Light Return. Is maximization really the answer?

[oldminer]

I would say the answer is "No". When a viewer looks at a diamond, they want to see lots of sparkle, pattern and plenty of bright light coming back to their eye, but mixed with brightness are some areas of relative darkness which show the pattern and allow concentrations of light to be seen as scintillation. If you think about getting the maximum light back, you'd construct a plain mirror which would send nearly all the light back to your eye without the benefit of the desired pattern , sparkle and contrast elements. It would fail to be as beautiful or desirable. Very few people would seek such a bright, yet uninteresting looking diamond.

Are there experts or consumers who would want to maximize light return beyond today's Ideal Cut ranges if the trade off resulted in the direction of more light return yet less of the other important elements?

Do you think moderation near the top of light return, which is the way it is now, is the right way to describe what the best light performance range is? Or, are we incorrect? Should we seek bright light return faceting designs which give even greater amounts of light back knowing other elements must taper downwards to accomplish this?

What do you think? Do you disagree?

 

[Karl_K]

Dave

As Brian would say "visual balance" is where diamond beauty begins and ends.
Each type and subtype has a different balance unique to itself that makes it beautiful to different people.

To answer your question higher than an ideal cut RB brightness is possible with acceptable contrast.
The answer in doing so is phase based contrast.
Leakage and obstruction theory alone does not explain contrast in real diamonds they are only a part of it.
That is a very huge weakness of many cut grading systems.
Real world lighting is never symmetrical and diamonds are never static when worn.

 

[Demon]

Scintillation is the most important part, to me. (Which I was going to say in that thread the other day, but it got really technical very quickly) When I''ve watched video''s from Good Old Gold, I could just stay on the ''star sparkle'' part forever. So no, maximizing light return any more than it is now would not be a good thing, IMO.

 

[yssie]

There are many people who find 8*s beautiful and desirable. I'm not one of them: I find that a little leakage around the girdle of a round gives the stone liveliness and definition.


I imagine everyone would agree that the extremes - an overly leaky stone and a mirror - are undesirable to the vast majority of consumers, but I suspect there will be a tremendous amount of variation in what different individuals find appealing within that range.


I do prefer that a stone accepts and returns whatever light it is going to reflect and refract from the top (normal to the table) rather than from an angle to the crown or worse, from the pavilion. A princess with lots of red in the ASET is going to look whiter in a room with beige walls and a white ceiling than one with lots of green, as much of the light being returned by the second stone is entering after reflection off those walls, no matter how much blue and black/grey/white the images show (and as long as those areas of obstruction/leakage are well-balanced in quantity and symmetry I do believe they enhance the stone's appearance).

 

[kenny]

I'm no pro or expert, just a passionate consumer.
As I've mentioned we have 4 superbly-cut diamonds, an ACA, an Asscher, a Solasfera and an Octavia.

I agree that a flat mirror would provide max light return than a faceted diamond.
Clearly a balance of high light return and a pleasing pattern, scintillation, and contrast is desirable.

The Octavia provides the absolute ultimate optimization of these qualities of any cut I have seen.
It seems to have a battery in it; it can grab the faintest light and seem to amplify it.
Still it is far from a flat mirror since it has a dramatic and pleasing pattern.

That's all I had to add.
I can't define good cut, but I know it when I see it.

 

[Karl_K]

part 2 to my answer:
Higher than RB brightness should not be the design goal of every design reasonable brightness is however a must for a well designed diamond.
Getting the highest brightness should not comprimise the other aspects of diamond performance.
Yes it is possible to do that.
But there is a lot of unexplored potential out there.
Until Octavia who would have though that an asscher could be brighter or at least as bright as the best cut princess cuts on the market.
Could I make it brighter? yes slightly... will I... no,,, because its visual balance would be affected in a negative manner.

 

[zhuzhu]

If all I care about is light return then I will wear a piece of diamond-shape mirror.

 

[ChunkyCushionLover]

Date: 4/30/2010 4:33:40 PM
Author:oldminer
I would say the answer is 'No'. When a viewer looks at a diamond, they want to see lots of sparkle, pattern and plenty of bright light coming back to their eye, but mixed with brightness are some areas of relative darkness which show the pattern and allow concentrations of light to be seen as scintillation. If you think about getting the maximum light back, you'd construct a plain mirror which would send nearly all the light back to your eye without the benefit of the desired pattern , sparkle and contrast elements. It would fail to be as beautiful or desirable. Very few people would seek such a bright, yet uninteresting looking diamond.


Are there experts or consumers who would want to maximize light return beyond today's Ideal Cut ranges if the trade off resulted in the direction of more light return yet less of the other important elements?


