still perform better on a comparative basis than other diamond cuts over the majority of typical lighting conditions. Your belief that cutting for top performance in one light condition will necessarily, (comparatively), compromise another is true and not so true and bears qualification.

For example, if we postulate that the Ideal cut is optimized for normal, face-up viewing in typical illumination circumstances, will its performance, although decreasing, necessarily be compromised compared to other cuts when both are tilted? The answer has been shown to be no. The Ideal cut maintains its superior beauty and performance under reasonable tilts.

The best or Ideal cuts (not referring to the AGS 0) may look best in the face-up, normal viewing position and decrease in performance as they are tilted. However, they will still be superior in performance to other cuts as they are similarly tilted in the majority of typical lighting conditions.

After all, that is how they came to be seen as Ideal, and why diamond connoisseurs and acknowledged diamond experts judge them that way.

Michael Cowing




....

 

[oldminer]

Michaelgem:

To add to your statements: If wished to construct a diamond that had high performance when tilted, the calculation method would be highly useful. Such a diamond would fail to be a tradional ideal cut becasue it would not perform well face up, bt would be charming when viewed at an angle....No one would care, probably.

Strmrdr:

Sorry I couldn''t get you to make your points. I was trying to see what you had to offer. Maybe I just have the right stuff after all.
I do appreciate a fair give and take.

 

[strmrdr]

Hi michaelgem,
Iv read your work awesome stuff.

After I posted that I thought better of it Dave is a good guy and I dont want to get into it with him.

I will address a couple things since its an honor that you replied.

Im not an expert on diamonds I am a student of diamonds.
Iv been lucky enough to have some awesome teachers but there are too many holes in my diamond education to consider myself an expert.
I have looked at all the diamonds I can get my hands on but until im in a situation where iv looked at several hundred and studied them in person I will be a student not an expert.


That said when I can back it up I do at times have very strong opinions.
I keep the experts around here on their toes just ask them!

Its great to see you posting here! Im looking forward to learning more from you.

 

[Garry H (Cut Nut)]

Thanks Dave,
I will add a few comments too

Date: 8/19/2005 12:07:04 PM
Author:oldminer

Asserting that a predictive modeling system is a measurement device, as some are saying, has no basis in science and does disservice to the industry. ImaGem measures light performance in a diamond directly. Methodologically, it is the right approach to claim that measurements are taken. It is the wrong approach for the industry and consumers because it will not allow creativity and innovation because any and all systems that do not enable the planning of new beautiful cuts hold back our industry. We are a bit like a car industry that has a choice of a T model ford - we need a GM system that offers differnet models and different choice of colors. The next question is do these direct measurements help us describe how viewers rate various diamonds? There is extensive body of scientific literature that explains how this can be done in general.There is no literature and no publications other than very limited info on Patents from ImaGem, Brilliancescope or ISee2. We would appreciate some publications that support direct mesasurement, and we woul especially like to read how this approach takes account of factors that humans observe, like this image below, that cameras and digital gizmo''s can not.

Observational data are collected and statistical analysis is used to evaluate the efficacy of a set of direct measurements in discriminating between different classes.

This approach is taken by ImaGem to establish that our measures, (Brilliance, Sparkle, and Intensity) do indeed help us discriminate between diamonds whose appearance varies between Excellent to Commercial. ImaGem''s direct measurements also have strong basis in our understanding of human perception. please prove this - it is critical The direct measurement approach developed by ImaGem takes in to account the body color, molecular structure, inclusions, as well as all subtleties in the way a diamond has been cut and polished. ImaGem''s direct measurement approach is also valid for different shapes, sizes and cuts of a diamond. Then why not grade them all equally - rate a princess and an emerald cut on the same scale as a round brilliant - it is the least we should do to be fair to consumers who are confused and can not make the comparison for themselves While we must support a healthy debate on how best we can serve the consumer by informing him/her about the appearance of a diamond, we must also be wary of obfuscation.

