GIA Diamond Cut Grading: Problems with Diamond Dock

[pricescope]

This thread continues previous discussions:
GIA EX: Let the buyer beware...
GIA Ex: The Consumers Perspective and the Technologies

Serg gave me a brief lecture, which I'm trying to summarize here.

1. One have to understand why diamond looks bright

1. Floor is darker than ceilings. If you look at the ceilings directly, ceilings don't look bright. However, take a small mirror, point to the ceiling – you’ll see bright ceilings in the mirror on the floor background. Ceilings reflected in the mirror on dark background (floor) appear bright.
2. To see bright flashes from a diamond background should be much darker than secondary or primary light sources. In consumers light condition most light sources are much more bright than background (floor).
3. In real life background is much darker than other light sources and light coming from light sources of different brightness and from different angles. Such bright light sources cover big (or biggest) part of upper hemisphere.

2. Why viewing diamonds in GIA's DD is incorrect for diamond cut grading.

1. In DiamondDock white walls are very close to the bright light source therefore the background is some orders of magnitude brighter than in reality. This causes the main difference between real life environment. Balance between background brightness and more bright light sources in Diamond Dock is incorrect. A few light sources has brightness stronger than background, such light sources cover small part of the upper hemisphere.
2. In this environment, human eyes adjust to the bright background and the only flashes/reflections that will be visible in diamonds come directly from the light source. All other reflections will be much darker than the background and therefore invisible to the human eye.
3. Angular size of the light source is relatively small (few degrees). Therefore, only selected group of cuts will benefit from this particular lightning setting. (Even Brilliant Scope has 5 light source positions.) This skews the results toward certain group of diamonds that look good in this particular environment without guarantee that these diamonds will look good in real live and vice versa.

3. Diamond Dock pros and cons

• Pros: standardized environment - all other light sources won’t affect the results.
• Cons: diamonds only take light from narrow light angle. Prefers certain group of diamonds that selectively reflect light from the light source in that specific angular schema.

4. Demonstration:

Small change in pavilion angle 0.8° significantly rotates out-coming rays (see picture below). As a result, diamonds of certain proportions won’t reflect light from the source into observer eyes in this particular setting while still reflecting light from the sources under different angles.

It was illustrated earlier here: https://www.pricescope.com/community/threads/how-lighting-can-influence-on-grade-appearance.38583/page-2

5. Conclusion:

• Selecting correct (close to real live) lightning environment is crucial for adequate diamond cut grading. This includes brightness and angular positions of the light sources as well as brightness of the background. There are several real live lightning environments and different diamonds can look better in some of them and vice versa.
• Any method of light performance evaluation with fixed angular position(s) of the diamond and light source(s) (including GIA DD, Brilliancescope, Imagem, etc) should suffer from this problem by favoring diamonds of certain proportions.
• In theory it is possible to design evaluation devices to favor any set of specific proportions.

 

[pricescope]

This picture illustrates reverse rays: you can see reflection of the light source only for diamonds of certain proportions.

 

[Stephan]

Thank you so much for this information!

 

[strmrdr]

couple questions:
1> diamonds are often viewed at angles like that on the hand. How is that different?

2> the human head is always moving so wouldnt they pick up the other beams graphed there?

unsupported humans just dont keep their head in one position.
Also odds are that they would move for max brightness when looking at it.
From my recall of observing people looking at diamonds most would move to find the brightest look.

From a fixed camera position it would be a much bigger issue.

 

[JohnQuixote]

Date: 3/15/2006 1:10:57 PM
Author:Pricescope

5. Conclusion:

• Selecting correct (close to real live) lightning environment is crucial for adequate diamond cut grading. This includes brightness and angular positions of the light sources as well as brightness of the background. There are several real live lightning environments and different diamonds can look better in some of them and vice versa.

This has puzzled me since entering the trade: Trade assessment and sales environments have little correlation to actual environments in which pedestrians view diamonds. Lab evaluations involve fluorescent desk lamps. Common sales situations involve overhead spotlighting. Now those are the environments DD quasi-replicates to assess cut, but they are not typical human illumination scenarios.

Our typical illumination scenarios see lighting sources farther away - daylight (filtered daylight), ceiling lighting, etc. And, as long as it's being discussed, who else recognizes that many many social situations occur at night with low light conditions present - restaurants, lounges, casual parties, outdoor patios, typical living rooms, etc? This deserves consideration.