Do you think moderation near the top of light return, which is the way it is now, is the right way to describe what the best light performance range is? Or, are we incorrect? Should we seek bright light return faceting designs which give even greater amounts of light back knowing other elements must taper downwards to accomplish this?

Really depends on your definition of maximization. If its an existing cut like an emerald cut or princess tweaking the angles for maximum intense light (gathering light from overhead) is very important and there is room for improvement in the cuts currently available. I'm not worried that these cuts will turn out that optimization will result in anything like headlights with no contrast, scintillation or fire. In this design there are always going to be virtual facets that are out of phase with each other and tweaking this will result in a more beautiful diamond.

In each fancy shapes choosing a cut or designing a cut that minnimizes weak light return and leakage is one goal, once again this theoretical all in phase virtual facets that look like a mirror or headlights is really not an issue I see that is of major concern. Maximization to me is a good balance of brightness, contrast, fire and scintillation and there is still a lot of room for better maximization and optimization in almost every fancy shape.

 

[Serg]

Date: 4/30/2010 4:33:40 PM
Author:oldminer
I would say the answer is ''No''. When a viewer looks at a diamond, they want to see lots of sparkle, pattern and plenty of bright light coming back to their eye, but mixed with brightness are some areas of relative darkness which show the pattern and allow concentrations of light to be seen as scintillation. If you think about getting the maximum light back, you''d construct a plain mirror which would send nearly all the light back to your eye without the benefit of the desired pattern , sparkle and contrast elements. It would fail to be as beautiful or desirable. Very few people would seek such a bright, yet uninteresting looking diamond.


Are there experts or consumers who would want to maximize light return beyond today''s Ideal Cut ranges if the trade off resulted in the direction of more light return yet less of the other important elements?


Do you think moderation near the top of light return, which is the way it is now, is the right way to describe what the best light performance range is? Or, are we incorrect? Should we seek bright light return faceting designs which give even greater amounts of light back knowing other elements must taper downwards to accomplish this?


What do you think? Do you disagree?

Dave,
there are several definitions for Light Return . It is depends to What zone of space you want return light and from what zone of space you can collect light
GIA return light to upper hemisphere(WLR) , others return light to one "point zone" for fixed or for several tilted diamond positions.
key point here is zone of space from which diamond could collect light when you calculate Light return. If diamond collects light from whole upper hemisphere ( even except head(ASET/IS) and may be body) then task to maximize Light return has not any sense. ( answer is any diamond with zero leakage . we know beautiful and ugly diamonds with low leakage, so maximization light return from whole hemisphere can not separate ugly diamonds from beautiful diamonds)

more correct task for Light return maximization when diamond collects light from small zones with random distribution .
"in other words we need maximize cut ability redirect light from single small light source with random position to consumer eyes " such Light return maximization is very important and helpful

 

[oldminer]

Serg;

I realize now that you have a far more complex view of things than most of us. You are right that one could want to design a diamond which distributed light better than another. It might be a very unusual diamond or may have some surprises in its appearance in certain lighting. However, my goal is to be able to measure Light Return in an agreed, Standard (normal) evironment. This would allow consistent results to be reported to any consumer from any lab using such technology. After we see how a sufficient number of stones measure, we can create an agreed grading scale which corresponds to human perception of the quality of how these diamonds look to our human eyes. Yes, it would only be in one standard lighting environment, but it would be a very useful addition to diamond grading.

 

[Andelain]

Date: 4/30/2010 5:16:37 PM
Author: yssie
There are many people who find 8*s beautiful and desirable. I''m not one of them: I find that a little leakage around the girdle of a round gives the stone liveliness and definition.


I imagine everyone would agree that the extremes - an overly leaky stone and a mirror - are undesirable to the vast majority of consumers, but I suspect there will be a tremendous amount of variation in what different individuals find appealing within that range.


I do prefer that a stone accepts and returns whatever light it is going to reflect and refract from the top (normal to the table) rather than from an angle to the crown or worse, from the pavilion. A princess with lots of red in the ASET is going to look whiter in a room with beige walls and a white ceiling than one with lots of green, as much of the light being returned by the second stone is entering after reflection off those walls, no matter how much blue and black/grey/white the images show (and as long as those areas of obstruction/leakage are well-balanced in quantity and symmetry I do believe they enhance the stone''s appearance).

This is an interesting topic and one that I''m going to have even more of an opinion on in a couple weeks. I have an Eightstar on my hand and think it''s absolutely the cat''s meow, plus I have a WF ACA on it''s way to me now. When it get''s here I''ll put the 2 side by side and compare. They''re not too far apart in color and size either, so I think it''s going to be interesting.

