Brilliance, Fire, Scintillation, what are correct definitions?

[Garry H (Cut Nut)]

Date: 5/7/2010 9:42:30 PM
Author: Karl_K

Date: 5/7/2010 9:24:10 PM
Author: Garry H (Cut Nut)
I think the answers are clear above? And added too by Sergey''s response to Rhino?

Garry what does brightness have to do with it?
The main reason there would be flashes is that it is not a flat lighting environment.
The lighting would also be off axis which can create fire. (light hitting at an angle is more likely to be returned as fire)
Flat on axis lighting is what will produce little dynamic brightness or dynamic fire.
I am confused and I thought I was starting to follow what Serg was talking about.

exactly

 

[Serg]

approach from observer side for Whom who love word "Contrast

Brilliance- Slow( but not low) Contrast from point to point, from time to time. because changing are slow enough, human brain see it as united image with higher level dynamical brightness range.( Zero speed contrast is contrast fro static image)

Scintillation- is Fast Contrast.( Time to Time) image changing dramatically in very short time. In one time flashes are in one place, in second time other flashes are in quite other place. Changing so fast what human brain can not see it as united image. It is stochastic process for human brain

Fire- Simultaneously( locally) Contrast. Human brain see Hight contrast image in Same POINT( Space) AND in Same Time. ( Take RGB channels is software as Adobe or Corel for photos, and see 3 R, G, B images in same time for photo with fire

So diamond is instrument what create 3 TYPES Contrast for Human Brain

 

[Garry H (Cut Nut)]

Date: 5/8/2010 4:04:17 AM
Author: Serg
approach from observer side for Whom who love word ''Contrast

Brilliance- Slow( but not low) Contrast from point to point, from time to time. because changing are slow enough, human brain see it as united image with higher level dynamical brightness range.( Zero speed contrast is contrast fro static image)

Scintillation- is Fast Contrast.( Time to Time) image changing dramatically in very short time. In one time flashes are in one place, in second time other flashes are in quite other place. Changing so fast what human brain can not see it as united image. It is stochastic process for human brain

Fire- Simultaneously( locally) Contrast. Human brain see Hight contrast image in Same POINT( Space) AND in Same Time. ( Take RGB channels is software as Adobe or Corel for photos, and see 3 R, G, B images in same time for photo with fire

So diamond is instrument what create 3 TYPES Contrast for Human Brain

I have tried to improve Sergey’s English, but have possibly introduced some erros?

Diamond is an instrument that create 3 TYPES Contrast for Human Brain:
An approach from an observer point of view for those who love the concept: "Contrast” (as a diamond is moving relative to a viewer).

1. Brilliance- the human brain sees the diamond as having a higher level of dynamic brightness, but as a united image throughout a range of motion. Contrast is slow (but need not be low) from point to point, from time to time. The changes are slow enough that there never appears to be flashes dancing (If the diamond appeared exactly the same as it moved, like a static image, then it would have Zero dynamic contrast).

2. Scintillation- is Fast Contrast.(from Time to Time) the image is changing dramatically in a very short time. In one time flashes are in one place, in second time other flashes are in another very different place. The changing is so fast that the human brain cannot see it as united image. It is stochastic process for human brain.
Sergey studied a big book on human vision several years ago (we drove Italy to Belguim and I ''got'' about 10% of it - here is some info that might be relevant:
http://en.wikipedia.org/wiki/Flash_suppression
http://en.wikipedia.org/wiki/Binocular_rivalry
http://en.wikipedia.org/wiki/Fixation_%28visual%29
http://en.wikipedia.org/wiki/Eye_movement_%28sensory%29
try the following experiment: hold your hand up, about one foot (30 cm) in front of your nose. Keep your head still, and shake your hand from side to side, slowly at first, and then faster and faster. At first you will be able to see your fingers quite clearly. But as the frequency of shaking passes about 1 Hz, the fingers will become a blur. Now, keep your hand still, and shake your head (up and down or left and right). No matter how fast you shake your head, the image of your fingers remains clear. This demonstrates that the brain can move the eyes opposite to head motion much better than it can follow, or pursue, a hand movement. When your pursuit system fails to keep up with the moving hand, images slip on the retina and you see a blurred hand.
http://en.wikipedia.org/wiki/Smooth_pursuit
That one explains something I have observed – people are more attracted to diamonds rocking back and forward, than left to right. And away, rather than towards:- It’s evolutionary:
“Smooth pursuit is asymmetric: most humans and primates tend to be better at horizontal than vertical smooth pursuit, as defined by their ability to pursue smoothly without making catch-up saccades. Most humans are also better at downward than upward pursuit[1]. Pursuit is modified by ongoing visual feedback.”
http://en.wikipedia.org/wiki/Ocular_microtremor
3. Fire- Simultaneously (locally) Contrast. Human brain see High contrast image in Same POINT (Space) AND in Same Time. (Take RGB channels is software as Adobe or Corel for photos, and see 3 R, G, B images in same time for photo with fire
Help please Sergey??????
So diamond is instrument what create 3 TYPES Contrast for Human Brain

 

[Serg]

Hi Garry,
Thanks for help

re:3. Fire- Simultaneously (locally) Contrast. Human brain see High contrast image in Same POINT (Space) AND in Same Time. (Take RGB channels is software as Adobe or Corel for photos, and see 3 R, G, B images in same time for photo with fire
Help please Sergey??????