• Any method of light performance evaluation with fixed angular position(s) of the diamond and light source(s) (including GIA DD, Brilliancescope, Imagem, etc) should suffer from this problem and favoring diamonds of certain proportions. In theory it is possible to design evaluation device to favor any set of specific proportions.

And - conversely - it is possible to design a diamond that will max out the metric of any such evaluative environment.

 

[pricescope]

Picture of GIA Diamond Dock. Details can be found here: http://www.gia.edu/geminstrument/myProducts.cfm?CategoryID=3

 

[jasontb]

If the DD is as worthless as the OP and Serg seem to be saying, what does that say about the GIA? Is this just a cash-cow for them? Did they perform research on lighting conditions to come up with this design? And if so, are we saying that they are so dumb that their years of scientific research can be negated with a few qualitative statements?

That thing is too expensive. $1400

$30 worth of bent up sheet metal. $2 worth of paint. And appearantly a $1000 light?

 

[JohnQuixote]

Date: 3/15/2006 2:33:32 PM
Author: jasontb
If the DD is as worthless as the OP and Serg seem to be saying, what does that say about the GIA? Is this just a cash-cow for them? Did they perform research on lighting conditions to come up with this design? And if so, are we saying that they are so dumb that their years of scientific research can be negated with a few qualitative statements?

That thing is too expensive. $1400

$30 worth of bent up sheet metal. $2 worth of paint. And appearantly a $1000 light?

Jason, read the first post, here.

 

[Rhino]

I appreciate a healthy dose of skepticism and I am a firm believer in putting any technology through rigorous testing, primarily how it corellates to human observation. I am all for that.

My question is simple.

What if you take a pair of comparison stones and observe them for brightness in

a. Standard daylight environments such as outside on a cloudy day.
b. Outside in sunlight but in the shade.
c. Standard overhead office lighting (overhead fluorescents)
d. Diffuse LED''s (as opposed to direct)
e. Then lastly the GIA DiamondDock

and you see the same exact optical phenomena in each and every instance?

 

[dhog]

Date: 3/15/2006 4:41:57 PM
Author: Rhino
I appreciate a healthy dose of skepticism and I am a firm believer in putting any technology through rigorous testing, primarily how it corellates to human observation. I am all for that.


My question is simple.


What if you take a pair of comparison stones and observe them for brightness in


a. Standard daylight environments such as outside on a cloudy day.

b. Outside in sunlight but in the shade.

c. Standard overhead office lighting (overhead fluorescents)

d. Diffuse LED's (as opposed to direct)

e. Then lastly the GIA DiamondDock


and you see the same exact optical phenomena in each and every instance?

I for one would question your results that are in direct
conflict with all other test eq. that you use.

How can you justify your use of this equipment
after you just claimed its results are invalid.

I know nothing about diamonds but I do know that if
5 or 6 pieces of equipment told me the same thing
I WOULD BELIEVE THEM AND QUESTION THE ONE PIECE
THAT WAS DIFFERENT unless their is other reasons.

 

[strmrdr]

Date: 3/15/2006 5:02:16 PM
Author: dhog

Date: 3/15/2006 4:41:57 PM

Author: Rhino

I appreciate a healthy dose of skepticism and I am a firm believer in putting any technology through rigorous testing, primarily how it corellates to human observation. I am all for that.



My question is simple.



What if you take a pair of comparison stones and observe them for brightness in



a. Standard daylight environments such as outside on a cloudy day.


b. Outside in sunlight but in the shade.


c. Standard overhead office lighting (overhead fluorescents)


d. Diffuse LED''s (as opposed to direct)


e. Then lastly the GIA DiamondDock



and you see the same exact optical phenomena in each and every instance?

I for one would question your results that are in direct

conflict with all other test eq. that you use.


How can you justify your use of this equipment

after you just claimed its results are invalid.


I know nothing about diamonds but I do know that if

5 or 6 pieces of equipment told me the same thing

I WOULD BELIEVE THEM AND QUESTION THE ONE PIECE

THAT WAS DIFFERENT unless their is other reasons.

What your missing is that all 6 could use different lighting and give different results.
The top 5 things affecting observed diamond performance are:
lighting
lighting
lighting
envirment
cut

No one cut is tops in all lighting conditions.
A diamond cut for that specific condition will look better while likely worse in another.
The real fight is over which light conditions are more important and which the cutters should be rewarded for cutting diamonds with more performance in.
That is what the fight is about with the painting.