 

[Rockdiamond]

Great post David
of course I''ve been making this point for years here
in fact efforts at measuring light return completely miss the mark
it leads to the assumption that certain stones are "better" when they are simply different

 

[oldminer]

I do recognize that the measurement of Light Return can be a very useful tool in designing and marketing diamonds. Being able to increase light return would give a marketing person a lot of leverage to claim "More is better!" when it just might not be true. We know that with light return, a lot of light return is desired, but it is not the maximum, theoretically possible light return which works best for anything passing as an accepted design for a faceted diamond currently. There are other considerations in the appearance of a diamond which dictate light return levels which work the best.

The way the grading of cut for light performance has been done by AGS, GIA and ImaGem is by using sufficent samples of various stones and having panels of people put them in order of beauty and quality of appearance. There must be room for people who don''t think exactly like the statistical sample panels and who would prefer somewhat other looks in the diamond of their choice. This is what actually happens when you can select a diamond from an inventory of stones that are all in front of your own eyes. With the Internet shopper, the safest bet is going toward the best possible cut. In fact, this does limit your choice, but really, how can you go worng when it is guaranteed that a fine cut will produce wonderful results. If you do have an in store opportunity to shop[ and compare visually, you may well decide on a GIA VG or GD cut or if anyone had them I am dead certain many might love a less premium AGS1 or AGS2 cut stone. Buying one of these sight unseen would be a lot riskier and that is part of the reason for our continuing debates on Pricescope.

Consumers who read all of this will learn how to do the best job of buying no matter if they shop only on-line or mix their Internet knowledge with shopping in person.

I do wonder sometimes if the issue of painting and digging really means anything if an actual measurement of light return can be determined. Can a diamond with these cutting features actually be designed to be a top performing diamond without any harm to durability or size? My gut feeling is that Karl could design such a stone, but is there a deeper issue with painting and digging which has an ill effect on quality?

 

[Karl_K]

Dave,

No cut grading system takes every aspect of diamond performance into consideration.
This is something that Paul has been talking about lately.
Now he feels his particular visual balance is the best.
Brian feels his idea of visual balance is the best but it is different than Paul''s.
My favorites are different from both of them.

Who is right?
The answer is all and none of us because it will vary person to person.
It is in the eye of the its eventual owner to decide.

That said each of our ideas of visual balance will appeal to a wide range of people but some will like one better than the other.
No current technology shows all those differences.
When designing a diamond I have to take all of them into account.
Today a lot of that is TLR or that looks right when designing a visual balance for a design.
Brian and Paul did that before me in setting the standards for their diamonds.
The more things change the more they stay the same :}

Will the day come when all of it is graded?
No, because it will vary person to person and even groups of people.
This is a flaw in GIA''s study, to work well it has to be a random sample of diamond tastes, the problem? How to do that.
The first step would be to exclude anyone from the trade because they have strong preconceived ideas of what a diamond should looks like which is the last thing you want in a random sample.

This is not as easy as maximizing light return and never has been and never will be.

You asked if it is possible to mimic a visual balance with a totally different and strange combination using painting and digging.
The answer is yes and no and yes in only some aspects of performance.
At a glance yes in some lighting but deep study and some lighting will show differences.
If you only count brightness then it is no problem to do but understanding real diamond performance is only starting with the study of brightness.

 

[Diamond Explorer]

Date: 4/30/2010 5:17:01 PM
Author: kenny
... I can't define good cut, but I know it when I see it.

Kenny I think I go along with this school of thought, even though I could be considered a "pro".

I believe every diamond has to be judged on its own merits, and there is no one best diamond cut. There are a few different cuts that were mentioned that are simply in a different league in terms of their optical optimization. Among these, it would be nearly impossible to determine ones superiority over another, only personal preference.

While balance is quite an admirable quality, some people might prefer a diamond with performance weighted more to one property or another. A diamond is like a lover, and it is often it's personal eccentricities that make it special and beautiful to the beholder.

 

[Serg]

Date: 5/1/2010 6:34:03 PM
Author: oldminer
I do recognize that the measurement of Light Return can be a very useful tool in designing and marketing diamonds. Being able to increase light return would give a marketing person a lot of leverage to claim 'More is better!' when it just might not be true. We know that with light return, a lot of light return is desired, but it is not the maximum, theoretically possible light return which works best for anything passing as an accepted design for a faceted diamond currently. There are other considerations in the appearance of a diamond which dictate light return levels which work the best.


