Light Return. Is maximization really the answer?

[Serg]

Date: 5/3/2010 7:47:02 AM
Author: 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

Garry, I think you gave wrong link
Do you mean

4 mirror examples on below pages:


http://www.gemology.ru/cut/english/grading1/8.htm

and
http://www.gemology.ru/cut/english/grading1/9.htm

?

 

[Garry H (Cut Nut)]

Yes, start here http://www.gemology.ru/cut/english/grading1/8.htm
(I copied the wrong page)

 

[diagem]

Date: 5/3/2010 7:32:06 AM
Author: 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.

No..., I am talking about Fancy Cuts... (always do/did

)
You say "most Fancy Cuts dont have limitations in proportion range yet"?
True..., most dont yet but IYO those who have, do they have great results in a wide variety of lighting environments?

 

[Serg]

Date: 5/3/2010 8:39:20 AM
Author: DiaGem

Date: 5/3/2010 7:32:06 AM

Author: 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.

No..., I am talking about Fancy Cuts... (always do/did

)

You say 'most Fancy Cuts dont have limitations in proportion range yet'?

True..., most dont yet but IYO those who have, do they have great results in a wide variety of lighting environments?

re: but IYO those who have, do they have great results in a wide variety of lighting environments?
usually NO, but It does not matter because
1) you can consider cuts with parameters outside LABs ranges as new Cuts( or you can add some facets and create modified Oval)
2) if Diamond industry will create 5-10 cuts better than RBC each year, LABS have not chance to create such limitations for these cuts . They are to slow for such race

 

[diagem]

Date: 5/3/2010 8:48:18 AM
Author: Serg

Date: 5/3/2010 8:39:20 AM
Author: DiaGem

Date: 5/3/2010 7:32:06 AM

Author: 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.

No..., I am talking about Fancy Cuts... (always do/did

)

You say ''most Fancy Cuts dont have limitations in proportion range yet''?

True..., most dont yet but IYO those who have, do they have great results in a wide variety of lighting environments?

re: but IYO those who have, do they have great results in a wide variety of lighting environments?
usually NO, but It does not matter because
1) you can consider cuts with parameters outside LABs ranges as new Cuts( or you can add some facets and create modified Oval)
2) if Diamond industry will create 5-10 cuts better than RBC each year, LABS have not chance to create such limitations for these cuts . They are to slow for such race

Sergey, I dont care for Lab results..., I care for real life results!
IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.

 

[Serg]

Yoram,

re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.

I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )
Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.

if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)
but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

 

[diagem]

Date: 5/3/2010 9:14:38 AM
Author: Serg
Yoram,

re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.

I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )
Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.

if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)
but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

Sergey..., I started this conversation because you wrote:

"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 "

Do you need wide or narrrow limitations to achieve that?

 

[ChunkyCushionLover]

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.

My point wasn't about whether in phase or out of phase VFs were beautiful or not beautiful that is something so subjective it will only distract from the purpose of this thread. My point was given the current diamond fancy designs they all necessarily have out of phase VFs but a static image(like an ASET) cannot accurately illustrate this. One can design(and some have designed) a brilliant cut diamond in almost any outline shape which gathers light almost exclusively from the overhead position (almost all ASET red in faceup static position) and I am loath to think that some would try to argue by definition this optimization removed contast or the other important properties like scintillation and fire. By definition tweaking with current facet designs doesn't involve removing all out of phase VFs and maximizing the static faceup view like a headlight, that is not the kind of modern maximization I see being studied nor being applied to new diamond cuts.

 

[Karl_K]

Date: 5/3/2010 6:35:22 AM
Author: 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.

Hi Paul,
I think you are missing part of the meaning of visual balance.
Discuss it with sir John.
At heart visual balance is separating the play of light from the physical diamond while using the physical diamond to controll the play of light.
Where each of us would set the balance of attributes is different and would be different for different cuts.
What is the difference from an OEC to an RB? A different visual balance.
A diamond without balance is a mirror or a lump of coal.