Paint the girdles and lower the lgf% and you get better low light performance at the expence of other conditions.

steep/deeps are another rant :}

 

[Rhino]

Date: 3/15/2006 5:02:16 PM
Author: dhog

Date: 3/15/2006 4:41:57 PM
Author: Rhino
I appreciate a healthy dose of skepticism and I am a firm believer in putting any technology through rigorous testing, primarily how it corellates to human observation. I am all for that.


My question is simple.


What if you take a pair of comparison stones and observe them for brightness in


a. Standard daylight environments such as outside on a cloudy day.

b. Outside in sunlight but in the shade.

c. Standard overhead office lighting (overhead fluorescents)

d. Diffuse LED''s (as opposed to direct)

e. Then lastly the GIA DiamondDock


and you see the same exact optical phenomena in each and every instance?

I for one would question your results that are in direct
conflict with all other test eq. that you use.

How can you justify your use of this equipment
after you just claimed its results are invalid.

I know nothing about diamonds but I do know that if
5 or 6 pieces of equipment told me the same thing
I WOULD BELIEVE THEM AND QUESTION THE ONE PIECE
THAT WAS DIFFERENT unless their is other reasons.

Hi dhog,

Which results did I claim were invalid? I''m not talking about technologies, I''m talking about visual observation with the human eyes in each of these environments that depict various elemens of brightness. In the other thread I was pointing out that, for the first time, we had a diamond that visually appeared brighter than technologies were suggesting which is a rare occurence in our experience using them. The piece of equipment in question here is the newly released GIA DiamondDock. If visual observation in all those lighting environments agrees with the visual observation in the DiamondDock, what does common sense logic tell us about the DiamondDock?

 

[michaelgem]

Commonality between DiamondDock and typical illumination circumstances.

Addressing a rewording of Rhino''s question: What if you take a pair of comparison stones and judge them for brightness in many typical lighting and viewing circumstances and lastly in the GIA DiamondDock, and you observe that one of the pair is consistently brighter?

This is what he has found, which suggests to him that DiamondDock is a reasonable standardized illumination for predicting diamond brightness in typical lighting. (At least for the pairs he has tested.)

Let''s consider for a minute how this could be true. There would have to be salient properties of the lighting and viewing circumstances in common with DiamondDock causing similar optical responses in the diamonds.

One important commonality in typical lighting and in DiamondDock is the presence of the same head and torso obstruction when the diamonds are observed from similar angles and viewing distances.

A diamond like 41.2/35 may be consistently preferred over 40.75/34.5, because it better avoids reflecting from angles close to the line-of-sight between the viewer’s eye and the diamond, where there is a relative absence of light.

If you are using a desk lamp or DiamondDock for illumination, and you tilt the diamond toward your eyes, the main illumination will be absent from the vicinity of your line-of-sight just as it is when the absence is due to observer obstruction.

This favors the 41.2/35, which better avoids observer obstruction, and could explain why Jonathan and his customers consistently observed the same preference in every viewing circumstance including DiamondDock.

I''m just saying...........

Michael Cowing

www.acagemlab.com

 

[tarssarb]

Date: 3/15/2006 5:33:15 PM
Author: strmrdr




What your missing is that all 6 could use different lighting and give different results.
The top 5 things affecting observed diamond performance are:
lighting
lighting
lighting
envirment
cut

No one cut is tops in all lighting conditions.
A diamond cut for that specific condition will look better while likely worse in another.
The real fight is over which light conditions are more important and which the cutters should be rewarded for cutting diamonds with more performance in.
That is what the fight is about with the painting.

Paint the girdles and lower the lgf% and you get better low light performance at the expence of other conditions.

steep/deeps are another rant :}

This discussion suggest that the understanding of diamonds and lighting is better understood than it really is.
Prove me wrong.

I have a tight bezel with no light entering the pavillion.
I want it to look great in a cubicle at work: what are my specs I need
No I want it to look great in a restaurant: should I shorten the LGF? THat's it? Or what angle change do I need
Ok now, I bought a premium and I don't want it to look dark when my sweetie is walking around outside. What now?
Wait, fire is most important... and I have no light coming in the pavillion, is this even possible?

Frankly, if these were answerable, then the best cert would be simply a data file of geometry with numerous paid services to tell you the true benefits of the cut. That would replace aga, gia, egl, etc with sarin or helium or what not.