The way the grading of cut for light performance has been done by AGS, GIA and ImaGem is by using sufficent samples of various stones and having panels of people put them in order of beauty and quality of appearance. There must be room for people who don't think exactly like the statistical sample panels and who would prefer somewhat other looks in the diamond of their choice. This is what actually happens when you can select a diamond from an inventory of stones that are all in front of your own eyes. With the Internet shopper, the safest bet is going toward the best possible cut. In fact, this does limit your choice, but really, how can you go worng when it is guaranteed that a fine cut will produce wonderful results. If you do have an in store opportunity to shop[ and compare visually, you may well decide on a GIA VG or GD cut or if anyone had them I am dead certain many might love a less premium AGS1 or AGS2 cut stone. Buying one of these sight unseen would be a lot riskier and that is part of the reason for our continuing debates on Pricescope.


Consumers who read all of this will learn how to do the best job of buying no matter if they shop only on-line or mix their Internet knowledge with shopping in person.


I do wonder sometimes if the issue of painting and digging really means anything if an actual measurement of light return can be determined. Can a diamond with these cutting features actually be designed to be a top performing diamond without any harm to durability or size? My gut feeling is that Karl could design such a stone, but is there a deeper issue with painting and digging which has an ill effect on quality?

Dave,

re:I do recognize that the measurement of Light Return can be a very useful tool in designing and marketing diamonds. Being able to increase light return would give a marketing person a lot of leverage to claim "More is better!" when it just might not be true. We know that with light return, a lot of light return is desired, but it is not the maximum, theoretically possible light return which works best for anything passing as an accepted design for a faceted diamond currently. There are other considerations in the appearance of a diamond which dictate light return levels which work the best.

Sorry, but current Cut designing process is much more Multiform and Smart than Flat LR optimization .
see for example short description for my method:
1) First of all you need good Idea about pattern, girdle shape,..( it is very big issue ) and you need convert it into parametrical 3D model
2) on first level optimization we use several number rejection and selection type metrics as LR, DarkZone, ETAS FIRE, DEtas( for crown and table, for FaceUp and tilted positions). see table for example. LR is not one and not most important metric even during this stage optimization

3) when we found 3-10 interesting options, we create movies for different Light conditions to compare cuts during virtual Poll. During such comparison we consider optical Phenomenons( what can not be grade by modern metrics and which are part of Taste ) . if we found some new interesting positive optical Phenomenon ( for example special dynamical interaction between big and small virtual facets Or Fire pattern ) we try improve it during second optimization stage, in same stage we try reduce negative optical Phenomena ( for example bad contrast for Fire pattern )
4) then we cut winners and do comparison for real diamonds in different light conditions . in this stage very useful movies from motorized LightBox when you can separately count big and small Flashes step by step for each diamond in exactly same light conditions ( what include diamond position) and ask opinion from any number observers.

then you have new idea and can repeat whole cycle .

 

[Serg]

High Light return against High Detas and Fire

 

[oldminer]

Serg;

I am agreeing with you! My comments we meant to say there are marketers, sellers and cutters who would mis-use the concept of "More is better!". While it may be a good ploy for marketing, it is not a true situation, as you and others have shown or stated. Obviously, your far more complex strategy is one which is becoming better understood and is being adopted by cutters. It is a lot more difficult to explain it to a consumer, but there is no doubt about your approach being correct to design innovative and beautiful diamonds with pleasing light return characteristics.

The high road here is a complex amount of information. The easy, incorrect approach, is very tempting to follow, but ends up not being valid.

 

[Serg]

Date: 5/2/2010 1:35:59 PM
Author: oldminer
Serg;


I am agreeing with you! My comments we meant to say there are marketers, sellers and cutters who would mis-use the concept of 'More is better!'. While it may be a good ploy for marketing, it is not a true situation, as you and others have shown or stated. Obviously, your far more complex strategy is one which is becoming better understood and is being adopted by cutters. It is a lot more difficult to explain it to a consumer, but there is no doubt about your approach being correct to design innovative and beautiful diamonds with pleasing light return characteristics.


The high road here is a complex amount of information. The easy, incorrect approach, is very tempting to follow, but ends up not being valid.

Dave,
I am not argue with you too. I am agree with you on 70-80%.

re:It is a lot more difficult to explain it to a consumer,
yes , explanation it to a consumer and LABs is Huge problem. it is very hard task. this task is more difficult than to find correct metric for Fire.

But may be we do not need explain it? May be we need just Proof what it works?

 

[Karl_K]

Date: 5/2/2010 1:35:59 PM
Author: oldminer
Serg;


I am agreeing with you! My comments we meant to say there are marketers, sellers and cutters who would mis-use the concept of ''More is better!''. While it may be a good ploy for marketing, it is not a true situation, as you and others have shown or stated. Obviously, your far more complex strategy is one which is becoming better understood and is being adopted by cutters. It is a lot more difficult to explain it to a consumer, but there is no doubt about your approach being correct to design innovative and beautiful diamonds with pleasing light return characteristics.