 

[Karl_K]

Date: 5/3/2010 12:09:08 PM
Author: ChunkyCushionLover
My point wasn't about whether in phase or out of phase VFs were beautiful or not beautiful that is something so subjective it will only distract from the purpose of this thread. My point was given the current diamond fancy designs they all necessarily have out of phase VFs but a static image(like an ASET) cannot accurately illustrate this. One can design(and some have designed) a brilliant cut diamond in almost any outline shape which gathers light almost exclusively from the overhead position (almost all ASET red in faceup static position) and I am loath to think that some would try argue by definition this optimization removed contast or the other important properties like scintillation and fire. By definition tweaking with current facet designs doesn't involve removing all out of phase VFs and maximizing the static faceup view like a headlight, that is not the kind of modern maximization I see being studied nor being applied to new diamond cuts.

bravo, someone has been paying attention

You are right playing with phase based contrast is where the innovations in diamond design are going to come from.
It is the missing link tying diamond performance to virtual facets.
The big question is if cutters are going to be able to cut the diamonds tight enough to the spec to make it work on a large scale.
On a small scale cutters like DiaGem and Paul and their shops can make it work but can it scale to 10000 diamonds a year?
Right now I don't think so but Serg is working on it.

 

[Karl_K]

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

That is up to the diamond designer, the tighter it can be cut the more complex I can make my optimizations and it makes possible designs and performance and looks not possible with wide ranging angles.
I can design in a wide range of redirection.

 

[Paul-Antwerp]

Date: 5/3/2010 12:14:12 PM
Author: Karl_K

Date: 5/3/2010 6:35:22 AM
Author: 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.

Hi Paul,
I think you are missing part of the meaning of visual balance.
Discuss it with sir John.
At heart visual balance is separating the play of light from the physical diamond while using the physical diamond to controll the play of light.
Where each of us would set the balance of attributes is different and would be different for different cuts.
What is the difference from an OEC to an RB? A different visual balance.
A diamond without balance is a mirror or a lump of coal.

Karl,

I am sorry, but I have to be extremely clear and dry here.

The reason why I am distancing myself from your words is because you are taking the tagline of one vendor, then use your and my name in connection with that concept, as if I agree with the concept, and only offer a slightly different taste of the same as he and you.

I am sorry, my friend, but you crossed a line that I cannot accept being crossed.

In this world of shameless copying of taglines, often nonsensical ones like ''cutting at 100x magnification'', I clearly want to distance myself from the tagline ''visual balance'', especially in the context of non-maximisation of cutting.

Live long,

 

[Rockdiamond]

I really love this thread.

An analogy: Ford decides to classify their cars based on how much "oomph" they have.
GM, of course lacks ooomph- they can brag about the "zing" their models have.

We're rearranging angels on the head of a pin trying to define, and quantify some of these aspects.
This is way different from discussing specific facet designs, or cutting techniques which are "fixed" or hard assets. How one perceives the way the light reacts to these things is personal, and really can't be quantified - for many reasons. Not the least of which is agreeing on a consistent light source, or manner of viewing.

It's been brought up that sellers may use these names, and resultant measurements to charge more for stones that are claimed to be better due to increased light return- or other "performance attributes"
I honestly believe ( and have hard experience) that some stones are worth more, based on the precision of cutting. Where I see the problem is when that aspect gets trans-mutated into a direct relationship with beauty.

Personally I have found a combination of photos, and video can convey a lot more of the diamond's personality than terms such as "light return" attempt to do.

 

[Karl_K]

Date: 5/3/2010 3:02:13 PM
Author: Paul-Antwerp

Karl,


I am sorry, but I have to be extremely clear and dry here.


The reason why I am distancing myself from your words is because you are taking the tagline of one vendor, then use your and my name in connection with that concept, as if I agree with the concept, and only offer a slightly different taste of the same as he and you.