Back to topic, I think the current situation in 99% of jewelry stores is halogen spot lights. Oh, didn't they mention you can stand over there by the fluorescent lights? Oh yeah, just put it under the desk and watch is still shimmer. It sucks. You think everything looks good in dd, well put it under a spot light.

The diamond dock makes sense in concept even if the execution is flawed. But if the execution is so poor, then the relative answers to the above question would be easy.

Rhino, I feel sorry you were attack back in the other thread. I noticed the same thing you illuded to in the other thread regarding 8* in jewelry lighting. About your attacks, business is business and partnerships fail for numerous reasons, mostly personality based. It isn't any different from any other relationship. What a joke.

 

[Serg]

re:And - conversely - it is possible to design a diamond that will max out the metric of any such evaluative environment.

John,

Such statement is not obviously at least( Even could be wrong) . I do not know how it could be done. You can optimize limited number parameters of any cut for fixed ilumination. But How will you find BEST TYPE of CUT for this illumination? How do you know what is maximum?


re:In theory it is possible to design evaluation device to favor any set of specific proportions.

It is easy. Sometimes back task is much more easy than direct task.

 

[Garry H (Cut Nut)]

Date: 3/15/2006 1:10:57 PM
Author:Pricescope
This thread continues previous discussions:
GIA EX: Let the buyer beware...
GIA Ex: The Consumers Perspective and the Technologies

Serg gave me a brief lecture, which I''m trying to summarize here.

1. One have to understand why diamond looks bright

1. Floor is darker than ceilings. If you look at the ceilings directly, ceilings don''t look bright. However, take a small mirror, point to the ceiling – you’ll see bright ceilings in the mirror on the floor background. Ceilings reflected in the mirror on dark background (floor) appear bright.
   GH - I tried this and it is true most of the time - but not in a room with suspended lighting, and not in a room with big windows and no lights turned on.
   
2. To see bright flashes from a diamond the background should be much darker than secondary or primary light sources. In consumers light condition most light sources are much more bright than background (floor). so there fore the brighter diamond sparkels against the less bright background
   
3. In real life background is much darker than other light sources and light coming from light sources of different brightness and from different angles. Such bright light sources cover big (or biggest) part of upper hemisphere. the assumption is that our heads are above the diamonds, which is true most of the time - but occasionally you will see a woman wearing diamond earringsa or pendant standing with her back to a bright window say - and then the diamonds are impossible to see anyway.

2. Why viewing diamonds in GIA''s DD is incorrect for diamond cut grading.

1. In DiamondDock white walls are very close to the bright light source therefore the background is some orders of magnitude brighter than in reality. This causes the main difference between real life environment. Balance between background brightness and more bright light sources in Diamond Dock is incorrect. A few light sources has brightness stronger than background, such light sources cover small part of the upper hemisphere.
   DD and the trays have a very flat matt painted gray surface which is just a little bit darker gray than this gray screen shade on Pricescope. They have not made it too light and reflective.
2. In this environment, human eyes adjust to the bright background and the only flashes/reflections that will be visible in diamonds come directly from the light source. All other reflections will be much darker than the background and therefore invisible to the human eye.
   this is true - the lighting makes it easy to see brighter sparkles - but only those that come from a very narrow area where the lights are:
   
3. Angular size of the light source is relatively small (few degrees). Th lights are 33cm (13 inches) above the base or furthest away pooint inside DD - and the two tubes - covered by a diffuser - are about 8cm from one side to another side. I think this makes about 14 degrees of area that could produce a bright sparkle in one plane, and the tube length of about 42cm? at 33cm is about 80 degrees of illuminatyed area - the walls are not bright enough to create a sparkle, and unless there is another bright ceiling light just above the observers head - there is no way a diamond could get another source of sparkle light. I guess that means the potential light sources that can provide a sparkle are restricted to less than 1/10th the available hemishpere. Therefore, only selected group of cuts will benefit from this particular lightning setting. (Even Brilliant Scope has 5 light source positions.) This skews the results toward certain group of diamonds that look good in this particular environment without guarantee that these diamonds will look good in real live and vice versa.

3. Diamond Dock pros and cons

• Pros: standardized environment - all other light sources won’t affect the results.
  
• Cons: diamonds only take light from narrow light angle. Prefers certain group of diamonds that selectively reflect light from the light source in that specific angular schema. many fancy shaped stones would die - I should have checked for this - Rhino - what is your opinion with various other stones?