The high road here is a complex amount of information. The easy, incorrect approach, is very tempting to follow, but ends up not being valid.

We live in a sound bite society where more/better/best sells.
That is a sad fact a so-so product with good marketing will outsell the best product with so-so marketing 1000000 to 1.

I had this very conversation with a PS famous personality, if he could not tell me the advantage of his product in 2 sentences then his company was in trouble.

 

[ChunkyCushionLover]

Date: 5/2/2010 1:35:59 PM
Author: oldminer
Serg;

I am agreeing with you! My comments we meant to say there are marketers, sellers and cutters who would mis-use the concept of 'More is better!'. While it may be a good ploy for marketing, it is not a true situation, as you and others have shown or stated. Obviously, your far more complex strategy is one which is becoming better understood and is being adopted by cutters. It is a lot more difficult to explain it to a consumer, but there is no doubt about your approach being correct to design innovative and beautiful diamonds with pleasing light return characteristics.

The high road here is a complex amount of information. The easy, incorrect approach, is very tempting to follow, but ends up not being valid.

Diamond design is about tradeoffs. More fire at the significant expense of brilliance will never receive widespread support or preference. Fire is only noticeable in some lighting conditions, brilliance can be seen in all of them. Extra and optimal brightness at the widespread absence of fire and scintillation would also never receive support or preference.

In perfect theoretical design space diamond performance criteria can be optimized and tweaked with preference given to one or the other.
This is in the theoretical diamond design world, in the real world we don't have the luxury of making such precise tradeoffs.
Most of the time the tradeoff is price versus appearance or even more common brilliance verus weight retention.
Different does not make two diamonds equallly beautiful, appropriate and equal tradeoffs and different designs might depending on the viewer.
Serg's example is what I would call different designs, most of the time I just see customer choices based on one being inferior to another in all but price or spread.

I hate opinions of tradesmemembers that try to equate different with inferior. There are often tradeoffs where you get less brilliance and gain NOTHING.

 

[Garry H (Cut Nut)]

Date: 4/30/2010 5:16:37 PM
Author: yssie
There are many people who find 8*s beautiful and desirable. I''m not one of them: I find that a little leakage around the girdle of a round gives the stone liveliness and definition.

Yssie this is very old now - but it might help others know what you mean.
(Great topic Dave)
http://www.ideal-scope.com/newsletters_issue004.asp

 

[ChunkyCushionLover]

Date: 5/2/2010 7:53:32 PM
Author: Garry H (Cut Nut)

Date: 4/30/2010 5:16:37 PM
Author: yssie
There are many people who find 8*s beautiful and desirable. I'm not one of them: I find that a little leakage around the girdle of a round gives the stone liveliness and definition.

Yssie this is very old now - but it might help others know what you mean.
(Great topic Dave)
http://www.ideal-scope.com/newsletters_issue004.asp

Not sure what you were linking to in that page. But here is Hearts of Fire Versus Eightstar IS images showing the almost all red IS for eighstar versus an "ideal" HA round.
How many people have ever seen same sized BGD HA versus WF ACA or Infinity HA or GOG HA versus Eightstar in different lighting conditions? I haven't but I suspect in all but price the differences would be extremely small yet the hyped differences seem to be so much larger on this board in favour of the PS vendors and according to Eightstar in favour of theirs.

 

[Serg]

Date: 5/2/2010 7:27:48 PM
Author: ChunkyCushionLover

Date: 5/2/2010 1:35:59 PM

Author: oldminer

Serg;


I am agreeing with you! My comments we meant to say there are marketers, sellers and cutters who would mis-use the concept of 'More is better!'. While it may be a good ploy for marketing, it is not a true situation, as you and others have shown or stated. Obviously, your far more complex strategy is one which is becoming better understood and is being adopted by cutters. It is a lot more difficult to explain it to a consumer, but there is no doubt about your approach being correct to design innovative and beautiful diamonds with pleasing light return characteristics.


The high road here is a complex amount of information. The easy, incorrect approach, is very tempting to follow, but ends up not being valid.

Diamond design is about tradeoffs. More fire at the significant expense of brilliance will never receive widespread support or preference. Fire is only noticeable in some lighting conditions, brilliance can be seen in all of them. Extra and optimal brightness at the widespread absence of fire and scintillation would also never receive support or preference.


In perfect theoretical design space diamond performance criteria can be optimized and tweaked with preference given to one or the other.

This is in the theoretical diamond design world, in the real world we don't have the luxury of making such precise tradeoffs.

Most of the time the tradeoff is price versus appearance or even more common brilliance verus weight retention.

Different does not make two diamonds equallly beautiful, appropriate and equal tradeoffs and different designs might depending on the viewer.