We must be wary of fallacious arguments thinly veiled in a vain attempt to be scientific. ImaGem is open to anyone to send stones to AGA to independently evaluate the validity and effectiveness of the direct measurement approach developed by ImaGem to discriminate between various quality stones. In addition to round brilliants, ImaGem has developed light appearance grades for princess and marquise cuts and will work with others in the industry that wish to develop direct measurement for standard cuts or branded cuts. We are seeing increasing number of buyers and sellers accepting ImaGem''s approach because it is helping them make better buying and selling decisions. Brilliancescope and iSee2 make the same claims, but as we the thinnly veiled scientific community think that these approaches are more about selling and less about buying. We believe that once the dust is settled, a direct measurement approach to light performance will become the industry standard. On behalf of the Cut Group, it is not our intention to disallow or stop any other grading system from being used, but what does concern us is that there are more and more systems that give a wide variance of grades for the same diamond. This leads to consumer confusion and will result in a shrinking of our industry because consumers will not trust diamond sellers. Things are getting worse, not better!!

ImaGem
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

 

[strmrdr]

In the interest of education:

Diamond 1:
Tune for direct light and white light return:

Cut for great optical and physical symmetry
Lets start out with a some what shallow/some what steep combo to maximize the size of the pavilion reflectors and keep the top thin to maximize the light return.
Lets say 34.4/40.9 that should do it.
57% table
Now lets go for a long LGF% to concentrate the light and drive white light return. Say 81%
lets open up the stars to let more light into those long reflectors.
55% sounds good.
We need some indirect light contrast so lets cut the girdle facets for contrast leaving a bit of light return behind but building a better balanced diamond. Sound familiar?

Diamond 2:
Tune for indirect light, low light, and fire

Cut for great optical and physical symmetry
Lets pick a good range of angles say 34.8/40.8
57% table
Now we want a lot of contrast and wide pavilion mains as well as to break up the light return into fire so lets set the LGF% at 75%
We want fire so lets go 50% on the stars.
We have enough contrast for indirect light in the arrows so lets cut the girdles facets for light return and paint them a little to increase light return and help balance the diamond a little. Gee wonder what diamond this is?


Diamond 3 lets cut us a FIC

Fire above all else
Cut for great optical and physical symmetry
55.6% table
depth 62.1%
35.8/40.6 combo sounds good.
Now the lgf% needs to be fairly long to drive the thick crown and low pavilion angle so lets go 79%
Lets go 45% on the stars we want that light broken up and we don't want the girdle facets too steep.
...............

All 3 of those would be great diamonds.

Looking at them in one lighting condition would not tell you that.

 

[oldminer]

All 3 of those would be great diamonds. Looking at them in one lighting condition would not tell you that.

The response is: Give one of each of these three hypothetical diamonds to me for a test probably all three would score EX+ or EX with ImaGem. I assume there would be are no hidden faults. It would be up to a consumer to differentiate which they prefer or up to a seller to advise which one would please them the most. The market would set the proper value. Making diamonds to display different sets of characteristics does not change their potential for beauty. Probably each one would be beautiful in normal daylight.... That''s my expert opinion.

 

[Serg]

re:It is illogical to knowingly use or recommend a method which scientists know leads to error. We all know people are not infallible. We see a mistake being made now, and want to bring it to the attention of those who can influence the final outcome.
Re:Improper use of ray tracing methodology is perhaps best illustrated by our experience with the Hubble telescope. Ray tracing methodology was used to design Hubble telescope. NASA built it under the strictest possible standards at a cost of over a billion dollars. But, in actual use in space, the system gave blurred images rather than crisp and clear images expected from the telescope. A very costly mistake indeed.


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


Why do you think It was science ( or raytracing) mistake?
“ .. It was realized that the 2.4 m diameter primary mirror suffered serious optical degradation due to a manufacturing error at Perkin-Elmer..”

Again your example with Hubble is very strange for me because I can not understand : Why is manufacturing error can prove what “direct” method is better than “Indirect” method?

Was really possible to check Hubble on earth?

Back to main discussion..

I see one of main advantage “Indirect” method Is ability to predict new unusual cuts and set of proportions. For example we can find best combination of crown and pavilion angle for Best Fire or Best LR, or best something other and then cut this diamond and check by Human observation. We can predict and do verification on unusual examples.

Direct method can not do it. Usually you should use diamonds in very limit range of proportion ( and specially cuts) for alignment direct system. It is reason why all direct system usually reject all unusual set of proportions. Of course BS, ISee2, Imagem are more sophisticate tools than Firescope and IdealScope, but they still be reject tools just.( please to consider this my statement like my hypothesis )

Next features could indicate problems of system:
1) Different metric for different cuts
2) Absence correlation of grade form size diamond. Is any direct system could show next correlation : Small diamond should has less number of facets than Big diamond?

 

[Serg]

5 years old post
--------------------------------------------------------------------------------
Dear all,

Let’s understand better the people knowledge and abilities behind the FireScope (FS), which is actually a specifically structured lighting conditions for a brilliant observation.