4. Demonstration:

Small change in pavilion angle 0.8° significantly rotates out-coming rays (see picture below). As a result, diamonds of certain proportions won’t reflect light from the source into observer eyes in this particular setting while still reflecting light from the sources under different angles.

It was illustrated earlier here: https://www.pricescope.com/community/threads/how-lighting-can-influence-on-grade-appearance.38583/page-2

5. Conclusion:

• Selecting correct (close to real live) lightning environment is crucial for adequate diamond cut grading. This includes brightness and angular positions of the light sources as well as brightness of the background. There are several real live lightning environments and different diamonds can look better in some of them and vice versa.
  
• Any method of light performance evaluation with fixed angular position(s) of the diamond and light source(s) (including GIA DD, Brilliancescope, Imagem, etc) should suffer from this problem by favoring diamonds of certain proportions.
  
• In theory it is possible to design evaluation devices to favor any set of specific proportions. It would be really interesting to see the results of a team of research scientists work from the opposite starting point - i.e. "lets desgin a type of lighting that makes all bad looking diamonds look bad." The trouble with such systems is people set out to show that good stones look good, and based on their idea of what looks good as to what they end up with as a lighting scheme.

Rhino, Sergey has discussed an experiment. Line the walls and base of Diamond Dock(r) with white paper, conduct a survey with a big range of diamonds, then line it with black paper, do the same again and finally do the survey with the GIA Gray - have I got it right Sergey?

This would show how the various backgrounds and eye adaption can influence the results.

 

[Serg]

Date: 3/15/2006 4:41:57 PM
Author: Rhino
I appreciate a healthy dose of skepticism and I am a firm believer in putting any technology through rigorous testing, primarily how it corellates to human observation. I am all for that.

My question is simple.

What if you take a pair of comparison stones and observe them for brightness in

a. Standard daylight environments such as outside on a cloudy day.
b. Outside in sunlight but in the shade.
c. Standard overhead office lighting (overhead fluorescents)
d. Diffuse LED''s (as opposed to direct)
e. Then lastly the GIA DiamondDock

and you see the same exact optical phenomena in each and every instance?

Simple answer: Nothing. Such test proof NOTHING.

See non simple answer below:
Even hundreds such pair can not proof anything.
Diamonds can be too close or opposite have big difference which easily can be see in most reasonable light schemes.
Such type tests can not proof what reasonable light scheme is correct for cut grading.

But single pair can proof what light scheme is not correct for cut grading.

Such pair exist for DD GIA.

Sufficient conditions for such pair.
1) First type pair. Diamond A and B are more and less similar( and in same time more and less very good or perfect) in most consumer light conditions. But in DD GIA such diamonds is quite different.
2) Second type pair .Diamond A is much better than Diamond B in most consumer light conditions, But in DD GIA Diamond B is much better than Diamond A

DD GIA can do some diamond do better. For example DD GIA can mask big leakage.
It is right, but it is not big problem for market. If very good or even just good diamond will receive GIA Excellent grade, it is not big problem. Consumer and third party can find special instrument for additional rejections not really nice diamonds from GIA Excellent grade.
DD GIA can do some nice diamond worse or even ugly. This is main problem for market.
Nobody can sell nice diamonds with premium if Diamond has GIA cur grade Good only and in DD GIA this diamond is not nice.
Then you see some diamonds( for examples shallow) in DD GIA a lot of ‘Back rays eye-diamonds’ go between DD GIA visor and your head, In normal consumer light conditions such rays will bring bright( more bright than background ) light from ceiling. But in DD GIA condition ceiling is much more darker than DD GIA background. DD GIA is penalty such diamonds and improve diamonds which rays going in lamps and zone in 10 cm near lamps.
Such work is not correct for cut grading light scheme.

 

[Serg]

re: GH - I tried this and it is true most of the time - but not in a room with suspended lighting, and not in a room with big windows and no lights turned on.


Garry,
1) re:not in a room with big windows .
Correct. But in this case Big windows play role of ceiling.
2) re:no lights turned on.
not interesting example now
I try show common ( main) rule. My task to show main important difference between DD GIA and consumer standard light conditions.
In consumer standard light conditions big part space has brightness much bigger than background. In DD GIA small part space has brightness much bigger than background. It is main my point.

Other is not very important yet.