Is below image helpful ?

 

[oldminer]

Is Serg attempting to state that the only meaningful definitions of Light Performance refer to diamonds in motion?" Must they be observed and/or measured through analysis of motion videos? Or, are only the definitions all tied to motion while the measures are taken on static frames derived from these motion videos? If the latter is true, then static images are required and motion video is not required. Please clarify as best as possible.

So far, the inability to define the basic vocabulary clearly limits further discussion and understanding for many readers. Or, maybe I am alone in my inability to figure out what is being said. DUH!

 

[Serg]

Date: 5/8/2010 10:08:29 AM
Author: oldminer
Is Serg attempting to state that the only meaningful definitions of Light Performance refer to diamonds in motion?' Must they be observed and/or measured through analysis of motion videos? Or, are only the definitions all tied to motion while the measures are taken on static frames derived from these motion videos? If the latter is true, then static images are required and motion video is not required. Please clarify as best as possible.


So far, the inability to define the basic vocabulary clearly limits further discussion and understanding for many readers. Or, maybe I am alone in my inability to figure out what is being said. DUH!

Dave,
First of all I did not even try develop definitions for measurement tasks. My task is to receive correct and clear definitions.
I sure what main reason why LABs suffered a defeat in cut grading issue what they did not define phenomenas correctly before they become measure its and grade its
They firstly measured something and then define its as Brilliance, Fire, Scintillation. It was main and huge mistake and reason for fall in cut grading issue

 

[Karl_K]

Date: 5/8/2010 10:19:53 AM
Author: Serg

Date: 5/8/2010 10:08:29 AM

Author: oldminer

Is Serg attempting to state that the only meaningful definitions of Light Performance refer to diamonds in motion?'' Must they be observed and/or measured through analysis of motion videos? Or, are only the definitions all tied to motion while the measures are taken on static frames derived from these motion videos? If the latter is true, then static images are required and motion video is not required. Please clarify as best as possible.



So far, the inability to define the basic vocabulary clearly limits further discussion and understanding for many readers. Or, maybe I am alone in my inability to figure out what is being said. DUH!

Dave,

First of all I did not even try develop definitions for measurement tasks. My task is to receive correct and clear definitions.

I sure what main reason why LABs suffered a defeat in cut grading issue what they did not define phenomenas correctly before they become measure its and grade its

They firstly measured something and then define its as Brilliance, Fire, Scintillation. It was main and huge mistake and reason for fall in cut grading issue

Serg, I think the fundamental error may not be so much in those terms but in how they define contrast.
Without a proper definition and understanding of contrast one can not properly define Brilliance, Fire or Scintillation.
For example ASET only accounts for 2 types of contrast, static leakage and static obstruction.
It leaves out the largest one of them all, dynamic phase based contrast.
Which I define as: virtual facets being out of phase with each other as a diamond/light is moved creating contrast. When one is lit another is dark then as the diamond/light moves they change one goes dark the other light back and forth.
Without it you can not properly define Brilliance, Fire or Scintillation.

I think it should really be defined as light moving because even if the diamond is moving, it is the movement relative to the light that is important.

 

[Serg]

Date: 5/8/2010 11:24:09 AM
Author: Karl_K

Date: 5/8/2010 10:19:53 AM

Author: Serg

Date: 5/8/2010 10:08:29 AM


Author: oldminer


Is Serg attempting to state that the only meaningful definitions of Light Performance refer to diamonds in motion?' Must they be observed and/or measured through analysis of motion videos? Or, are only the definitions all tied to motion while the measures are taken on static frames derived from these motion videos? If the latter is true, then static images are required and motion video is not required. Please clarify as best as possible.




So far, the inability to define the basic vocabulary clearly limits further discussion and understanding for many readers. Or, maybe I am alone in my inability to figure out what is being said. DUH!

Dave,


First of all I did not even try develop definitions for measurement tasks. My task is to receive correct and clear definitions.


I sure what main reason why LABs suffered a defeat in cut grading issue what they did not define phenomenas correctly before they become measure its and grade its


They firstly measured something and then define its as Brilliance, Fire, Scintillation. It was main and huge mistake and reason for fall in cut grading issue

Serg, I think the fundamental error may not be so much in those terms but in how they define contrast.

Without a proper definition and understanding of contrast one can not properly define Brilliance, Fire or Scintillation.

For example ASET only accounts for 2 types of contrast, static leakage and static obstruction.

It leaves out the largest one of them all, dynamic phase based contrast.

Which I define as: virtual facets being out of phase with each other as a diamond/light is moved creating contrast. When one is lit another is dark then as the diamond/light moves they change one goes dark the other light back and forth.

Without it you can not properly define Brilliance, Fire or Scintillation.


I think it should really be defined as light moving because even if the diamond is moving, it is the movement relative to the light that is important.