The FS makes the user ABLE to observe a specific image of a brilliant under the FS lighting conditions. Then the user gives the qualitative interpretation to the image in terms of 3D symmetry of a brilliant, light leakage via the pavilion and also judges on combination of the parameters like crown and pavilion angles.

The user could be also ABLE to compare the FS images of different stones and predict what stones will be similar or different in terms of Beauty (combination of Brilliancy, Fire and Scintillation) on the basis of similarity of the corresponding images.

However, there is no KNOWLEDGE about rules (i.e. models), which determine the Brilliance, Fire and Scintillation of the observed stone, therefore there is no way to predict which stone will be better in terms of these parameters. For example, low light leakage through the pavilion demonstrated by FireScope does not necessarily mean high Light Return and vice versa. (We define Light Return as the quantity of light, which comes to a man’s eye from the diamond). Moreover, high Light Return does not automatically mean good Brilliance, because the proper contrast should be in place as well.

KNOWLEDGE can predict an experiment result and explain the result. ABLE can not do so.

Richard’s digression into the weaponry history made us to think about fair analogue of the FireScope. In particular, we want to understand better the role of this tool within the Mankind historical attempt to identify the best brilliants.

Imagine yourself being a landlord of a reasonable area, which you want to exploit getting as much benefits as possible. In order to make the decision where to drill a water hole, for example, you would have two options: to invite a “rod-man” (an ancient way to search for water or hidden treasures) or to order a hydrogeological map of your area, which will accumulate the up-to-date expertise of scientists. Let’s consider every option in more details.

1. “Rod-man” option makes you absolutely dependent on the ABILITY of a “rod operator” to manage his tool and interpret the signals from it. It is easy to understand that in the combination “rod” and “operator” the contribution of each element to the final recommendation (where to drill) is dramatically up-weighted by the operator’s end. The contribution to the final recommendation regarding a stone within the combination “FireScope” and “operator”, from our perspective, is also heavily shifted to the operator’s end. Without any intend to belittle the level of operator’s expertise, we would stress that his/her recommendation will actually have uncertain level of confidence, because it is just a qualitative judgement. If, in order to increase the accuracy of judgement, you invited a second operator and got a different judgement, you are in a real trouble because you do not have any ground to understand, which one is more accurate.

2. “Hydrogeological map” option will give you the modern KNOWLEDGE about the general potential of your area in terms of not just water but minerals and, who knows!, diamonds as well. The figures, which make up a hydrogeological map like longitude, altitude, seam depth, etc. can be verified if you want and every new measurement will increase the accuracy of your knowledge!

Of course, the choice will also depend on the corresponding costs, but do not forget about the cost of the lost opportunity! So, the choice is strategic and it is your call. And who proved that the most beautiful stones have to have very high level of symmetry? And how do you plan do distinguish very high symmetry from very very high one?

If you prefer to think in terms of the history of sight development, we would share that the weapons with the most advanced spices of sights do not use now operators on-line at all, they are self-guided (did you hear about missile complexes like Patriot or Russian C-300?).
S,O,Y. http://www.gemology.ru "

 

[perry]

Strmrdr said:

funny hubble worked perfectly on earth when gravity was making the mirror sag.
It was never considered that low gravity would change the shape of the mirror.
It was not the numbers that were off it was garbage in garbage out.
No one considered the effect of gravity on a lens.


Not true. There was nothing wrong with the mirror, and it holds it shape correctly in both earh gravity and in space. The mirror was wonderfully designed and constructed.

The problem was in the assembly of the system (I don''t remember if it was the production testing assembly or the final assembly). The mirror had a specific focal length, as do all lenses and mirrors. The next optical component was assembled a couple of tenths of an inch from where it was susposed to be to match the mirrors focal length. Thus, modeling of the optical system showed it was perfect (all dimensions in the model were perfect). It was assembled incorrectly, and NASA cut the money to test the final assembly. Had they tested it the problem would have been obvious, and the fix very simple (I think it was only that a spacer was the wrong thickness).

The exact problem was determined when they carefully analyzed the dimensions of the production components to the final assemble components related to focal lenght of the primary mirror. By figuring out that the focal length was exactly "x" dimension off they were able to construct corrective optics. If they had not been able to determine how far off it was - they would never have been able to fix it.