I am sorry, my friend, but you crossed a line that I cannot accept being crossed.


In this world of shameless copying of taglines, often nonsensical ones like ''cutting at 100x magnification'', I clearly want to distance myself from the tagline ''visual balance'', especially in the context of non-maximisation of cutting.


Live long,

ok fair enough Paul.
I can see your point.
I could care less about the tagline, I like the concept.

 

[diagem]

Date: 5/3/2010 12:37:45 PM
Author: Karl_K

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

That is up to the diamond designer, the tighter it can be cut the more complex I can make my optimizations and it makes possible designs and performance and looks not possible with wide ranging angles.
I can design in a wide range of redirection.

Well..., you already witnessed real cut limitations due to scan/tool error.
What is possible virtualy is not always possible practically

.

I guess thats why wide range makes more sense (in many factors.)

 

[diagem]

Date: 5/3/2010 12:09:08 PM
Author: ChunkyCushionLover

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.

My point wasn''t about whether in phase or out of phase VFs were beautiful or not beautiful that is something so subjective it will only distract from the purpose of this thread. My point was given the current diamond fancy designs they all necessarily have out of phase VFs but a static image(like an ASET) cannot accurately illustrate this. One can design(and some have designed) a brilliant cut diamond in almost any outline shape which gathers light almost exclusively from the overhead position (almost all ASET red in faceup static position) and I am loath to think that some would try to argue by definition this optimization removed contast or the other important properties like scintillation and fire. By definition tweaking with current facet designs doesn''t involve removing all out of phase VFs and maximizing the static faceup view like a headlight, that is not the kind of modern maximization I see being studied nor being applied to new diamond cuts.

OK..., it makes more sense now, I just wish you would use the correct terminology which isnt beauty.
BTW..., contrast/scintillation & fire are also subjective & dependant on more factors that just tweaking current facet designs.

 

[Karl_K]

Date: 5/3/2010 5:55:45 PM
Author: DiaGem

Date: 5/3/2010 12:37:45 PM

Author: Karl_K

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

Author: DiaGem

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.

That is up to the diamond designer, the tighter it can be cut the more complex I can make my optimizations and it makes possible designs and performance and looks not possible with wide ranging angles.

I can design in a wide range of redirection.

Well..., you already witnessed real cut limitations due to scan/tool error.

What is possible virtualy is not always possible practically

.


I guess thats why wide range makes more sense (in many factors.)

Today a lot of it is not possible, but someday it will be then I can take it to the next level.

 

[diagem]

Date: 5/3/2010 12:20:59 PM
Author: Karl_K

Date: 5/3/2010 12:09:08 PM
Author: ChunkyCushionLover
My point wasn''t about whether in phase or out of phase VFs were beautiful or not beautiful that is something so subjective it will only distract from the purpose of this thread. My point was given the current diamond fancy designs they all necessarily have out of phase VFs but a static image(like an ASET) cannot accurately illustrate this. One can design(and some have designed) a brilliant cut diamond in almost any outline shape which gathers light almost exclusively from the overhead position (almost all ASET red in faceup static position) and I am loath to think that some would try argue by definition this optimization removed contast or the other important properties like scintillation and fire. By definition tweaking with current facet designs doesn''t involve removing all out of phase VFs and maximizing the static faceup view like a headlight, that is not the kind of modern maximization I see being studied nor being applied to new diamond cuts.

bravo, someone has been paying attention

You are right playing with phase based contrast is where the innovations in diamond design are going to come from.
It is the missing link tying diamond performance to virtual facets.
The big question is if cutters are going to be able to cut the diamonds tight enough to the spec to make it work on a large scale.
On a small scale cutters like DiaGem and Paul and their shops can make it work but can it scale to 10000 diamonds a year?
Right now I don''t think so but Serg is working on it.

I agree about innovations in the light performance arena..., but I believe innovations will also exist in the sculpturing of the Diamond material.
Some with more light behaviour importance & some with less.