 

[Serg]

a.In DiamondDock white walls are very close to the bright light source therefore the background is some orders of magnitude brighter than in reality. This causes the main difference between real life environment. Balance between background brightness and more bright light sources in Diamond Dock is incorrect. A few light sources has brightness stronger than background, such light sources cover small part of the upper hemisphere.

GHD and the trays have a very flat matt painted gray surface which is just a little bit darker gray than this gray screen shade on Pricescope. They have not made it too light and reflective.

Garry,

I think trays is not very important for eye adaptation in DD GIA. eye is adopted to wall DD GIA

 

[Garry H (Cut Nut)]

Leonid has kindly published this article http://journal.pricescope.com/Articles/37/1/GIA-Excellent-Cut-Grade-Case-Study.aspx in the journal section.

I had an opportunity to spend some time with some large inventorys of GIA graded diamonds and a Diamond Dock(r) recently.

I found three stones that are relatively comparable in color, clarity and non fluoro, girdle thickness etc with 3 distinct proportion sets.

I studied these in DD and took many photo's.

I hope it can be seen as an honest study and will shed some light (pun).

Meanwhile i have had many discussions with Sergey and Leonid about the issues raised in this thread. Sergey suggested I include this information about the effect of the back ground brightness - I decided not to because it was time to publish now and I still need to get my head fully around Sergey's concepts.

I hope you can follow the article and please ask questions and give opinions.

 

[Serg]

Date: 3/16/2006 7:34:48 AM
Author: Garry H (Cut Nut)
Leonid has kindly published this article http://journal.pricescope.com/Articles/37/1/GIA-Excellent-Cut-Grade-Case-Study.aspx in the journal section.

I had an opportunity to spend some time with some large inventorys of GIA graded diamonds and a Diamond Dock(r) recently.

I found three stones that are relatively comparable in color, clarity and non fluoro, girdle thickness etc with 3 distinct proportion sets.

I studied these in DD and took many photo''s.

I hope it can be seen as an honest study and will shed some light (pun).

Meanwhile i have had many discussions with Sergey and Leonid about the issues raised in this thread. Sergey suggested I include this information about the effect of the back ground brightness - I decided not to because it was time to publish now and I still need to get my head fully around Sergey''s concepts.

I hope you can follow the article and please ask questions and give opinions.

re:I studied these in DD and took many photo''s.

Garry,

Just Mono photos can not be final proof because human vision is stereo.

 

[strmrdr]

tarssarb said:
"then the best cert would be simply a data file of geometry"

hammer hit nail on head :}
Make it a helium slt file please.
I can tell pretty much everything there is too know about a diamonds cut from it using tools available.
Including images modeled after real world light envirements that are near identical to the real photos under those conditions.

That is once I get my windows box back live.
Wish there was a linux version of the software!

 

[strmrdr]

Garry,
"Diamonds were shown in a gray color tray; conventional wisdom suggests the tray should have been black. A set diamond has little or no light entering from under the stone so leakage areas look dark."

The should have been shown mounted, plain and simple.
thata My second biggest problem with the study.

This is my first:
"Most of the observations were made by industry participants: only 7% were ''consumers''"

 

[strmrdr]

White hides girdle detail
Black shows artificial brightness.
Neither are good.
I think the gray is good but why didnt they do mounted?!?

I think stone C looks best as do all the stones againt the black because of the contrast with the background but its an unrealistic look.

 

[strmrdr]

Do you have photos of all 3 like image 6 here?

 

[strmrdr]

Studying diamond viewing positions with an unmounted stone?
The lady atleast is doing a pretty good job of looking at diamonds in a realistic manner.
But most people would have put the diamond in the brighter zone over the table and angled back to the eye.

 

[strmrdr]

"When all three stones are dirty, with the usual grease etc, then the shallow ''Very Good'' stone will look the best of the three."

Was this tested with the 3 stones?
It would have been interesting.
Otherwise ill wait for more facts on the issue.

 

[strmrdr]

kicken image Garry,
Iv been waiting for that kind of comparison:

 

[strmrdr]

Garry,
overall a good article thank you.
While I didn find some points that I question it did give me some good information.
The cz shots are very very interesting.

 

[belle]

really good article garry. what our eyes see about diamonds in real life cannot be replicated in photo''s, but i think one can get a good idea of the differences in brightness and contrast (or the lack thereof) with what you have here. well done.