The one good thing that came out of this. All space bound telecsopes are now final assembly optically tested before launch to verify optical performance, and repairs are made if any problems are found.

Thus, testing of a component is vastly supperior to modeling of it.

Perry

 

[Garry H (Cut Nut)]

We have not come far in 5 years

We now have AGS and GIA (and HCA) grading systems with very different results.
Who knows what Imagem, BS and ISee2 will prefer? But from hat we know about 2 of them, there is only partial agreement.

I wonder if i should get a new job?

 

[Serg]

re:There was nothing wrong with the mirror


see
http://www.stecf.org/observing/hstdocs/foc/handbook_v7.pdf


p.19

 

[strmrdr]

Date: 8/20/2005 8:44:48 AM
Author: perry
Strmrdr said:


funny hubble worked perfectly on earth when gravity was making the mirror sag.

It was never considered that low gravity would change the shape of the mirror.

It was not the numbers that were off it was garbage in garbage out.

No one considered the effect of gravity on a lens.




Not true. There was nothing wrong with the mirror, and it holds it shape correctly in both earh gravity and in space. The mirror was wonderfully designed and constructed.


The problem was in the assembly of the system (I don''t remember if it was the production testing assembly or the final assembly). The mirror had a specific focal length, as do all lenses and mirrors. The next optical component was assembled a couple of tenths of an inch from where it was susposed to be to match the mirrors focal length. Thus, modeling of the optical system showed it was perfect (all dimensions in the model were perfect). It was assembled incorrectly, and NASA cut the money to test the final assembly. Had they tested it the problem would have been obvious, and the fix very simple (I think it was only that a spacer was the wrong thickness).


The exact problem was determined when they carefully analyzed the dimensions of the production components to the final assemble components related to focal lenght of the primary mirror. By figuring out that the focal length was exactly ''x'' dimension off they were able to construct corrective optics. If they had not been able to determine how far off it was - they would never have been able to fix it.


The one good thing that came out of this. All space bound telecsopes are now final assembly optically tested before launch to verify optical performance, and repairs are made if any problems are found.


Thus, testing of a component is vastly supperior to modeling of it.


Perry

actualy we were both a bit off.
The gravity theory was one that was discussed at the time I didnt remember that it was found to be something else.
But the error was actualy in the direct measurement test equipment used in making the mirror.
Making the arguement even worse for the direct measurement camp.



http://www.uoguelph.ca/~ebaig/brian.html

The same information is available all over but that one is the easiest to understand.
Guess I should have checked.

 

[strmrdr]

Date: 8/20/2005 8:50:25 AM
Author: Garry H (Cut Nut)
We have not come far in 5 years

We now have AGS and GIA (and HCA) grading systems with very different results.

Who knows what Imagem, BS and ISee2 will prefer? But from hat we know about 2 of them, there is only partial agreement.


I wonder if i should get a new job?

The key to improving diamond cut is not with the cutters or the dealers its the consumers.
5 years ago how many consumers had Val''s , Belle''s, Mara''s , RG''s, and my knowledge of diamonds or even the chance to learn that much.
The only way the cutters will change is if the demand changes.
Your on the right path think 15 years down the road not 5.

 

[strmrdr]

Date: 8/20/2005 7:58:11 AM
Author: oldminer
All 3 of those would be great diamonds. Looking at them in one lighting condition would not tell you that.


The response is: Give one of each of these three hypothetical diamonds to me for a test probably all three would score EX+ or EX with ImaGem. I assume there would be are no hidden faults. It would be up to a consumer to differentiate which they prefer or up to a seller to advise which one would please them the most. The market would set the proper value. Making diamonds to display different sets of characteristics does not change their potential for beauty. Probably each one would be beautiful in normal daylight.... That''s my expert opinion.

Actually a system that didn’t differentiate between those diamonds is as useless as one that says they are bad.
The will display different personalities and it isn’t a stretch to say that that personality might be less than top end in some light conditions.
Which makes it imperative that we know the light conditions of the test.

Dave you believe in Imagem and want it accepted and that’s ok.
The reality is that its not going to be accepted as the end all of diamond cut grading.
Until we can tell where it fits in the order of things with the rest of the tools it is not even useful.
We can argue about it all month but thats the bottom line.

 

[Garry H (Cut Nut)]

1. I think you are being overly hard on Dave and ImaGem Storm. There is no reason it is less decisive or accurate than BS or ISee2 from what we know at this time, yet you will support data from those devices as part of a tool box.