Serg's example is what I would call different designs, most of the time I just see customer choices based on one being inferior to another in all but price or spread.


I hate opinions of tradesmemembers that try to equate different with inferior. There are often tradeoffs where you get less brilliance and gain NOTHING.

reiamond design is about tradeoffs.

"

The Fall

When new quartz technology was developed by Swiss Firms (notably Girard-Perregaux[citation needed]) and offered to the industry, most Swiss manufacturers refused to embrace the technology. Others, outside of Switzerland, however, saw the advantage and further developed the nascent technology.[1]
The first mass-produced quartz watches with analog display and integrated circuitry were introduced in 1970. By 1978 quartz watches overtook mechanical watches in popularity, plunging the Swiss watch industry into crisis. This period of time was marked by a lack of innovation in Switzerland at the same time that the watch making industries of other nations were taking full advantage of emerging technologies, specifically, quartz watch technology, hence the term Quartz Crisis.
Ironically, the very technology which caused so much of the turmoil in the Swiss watch industry was pioneered by Swiss firms but rejected by the more conservative and tradition oriented watch industry. As a result of the economic turmoil that ensued, many once profitable and famous Swiss watch houses became insolvent and/or disappeared. The period of time completely upset the Swiss watch industry both economically and psychologically.[2]
The Swiss lost market share to the less expensive quartz watches produced mainly in Asia. During the 1970s and early 1980s, technological upheavals i.e. the appearance of the quartz technology, and an otherwise difficult economic situation resulted in a reduction in the size of the Swiss watch industry. The number of employees fell from some 90,000 in 1970 to a little over 30,000 by 1984, while the number of companies decreased from about 1,600 in 1970 to about 600.[3] However, as currently re-established the Swiss watch industry is vastly improved, producing watches in the higher ranges, mostly mechanical watches.
[edit]Factors leading to the Fall
Several factors combined to slow down the development of technology and production in Switzerland despite the fact that Swiss companies were at the forefront of the technology..[4]
[edit]a lack of conviction on the part of the industry leadership
The chief factors were a lack of conviction on the part of the industry leadership for either the need for or the possibility of the coexistence of electronic and mechanical watches, by the same brands,[5] in the same markets..[6]
[edit]the loss of the control of the mass production of watches with broad market diffusion
Another factor was the loss of the control of the mass production of watches with broad market diffusion.[6]
The years of comfortable revenues from the well protected monopoly from 1938 to 1952[7] cost the industry what had formerly been its most invaluable asset – its innovativeness. A handful of watch makers were disposed to make some copies of the quartz prototypes—history proves that they were capable—but they were not ready to launch into series production[8] until the Swatch watches in 1983
[edit]the renaissance & the Swatch
By 1981, the crisis reached a critical point. In 1982, the first Swatch prototypes were launched. The Swatch would be instrumental in reviving the Swiss watch industry. Hayek, merged SSIH and ASUAG, a holding company that controlled manufacturers of movement blanks, assortments and electronic components for the entire Swiss watch industry, and gave a new bill of health to all brands concerned and gave rise to what would become the Swatch Group.
[edit]Psychological Impact
Notwithstanding that the Quartz Crisis completely upset the Swiss watch industry both economically and psychologically, as currently re-established the Swiss watch industry is vastly improved, producing watches in the higher ranges, mostly mechanicals.


http://en.wikipedia.org/wiki/Quartz_crisis

"

"The Swatch Group today
The Swatch Group Ltd. is the number one manufacturer of finished watches in the world. The Group is active in the manufacture of finished watches, jewelry, and watch movements and components. It produces nearly all of the components necessary to manufacture the watches sold under its 19 watch brands and the multi-brand Tourbillon retail label, as well as the entire Swiss watchmaking industry. In addition, it operates its own worldwide network of distribution organizations. The Swatch Group is also a key player in the electronic systems sector.

The Swatch Group takes its name from the extraordinarily successful story of Swatch, one of the world’s most widely recognized consumer brand names. Less than 30 years ago, the Swiss watchmaking industry was battling a serious crisis; the first Swatch watches were released in 1983. The years since then have seen the recovery of the Swiss watchmaking industry as a whole, and the establishment of The Swatch Group as a strong, diversified industrial holding. This solid foundation has allowed the Group to broaden its reach and extend its range of brands. Today, the Swatch Group offers watches in all price categories, and Swatch Group monobrands and the multibrand Tourbillon retail mark hold leadership positions in all market segments:
– Breguet, Blancpain, Glashütte-Original, Léon Hatot, Jaquet-Droz, Omega and soon Tiffany & Co. in the Prestige and Luxury range;
– Longines, Rado and Union Glashütte in the high range;
– Tissot, ck Calvin Klein, Certina, Mido, Hamilton and Balmain in the middle range;
– Swatch and Flik Flak in the basic range segment;
– Endura in the private-label segment;
– Tourbillon, the retail mark under which all selected Swatch Group watch and jewelry brands of the Prestige and Luxury range, as well as Swatch products are offered in a unique and exclusive multi-brand environment.