Only the future will tell.

 

[diagem]

Date: 5/3/2010 6:30:58 PM
Author: Karl_K

Date: 5/3/2010 5:55:45 PM
Author: DiaGem

Date: 5/3/2010 12:37:45 PM

Author: Karl_K

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

Author: DiaGem

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.

That is up to the diamond designer, the tighter it can be cut the more complex I can make my optimizations and it makes possible designs and performance and looks not possible with wide ranging angles.

I can design in a wide range of redirection.

Well..., you already witnessed real cut limitations due to scan/tool error.

What is possible virtualy is not always possible practically

.


I guess thats why wide range makes more sense (in many factors.)

Today a lot of it is not possible, but someday it will be then I can take it to the next level.

RE> "Today a lot of it is not possible, but someday it will hopefully be then I can take it to the next level."

Unfortunately I dont see it in the near future as to many factors have limitations..., but who knows.

 

[Karl_K]

Date: 5/3/2010 6:33:30 PM
Author: DiaGem
I agree about innovations in the light performance arena..., but I believe innovations will also exist in the sculpturing of the Diamond material.

Some with more light behaviour importance & some with less.


Only the future will tell.

yep, the innovations depend on each other.
Better more efficient and more accurate cutting makes for more advanced designs and more advanced designs once they take off make it worth while to make the investment.
If the tools and designs can increase yield and or sell at a higher price they will take off much faster.

 

[Serg]

Date: 5/3/2010 11:35:50 AM
Author: DiaGem

Date: 5/3/2010 9:14:38 AM

Author: Serg

Yoram,


re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.


I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )

Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.


if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)

but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

Sergey..., I started this conversation because you wrote:


''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 ''


Do you need wide or narrrow limitations to achieve that?

Yoram,

I do not need any limitation to achieve this goal, but result will have very narrow range of proportions.

 

[partgypsy]

I''m not going to even look at the technical responses but my response would be yes I think emphasizing light return only can go too far. Just like too many facets on a smaller stone.
I am especially thinking of cutting in gemstones where sometimes the more technical cuts (even concave cutting) can look flat and "dry" to me, while other cuts that perhaps don''t have as much total return light-wise look lively and "juicy" to me. Maybe that''s partly due to contrast, I don''t know.

 

[diagem]

Date: 5/4/2010 7:23:25 AM
Author: Serg

Date: 5/3/2010 11:35:50 AM
Author: DiaGem

Date: 5/3/2010 9:14:38 AM

Author: Serg

Yoram,


re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.


I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )

Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.


if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)

but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

Sergey..., I started this conversation because you wrote:


''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 ''


Do you need wide or narrrow limitations to achieve that?

Yoram,

I do not need any limitation to achieve this goal, but result will have very narrow range of proportions.

Kinda makes sense..., but IMO, the average finer cuts should act nicely as well as they are not tuned to specific lighting scenarios.
For example..., take an Ex cut RB, some lighting dont compliment them (direct sun as an example).

On the other hand..., precision step cuts surprise me positively in most lighting environments including direct sunlight.

 

[Serg]

Date: 5/4/2010 3:55:38 PM
Author: DiaGem

Date: 5/4/2010 7:23:25 AM

Author: Serg

Date: 5/3/2010 11:35:50 AM

Author: DiaGem

Date: 5/3/2010 9:14:38 AM


Author: Serg


Yoram,



re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.



I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )


Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.



if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)


but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

Sergey..., I started this conversation because you wrote:



''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 ''



Do you need wide or narrrow limitations to achieve that?

Yoram,


I do not need any limitation to achieve this goal, but result will have very narrow range of proportions.

Kinda makes sense..., but IMO, the average finer cuts should act nicely as well as they are not tuned to specific lighting scenarios.

For example..., take an Ex cut RB, some lighting dont compliment them (direct sun as an example).