2. Consumers will lead to every decreasing imposition of standards for the existing stsus quo. They will not encourage innovation because they have no way to tell a new cut invented today is great. Even the BS now makes it impossible to measure a new cut compared to an ideal round - and, if you believe. as the Cut Group does, that our system will lead to new and better cuts than the current round - then you will see that we need a cut grading system that can grade and be used to design.

 

[strmrdr]

Garry,
I have enough information on the B-scope to find it useful and it isn''t the end all of diamond cut grading.
Because its useful inspite of its short comings its on my tool chain of cut evaluation.

With imagem I don''t have enough info to do that.

isee2 i see as a curiosity more than a tool for the same reason.
Its interesting to study the diamonds it score highly and those it don''t.

No way would I buy a diamond based entirely on the isee2 or b-scope scores.

As far as which way should be used to design and test diamonds the proper answer is both but both have to be done in an open and scientific manner.
Right now the computer model and design group is doing a much better job of being open and scientific.
I support the cut group and I support direct observation technology its not an either/or situation.
But for me to support anything there has to be enough information that I can get a handle on it and properly apply it.
I have requested the information from imagem and been told its not coming so therefore I cant support it.

 

[perry]

Serg:

I can''t get your link to open.

Strmrdr: Your link identifying a small focal length error in the production testing of the mirror matches my posting above.

What you need to understand is that a telescope consists of more than just the mirror (or a lens). It is a series of optical components (mirrors and lenses) assembled to project an image onto either film or a detector plate (several possible detector plates can be rotated in). These optical components need to be precisely positiioned based on actual focal lenghts to work right together and project a clear image.

In actuallily it matters little if the focal lenght of any of the optical components is off a bit when they are being assembled, what is done is that their postition is normally adjusted during final assembly to account for that (which is how telescopes have been built for over 100 years). Moving the primary lens or mirror is common, adjusting the position of the "eyepiece" optical lens is also common (and depending on the design of the telescope there may be more mirrors and lenses that could be moved).

Initially, the Hubble telescope project had a budget line item for a final optical test of the entire telescope assembly to ensure it was all correct (and fixes could easily be made if needed). However, opticians had gotten really good at precisely controlling focal lenths and the engineers, under budget pressure, felt that with the modern tolerences - that performing the final optical test of the entire assembly was not needed given that the last several spy satilites - which used the same size mirror from the same company passed their final optical performance test with no problems.

So the problem was not that testing of the mirror curve failed. In fact testing indicated a problem, but people deferred to the wrong device. It was not that the focal lenght was off a bit (it used to be that focal length would only be in a range and final adjustement were made during telescope assembly), it was that the final optical test of the entire telescope assembly (all the mirrors and lenses) was not done to ensure that as an assembly that they were "right." The real fix is that every space telescope is now final optical tested to ensure that it really does work properely (the Hubble was the first, and last, space telescope to not have been tested as an assembly).

In the end, testing would have worked. Modeling would never have caught the problem.

In the end, what saved the Hubble was the fact that the incorrect primary mirror tester was still assembled and could be analyzed to determine how far off it was. Should it have not been intact - they probably could not have built the corrective optics for the Hubble. Interestingly, that "corrective optics" package allowes the positions of several of the lenses to be changed to fine tune the focal lenght as needed in case they were off a bit. I don''t know how much, if any adjustment was made when the corrective optics package was inserted into Hubble.

Perry

 

[Serg]

re:I can''t get your link to open.

Link work perfectly, but you need the Acrobat Reader to read this document

re:What you need to understand is that a telescope consists of more than just the mirror (or a lens). ... So the problem was not that testing of the mirror curve failed. ...

 

[Serg]

Dave,

Below are my next very important questions to Imagem:

What diamonds had been use for training Sophisticate Intelligent software and what diamonds had been use only for verification result of such training.?
Who and How did grade beauty, Scintillation, brilliancy of diamonds for training and verification?

Same questions I have for BS too.

Hardware, software could be closed for protection investment.
But information about collection diamonds for training and verification should be published.

I see only one reason for hiding such information - Had been used convenience sample of diamonds.

Could you show other reason?

 

[michaelgem]

There are two or more discussions entwined on this thread. This post is directed more toward Strmrdr thinking and his posts. Sergey''s comments and questions are more central to this thread and Imagem, and this post is not related to that discussion. Sergey''s points are important for all the cut grading players to consider and address.