Today, the Swatch Group continues to invest heavily in research and development, driving the steady expansion of its leading position in materials and process technologies and in product design and manufacturing. In particular, the Swatch Group engages in significant development activities in microelectronics and micromechanics. The Group is also active in the field of telecommunications and in the automobile and service sectors. Sports timing and measurement technologies, although not a core business, play a key role in terms of brand and Group visibility. A strong number of Swatch Group companies serve as official timekeepers at a variety of international sports events, including the Olympic Games.

"


http://www.swatchgroup.com/en/group_profile/history/today

 

[diagem]

Date: 5/1/2010 2:45:49 AM
Author: Serg

Date: 4/30/2010 4:33:40 PM
Author:oldminer
I would say the answer is ''No''. When a viewer looks at a diamond, they want to see lots of sparkle, pattern and plenty of bright light coming back to their eye, but mixed with brightness are some areas of relative darkness which show the pattern and allow concentrations of light to be seen as scintillation. If you think about getting the maximum light back, you''d construct a plain mirror which would send nearly all the light back to your eye without the benefit of the desired pattern , sparkle and contrast elements. It would fail to be as beautiful or desirable. Very few people would seek such a bright, yet uninteresting looking diamond.


Are there experts or consumers who would want to maximize light return beyond today''s Ideal Cut ranges if the trade off resulted in the direction of more light return yet less of the other important elements?


Do you think moderation near the top of light return, which is the way it is now, is the right way to describe what the best light performance range is? Or, are we incorrect? Should we seek bright light return faceting designs which give even greater amounts of light back knowing other elements must taper downwards to accomplish this?


What do you think? Do you disagree?

Dave,
there are several definitions for Light Return . It is depends to What zone of space you want return light and from what zone of space you can collect light
GIA return light to upper hemisphere(WLR) , others return light to one ''point zone'' for fixed or for several tilted diamond positions.
key point here is zone of space from which diamond could collect light when you calculate Light return. If diamond collects light from whole upper hemisphere ( even except head(ASET/IS) and may be body) then task to maximize Light return has not any sense. ( answer is any diamond with zero leakage . we know beautiful and ugly diamonds with low leakage, so maximization light return from whole hemisphere can not separate ugly diamonds from beautiful diamonds)

more correct task for Light return maximization when diamond collects light from small zones with random distribution .
''in other words we need maximize cut ability redirect light from single small light source with random position to consumer eyes '' such Light return maximization is very important and helpful

I agree Serg..., but logic (to me) says the more limited range of proportions/angles allowed (eg super precise cuts), the more limited redirection of light from various sources.
I am happy this thread came out as readers should understand "Maximum Light Return" does NOT mean more beautiful or Vice-Versa! (Thanks Dave).

Also I would like to point out to another miss-interpretation that I have been reading quite a often here on PS which CCL used above:

"....there are always going to be virtual facets that are out of phase with each other and tweaking this will result in a more beautiful diamond."

Maybe the word beautiful should be replaced with the word "uniform"?

CCL..., I admire the knowledge you have absorbed in a relative short time but do feel the urge to remind you that beauty is separate from science.
I am one who believes out-of-phase VF''s are beautiful as well.

 

[Serg]

Date: 5/3/2010 5:57:50 AM
Author: DiaGem

Date: 5/1/2010 2:45:49 AM

Author: Serg

Date: 4/30/2010 4:33:40 PM

Author:oldminer

I would say the answer is ''No''. When a viewer looks at a diamond, they want to see lots of sparkle, pattern and plenty of bright light coming back to their eye, but mixed with brightness are some areas of relative darkness which show the pattern and allow concentrations of light to be seen as scintillation. If you think about getting the maximum light back, you''d construct a plain mirror which would send nearly all the light back to your eye without the benefit of the desired pattern , sparkle and contrast elements. It would fail to be as beautiful or desirable. Very few people would seek such a bright, yet uninteresting looking diamond.



Are there experts or consumers who would want to maximize light return beyond today''s Ideal Cut ranges if the trade off resulted in the direction of more light return yet less of the other important elements?



Do you think moderation near the top of light return, which is the way it is now, is the right way to describe what the best light performance range is? Or, are we incorrect? Should we seek bright light return faceting designs which give even greater amounts of light back knowing other elements must taper downwards to accomplish this?



What do you think? Do you disagree?