On the other hand..., precision step cuts surprise me positively in most lighting environments including direct sunlight.

re:the average finer cuts should act nicely as well as they are not tuned to specific lighting scenarios.
of course. It is reason why I prefer goal "maximize cut ability redirect light from single small light source with random position to consumer eyes "


re:take an Ex cut RB, some lighting dont compliment them (direct sun as an example)

"Direct sun". What is exactly "Direct sun" light ? where were Sun, You, Diamond during your tests? Was sun on front you?( from girdle side)?
or was sun behind you? EX RBC mainly collects light around your head

 

[diagem]

Date: 5/4/2010 4:15:09 PM
Author: Serg

Date: 5/4/2010 3:55:38 PM
Author: DiaGem

Date: 5/4/2010 7:23:25 AM

Author: Serg

Date: 5/3/2010 11:35:50 AM

Author: DiaGem

Date: 5/3/2010 9:14:38 AM


Author: Serg


Yoram,



re:IMO the more limitations in the proportions the more limitation in the lighting options!That is my opinion.



I do not believe what you can find many consumer who are interesting to buy diamond for very limited range of light options.( I know only one such example from Garry-NightClub )


Most consumer prefer diamonds with great light performance for big range light environment what could be achieved only in narrow parameter range.



if you your task to create different diamonds for different light environments you need use big range of proportions( but for each solution you will again use very limited range)


but if you task to create well balanced diamond for many light environments you will use very narrow range for cut proportions

Sergey..., I started this conversation because you wrote:



'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 '



Do you need wide or narrrow limitations to achieve that?

Yoram,


I do not need any limitation to achieve this goal, but result will have very narrow range of proportions.

Kinda makes sense..., but IMO, the average finer cuts should act nicely as well as they are not tuned to specific lighting scenarios.

For example..., take an Ex cut RB, some lighting dont compliment them (direct sun as an example).


On the other hand..., precision step cuts surprise me positively in most lighting environments including direct sunlight.

re:the average finer cuts should act nicely as well as they are not tuned to specific lighting scenarios.
of course. It is reason why I prefer goal 'maximize cut ability redirect light from single small light source with random position to consumer eyes '


re:take an Ex cut RB, some lighting dont compliment them (direct sun as an example)

'Direct sun'. What is exactly 'Direct sun' light ? where were Sun, You, Diamond during your tests? Was sun on front you?( from girdle side)?
or was sun behind you? EX RBC mainly collects light around your head

Was just an example (I know its not a single small light source)..., but I mean direct (from above), no obstruction.
Ex RB's look constantly grayish in overall appearance..., some average fine RB's handle direct sunlight better, they can look better as the contrast is not uniformed as in the Ex RB's.

 

[Rhino]

Great discussion. When I saw the title of this thread I thought has Dave gone nuts? Who doesn''t want max bling in their diamond? After reading your thoughts I couldn''t agree more Dave.

In my personal study and observance of top performing diamonds over the years I''ve come to think of this ultimately as the correct positioning of windows & mirrors to achieve maximum beauty within the cutting style of the particular diamond/shape. The windows being the facets on the crown. The mirrors being those facets on the pavilion. The best chemistry is achieved when the windows are effectively grabbing light from the most efficient (or brightest) resources in the environment while the mirrors are effectively kicking those reflections grabbed by the windows back to the eyes of the observer in a manner that is pleasing to their eye.

With the perfect geometry achieved (in symmetry and proportions) the nature of those reflections will be determined by the facet structure/design and of course virtual facets.

The antithesis of light return when it comes to diamond is the visual results of leakage and/or head/body obstruction which is necessary for providing this contrast between bright reflections. Too much of it will result in either a glassy/watery appearance (which most consumers do not find pleasing to the eye) as well as too much head/body obstruction (resulting in too much darkness reflected back to the eye.