For more than 6 years I have been saying that if you want to define a best or ideal cut you should first spell out with respect to what criteria your cut is ideal, and then you need to justify that claim.

Is it with respect to craftsmanship criteria such as perfection of polish, facet meet points, facet alignment, symmetry, facet angles and proportions? Before performance became the buzzword, most grading of diamond cut made judgments that fell within the craftsmanship category. A Bill Bray score of close to 1000 is an example, as is the old AGS 0 grading system.

Today and increasingly, the savvy consumer, like strmrdr, is looking for proof of the extent to which all the various factors of craftsmanship have or have not actually resulted in the most beautiful diamond in realistic illumination and viewing circumstances. This category of ''direct assessment'' of performance aspects of diamond beauty such as brilliance, fire and scintillation has gone mainstream with the GIA cut grade and the performance oriented changes to the AGS cut grade.

So is your cut ideal with respect to the performance attributes of diamond beauty- brilliance, fire, and sparkle? If so your customer may want to know in what way you are maximizing these attributes of diamond beauty. I doubt the savvy consumer will be satisfied with you measuring diamond performance and beauty up to a point and then saying beyond that it is a matter of taste.

I doubt there is much interest in a diamond said to be a fiery ideal and only good on brilliance, or one said to be a brilliant ideal that is so-so on fire.

I suspect to convince the consumer that their cut is best or ideal the jeweler will need to make the case that his diamond has the comparatively best combination of the three established performance attributes of beauty - brilliance, fire and sparkle. These attributes must be present in typical viewing and illumination circumstances, not just in the jewelry store. And the jeweler will need to back that case with clear and understandable evidence, not just numbers from an impressive piece of equipment.

I temper these beliefs with the acknowledgment that the savvy consumer being discussed is still a small although growing segment of the buying public most of who buy on emotion, price, brand identity or numbers from an impressive piece of equipment. Most of the large jewelry stores I know are too busy making money with the majority to bother going after this growing minority.

That is fine, because there are plenty of dedicated companies who are filling or moving to fill this small and growing market niche.

Michael D. Cowing

 

[strmrdr]

michaelgem,


You used a couple terms that have specific meaning here so im going to define a couple terms to avoid confusion.

fiery ideal cut = fic = highly sought after by some people that prefer very fiery diamonds. There have been people that spent 6 months here hunting down a good example of one.
brilliant ideal cut = bic = the vast majority of ideal cut diamonds on the market.
...

What is the biggest difference between an ACA, a cut by infinity, an 8* and a GOG classic diamond?
They all have different personalities and will look different in the same lighting and some people like the performance of one over the other.
Why?
Because the cutter/designer cutting them chose a specific set of compromises when cutting them.
No one diamond formula is the best in all light conditions.

Are all those considered top of the line diamonds?
Yea I think they are.

Using only one tool that looks at them under only one light condition you may dismiss one of them as not being as good as the rest.
Put them in another light environment and that diamond could very well be the best one in that test.

 

[Garry H (Cut Nut)]

Michael I agree with you and here is the view that is shared by those in our little enclave.

We are designing a beauty grading system. We think some labs will use this system to grade the potential beauty of diamonds. but we are not designing a Cut Quality system.

We expect individual labs will add their own personality to our ''beauty'' system by adding:

1. Polish Quality (our system will not meausre this initially)
2. Symmetry (We will offer scanners that are more accurate than any on the market, but many labs will prefer their facet point analysis)
3. Transperency grading
4. Durability / girdle thickness and other proportion based assessments (maybe including spread)

 

[michaelgem]

Re: You used a couple terms that have specific meaning here so im going to define a couple terms to avoid confusion. fiery ideal cut = fic brilliant ideal cut = bic
What is the biggest difference between an ACA, a cut by infinity, an 8* and a GOG classic diamond?
They all have different personalities and will look different in the same lighting and some people like the performance of one over the other.
Why?
Because the cutter/designer cutting them chose a specific set of compromises when cutting them.
No one diamond formula is the best in all light conditions.

Sorry if my comments were seen as stepping on Pricescope orthodoxy. I was not speaking of fic or bic, but of the lack of interest in diamonds that supposedly excel in one of the aspects of diamond beauty at the expense of another.

I am willing to bet that ACA, Infinity, 8* and GOG will make the case that they have not compromised any of the performance attributes of beauty - brilliance, fire or sparkle in cutting their diamonds. And it is in that sense that they could claim to be ideal or if that is no longer politically correct, best.

Michael Cowing