Dave,

there are several definitions for Light Return . It is depends to What zone of space you want return light and from what zone of space you can collect light

GIA return light to upper hemisphere(WLR) , others return light to one ''point zone'' for fixed or for several tilted diamond positions.

key point here is zone of space from which diamond could collect light when you calculate Light return. If diamond collects light from whole upper hemisphere ( even except head(ASET/IS) and may be body) then task to maximize Light return has not any sense. ( answer is any diamond with zero leakage . we know beautiful and ugly diamonds with low leakage, so maximization light return from whole hemisphere can not separate ugly diamonds from beautiful diamonds)


more correct task for Light return maximization when diamond collects light from small zones with random distribution .

''in other words we need maximize cut ability redirect light from single small light source with random position to consumer eyes '' such Light return maximization is very important and helpful

I agree Serg..., but logic (to me) says the more limited range of proportions/angles allowed (eg super precise cuts), the more limited redirection of light from various sources.

I am happy this thread came out as readers should understand ''Maximum Light Return'' does NOT mean more beautiful or Vice-Versa! (Thanks Dave).


Also I would like to point out to another miss-interpretation that I have been reading quite a often here on PS which CCL used above:


''....there are always going to be virtual facets that are out of phase with each other and tweaking this will result in a more beautiful diamond.''


Maybe the word beautiful should be replaced with the word ''uniform''?


CCL..., I admire the knowledge you have absorbed in a relative short time but do feel the urge to remind you that beauty is separate from science.

I am one who believes out-of-phase VF''s are beautiful as well.

Yoram,

re:but logic (to me) says the more limited range of proportions/angles allowed (eg super precise cuts), the more limited redirection of light from various sources.

Please clarify your statement about limited range of proportions in detail . Could you please do it without connection to symmetry ?

 

[Paul-Antwerp]

Date: 5/2/2010 1:40:42 AM
Author: Karl_K
Dave,

No cut grading system takes every aspect of diamond performance into consideration.
This is something that Paul has been talking about lately.
Now he feels his particular visual balance is the best.
Brian feels his idea of visual balance is the best but it is different than Paul''s.
My favorites are different from both of them.

Karl,

I really need to distance myself from your words here. ''Visual balance'' is not a term that I believe in, as I feel that it implies that the improvement of one positive will be outweighed by a negative, and that is in my experience incorrect.

Take for instance the start of this thread, where maximization of light return is said to be achieved by a plain mirror. This is the approach of a fixed light-environment, combined with static analysis. In reality, that is not how diamonds are observed in real life.

Take that same mirror, so-called maximizing light return, and tilt it slightly, so that the light is not directed towards the observer anymore. Maximum suddenly became zero.

In that way, I fully agree with Sergey''s words earlier, that maximization is important and possible, in the sense of maximizing in an infinite possibility of light-environments. That clearly means that I am a true believer of ''maximization'' and not of ''visual balance''.

Live long,

 

[diagem]

Date: 5/3/2010 6:14:37 AM
Author: Serg


Yoram,

re:but logic (to me) says the more limited range of proportions/angles allowed (eg super precise cuts), the more limited redirection of light from various sources.

Please clarify your statement about limited range of proportions in detail . Could you please do it without connection to symmetry ?

Sergey..., when you have limited allowance in proportions/angles, chances are you will have great results in limited lighting environments...
When you have a wider scope of limitations it can achieve ''good'' results in plural light environments (eg we notice how some old-cuts perform better in a wider range of light environments).

 

[Serg]

Date: 5/3/2010 7:16:51 AM
Author: DiaGem

Date: 5/3/2010 6:14:37 AM

Author: Serg



Yoram,


re:but logic (to me) says the more limited range of proportions/angles allowed (eg super precise cuts), the more limited redirection of light from various sources.


Please clarify your statement about limited range of proportions in detail . Could you please do it without connection to symmetry ?

Sergey..., when you have limited allowance in proportions/angles, chances are you will have great results in limited lighting environments...

When you have a wider scope of limitations it can achieve ''good'' results in plural light environments (eg we notice how some old-cuts perform better in a wider range of light environments).

Yoram,

Are you speaking about round Cut and Labs cut grading for round cut?
Most Fancy cuts have not any limitation in proportion range yet. I am speaking about Fancy cuts, about new Fancy cuts.
I do not see any economical reasons to discuss about round cut more.
but for any cuts SET( not range) of good proportion( good for best redirect light to eyes) is very rare( limited)
if you want something best , it needs limited allowance.

Limitation is not evil, Wrong criteria for such limitation as a result of lack knowledge is real evil.

 

[Garry H (Cut Nut)]

Please see the example here using split mirrors. It is relevant to the discussion
http://www.gemology.ru/cut/english/grading1/4.htm