What is great about diamond is those mirrors can be made larger or smaller resulting in either an emphasis on broad flash, pin flash or a combo of the 2. There are extremes in differing cuts which ultimately the end consumer must decide is either more or less appealing to their own eyes and taste. Yes there is not one technology that can communicate this more effectively than human observation which is why I never place all my eggs in one technological basket.

 

[Serg]

Yoram,

re:Was just an example (I know its not a single small light source)..., but I mean direct (from above), no obstruction.
Ex RB's look constantly grayish in overall appearance..., some average fine RB's handle direct sunlight better, they can look better as the contrast is not uniformed as in the Ex RB's.


are speaking about "direct sun" or "direct sun sky " light conditions?

seems what you are speaking about "direct cloudless sky "
did all diamonds in your tests catch only Sky ?
if diamond redirect sun to your eye , diamond should become dark except 1-2very bright flashes

 

[diagem]

Date: 5/5/2010 5:41:21 AM
Author: Serg
Yoram,

re:Was just an example (I know its not a single small light source)..., but I mean direct (from above), no obstruction.
Ex RB''s look constantly grayish in overall appearance..., some average fine RB''s handle direct sunlight better, they can look better as the contrast is not uniformed as in the Ex RB''s.


are speaking about ''direct sun'' or ''direct sun sky '' light conditions?

seems what you are speaking about ''direct cloudless sky ''
did all diamonds in your tests catch only Sky ?
if diamond redirect sun to your eye , diamond should become dark except 1-2very bright flashes

Thats what I mean..., not all Diamonds become dark...
Repeatable uniform in contrast will produce grey (dark) appearance consistently.
a wider variety of contrast will produce different appearance & can appear lively vs becoming dark.

 

[oldminer]

If one is going to "measure" light return and light performance, one must uise a tool which is sensitive over the entire potential range of light return, from total dark to maximum concentrated light. In order to do this, one must use only enough light that no matter how much is refracted and concentrated back to the measuring sensor, that the sensor will not become overexposed and beyond its capacity to measure the amount of returning light. This means then that the lighting used to measure the effectiveness of cut cannot be super strong as the maximum returned must not exceed the ability fo the measuring sensor to differentiate that maximum from amounts below the maximum amount. Too much light used will make less than a maximum return potentially measure the identically as a greater amount returned to the sensor. Overwhelming the measuring sensor leads to improper assessment of the effectiveness of the cut and the light return.

Selecting a proper standardized lighting environment is critical to making such assessments in a repeatable and meaningful way. Using strong lighting which blows out the ability of the sensor to discriminate at the top end will create errors in which diamond cut has the greatest light return capability. The greatest light return capability does not automatically equate to the best cut or the best diamond. But, it is a solid, objective measure, which can be counted on when a grading scale is created based on human preferences.

 

[diagem]

Date: 5/8/2010 10:18:33 AM
Author: oldminer
If one is going to ''measure'' light return and light performance, one must uise a tool which is sensitive over the entire potential range of light return, from total dark to maximum concentrated light. In order to do this, one must use only enough light that no matter how much is refracted and concentrated back to the measuring sensor, that the sensor will not become overexposed and beyond its capacity to measure the amount of returning light. This means then that the lighting used to measure the effectiveness of cut cannot be super strong as the maximum returned must not exceed the ability fo the measuring sensor to differentiate that maximum from amounts below the maximum amount. Too much light used will make less than a maximum return potentially measure the identically as a greater amount returned to the sensor. Overwhelming the measuring sensor leads to improper assessment of the effectiveness of the cut and the light return.

Selecting a proper standardized lighting environment is critical to making such assessments in a repeatable and meaningful way. Using strong lighting which blows out the ability of the sensor to discriminate at the top end will create errors in which diamond cut has the greatest light return capability. The greatest light return capability does not automatically equate to the best cut or the best diamond. But, it is a solid, objective measure, which can be counted on when a grading scale is created based on human preferences.

David, we cant control ''real life'' lighting..., so maybe measuring light return is not really an objective measure??