Enhanced depth of focus is very important to grade Scintillation and table color in Fancy cuts

[Serg]

Samples of videos with enchanted DOF ( standard Dibox2.0 movies are on right side)

Cushion0 high DOF

cutwise.com

Now become possible to grade Scintillation based on real movies . It has to reduce penalty nice fancy cit designs

New Fancy Color

cutwise.com

 

[Karl_K]

kewl, focus stacking?

While I agree they are better the concept of grading scintillation in a meaningful way is not practical in my opinion. You would need to use many different types of lighting with different amounts of obstruction to get a meaningful result.

 

[Rockdiamond]

Great work Serg!!

I have noticed how my camera focuses on "crushed ice" diamonds.....as compared to my eyes.
Part of the "magic" is the lack of ability to get a truly fine focus on the bottom of the diamond through the top....
Maybe this makes no sense...but it seems that when looking at an H&A stone- your eye can focus on the reflections coming off the pavilion, through the table.

With crushed ice, the eye can't find a focal point- and it gets.......crazy.

 

[Serg]

Great work Serg!!

I have noticed how my camera focuses on "crushed ice" diamonds.....as compared to my eyes.
Part of the "magic" is the lack of ability to get a truly fine focus on the bottom of the diamond through the top....
Maybe this makes no sense...but it seems that when looking at an H&A stone- your eye can focus on the reflections coming off the pavilion, through the table.

With crushed ice, the eye can't find a focal point- and it gets.......crazy.

Naked eye has much longer depth of focus than a camera with macro lens.
So when your eye focuses on a girdle you see in focus table , girdle , culet and VF's after 5-20 reflections . it is very important phenomenon for evaluation a fancy cut optical performance that include Brilliancy, Fire , Scintillation , symmetry,..
Without Scintillation input most fancy cuts( specially "crushed ice" designs can not compete with RBC.

 

[oldminer]

Sergey;

What are your thoughts on the size of the scintillations. Older cuts tend to have few, but larger scintillations. Modern cuts, rounds and the non-step cut fancy shapes have numerous, but rather small scintillations. I suppose the point of discussing getting these into focus in order to grade this effect by some algorithm is a useful enterprise in making grading of diamonds more thorough and possibly less subjective. That's the direction most of the business is headed to.

However, some people truly like the distinctive beauty of diamonds with fewer and larger scintillating features. Old cut enthusiasts embrace the bold sparkle of well cut old mine and old Euro cut diamonds. Do you think such stones might also be seen to have successful and excellent cutting when their attractiveness is very high too? There ought to be a category for judging the human attraction level for different looks and approaches to the concept of what is deemed as "finely" cut.

It is somewhat easier to grade down one path of data, but I sure hope due consideration is given to human preferences and the diversity of what is considered as beautiful.

Nice to see you back on Rocky Talky.

 

[Karl_K]

With the changes in indoor lighting to super-flat lighting, even led lights are now very diffused and flat, how do you see this impacting any kind of scintillation testing/grading?

This is related to Dave's question also because what I like to call pattern stones, stones that have distinct bold patterns OEC and similar chunky stones, and step cuts present another area of light performance that is 100% opposite of a crushed ice stone.
The mrb will fall somewhere in between.
How can all these different desirable light behaviors be accounted for and not punish one type unfairly?
The AGS system tries to turn everything into an MRB is clearly not the answer.

 

[lulu_ma]

This is an interesting discussion! Pics and or vids would be helpful to illustrate your points.

 

[Serg]

Dave,

to my understanding Old mine cut has high Brilliancy and Low Scintillation, while Radiant and Princess “Crushed ice “ cuts have high Scintillation and low Brilliancy.
Modern RBC has a good balance between Brilliancy and Scintillation.

Generally, small and “fast“ virtual facets create Scintillation, while Brilliancy mostly depends on big and medium sized “slower" virtual facets .

https://files.octonus.com/documents/GAA_Journal_V25_No3_Sept2013_V5.pdf

“Scintillation in a diamond is observed as quick bright flashes that appear and disappear when a diamond is moved and illumination originates from bright light sources of small angular size. The same effect is observed when an observer or light source changes position relative to a diamond. A scintillation image changes very quickly with minimal gem rocking because of the small angular size of the light sources. Hence scintillation is not a single pattern but rather a dynamic set of flashes. Fast contrast is an important property of scintillation. Here, as in the case of brilliance, all coloured parts of flashes should be regarded as fire rather than scintillation.“

Young people naturally have better ability to distinguish small flashes. I think this is the reason why mature consumers prefer Old mine cuts and emeralds while younger consumers more often select princess cuts, for example ( if we take into account fancy cuts consumers only).

 

[Serg]

This is an interesting discussion! Pics and or vids would be helpful to illustrate your points.

Did you check the links from 1st post?

Cushion0 high DOF

cutwise.com

 

[lulu_ma]

Did you check the links from 1st post?

Cushion0 high DOF

cutwise.com

I did not-but I will!

 

[lulu_ma]

Dave,

to my understanding Old mine cut has high Brilliancy and Low Scintillation, while Radiant and Princess “Crushed ice “ cuts have high Scintillation and low Brilliancy.
Modern RBC has a good balance between Brilliancy and Scintillation.



Young people naturally have better ability to distinguish small flashes. I think this is the reason why mature consumers prefer Old mine cuts and emeralds while younger consumers more often select princess cuts, for example ( if we take into account fancy cuts consumers only).

This diagram is very interesting! As a consumer, I guess I have never been a big fan of scintillation as I chose an emerald cut for my e-ring over 2 decades ago. And now I am an old cut lover.

 

[Garry H (Cut Nut)]

Samples of videos with enchanted ENHANCED DOF ( standard Dibox2.0 movies are on right side)

Cushion0 high DOF

cutwise.com

Now become possible to grade Scintillation based on real movies . It has to reduce penalty nice fancy cit designs

New Fancy Color

cutwise.com

A few comments, having two hours ago sat with a client buying a 3ct cushion. She needed my 2X glasses to understand tiny virtual facets because her sight was not good enough (but she does not wear glasses).
Everyone who wears reading glasses can see much more fire without their glasses on. And this is apparent in both the right side images which do not have the high depth of field.
I feel the high depth of field increases the contrast to a level that is unrealistic for humans - for example the blacks are blacker - too dark infact.
I am not sure the lighting is comparable since the bright reflections in the left high DOF are much brighter than the normal focus. Also perhaps the timing is different? (I feel the left images are virtual in models of the same lighting).