Karl,

re:"I think the fundamental error may not be so much in those terms but in how they define contrast.
Without a proper definition and understanding of contrast one can not properly define Brilliance, Fire or Scintillation."

this your statement mean what they did not define properly Brilliance, Fire and Scintillation.

re:For example ASET only accounts for 2 types of contrast, static leakage and static obstruction.

Lets change it to "For example ASET only accounts 2 reasons for contrast: static leakage and static obstruction."

re:"virtual facets being out of phase with each other as a diamond/light is moved creating contrast. When one is lit another is dark then as the diamond/light moves they change one goes dark the other light back and forth."

In other words: VFs next to each other scan light source space in different directions.
I doubt what we can use combination from words "Virtual facets" and "Out of( in) phase

but again : it is not definition for contrast, it is explanation the reason for contrast in diamond

 

[Karl_K]

Serg,
Yes i believe that current definitions of Brilliance, Fire and Scintillation are lacking.
I wont go as far as to say they are false but they could be a much better match to the real world.

"it is not definition for contrast"(in diamonds)", it is explanation the reason for contrast in diamond"
Pretty much the same thing to me.

I like the term phase based contrast but my training is in eet so in and out of phase makes perfect sense to me.

 

[Paul-Antwerp]

So, according to Sergey''s attempts at definitions, am I understanding the following correctly?

- In an igloo, one can observe brilliance, but not scintillation.
- In an igloo, one can observe fire.
- Even in a light-environment with various sources of indirect light and no direct light-source, one can observe brilliance, scintillation and fire at the same time.

Live long,

 

[Serg]

Date: 5/10/2010 10:09:40 AM
Author: Paul-Antwerp
So, according to Sergey's attempts at definitions, am I understanding the following correctly?


- In an igloo, one can observe brilliance, but not scintillation.

- In an igloo, one can observe fire.

- Even in a light-environment with various sources of indirect light and no direct light-source, one can observe brilliance, scintillation and fire at the same time.


Live long,

Is window in cloudless day indirect light source? I think such light source is primary( and direct) light source for observer conditions in a room.

Fire could be have more than 1 type ( similar different as between Brilliance and Scintillation )

 

[Paul-Antwerp]

I am talking about a window on a cloudy day, not cloudless.

 

[Serg]

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

Just to show difference in illuminance between office light and daylight(skylight)even in cloudy day

 

[Paul-Antwerp]

Are you saying that at a certain level of lux, somewhere between 500 and 1,000, one should start talking about direct light above that level?

Live long,

 

[Serg]

Date: 5/10/2010 2:56:37 PM
Author: Paul-Antwerp
Are you saying that at a certain level of lux, somewhere between 500 and 1,000, one should start talking about direct light above that level?


Live long,

I do not use "direct" and "indirect" light definitions . I use "Primary" and "secondary" lights.

Primary lights have much bigger brightness and much less( usually) total angular size than Secondary lights

absolute level of brightness is not important. ratios are important between primary and secondary light( ratio in brightness and ratio in angular sizes )

 

[oldminer]

Serg;

With all the complexity you assert is necessary for diamond lighting environments, can you propose a "normal", scientifically speaking, standardized lighting environment that would be useful and proper for comparison grading of diamonds? Or, are you saying that the complexity prevents such a definition for the trade to adopt?

It would be more useful to have a standardized environment defined rather than by-passing it by a general discussion of lighting. ImaGem believes they have a sufficient normal, standardized environment which works and you don''t agree although I don''t know how closely you ever investigated their products. Your approach sounds far more intricate and everyone reading this thread has to be curious what model you might propose. It must be a practical model that will serve the end user and the scientists together. It can''t be one which only PHD''s can grasp or use.

 

[Serg]

Date: 5/10/2010 3:27:05 PM
Author: oldminer
Serg;


With all the complexity you assert is necessary for diamond lighting environments, can you propose a 'normal', scientifically speaking, standardized lighting environment that would be useful and proper for comparison grading of diamonds? Or, are you saying that the complexity prevents such a definition for the trade to adopt?


It would be more useful to have a standardized environment defined rather than by-passing it by a general discussion of lighting. ImaGem believes they have a sufficient normal, standardized environment which works and you don't agree although I don't know how closely you ever investigated their products. Your approach sounds far more intricate and everyone reading this thread has to be curious what model you might propose. It must be a practical model that will serve the end user and the scientists together. It can't be one which only PHD's can grasp or use.

Dave,

We( OctoNus, Lexus, Garry) are developing Lbox for diamond comparison and jewelry presentations ( by movies).
Even current version Lbox uses different type illuminations( I do not believe what Light standard could have only ONE illumination) .
http://www.lexus-com.com/lexusnew/product/productd/grading/lightbox.htm
We are trying develop "Open" system where you could use our default illuminations And use own illumination models.
System is simple but You can model diffuse , primary and secondary light illuminations in different combinations .
what is very important we use big angular space to model illumination

It is difficult for me to explain LBox in post, please talk with Garry

Ps/ LBox has not "deep science " and have a lot of direction for improvements ( for example in color light temperature )
it is just practical equipment for diamond comparison when you need receive photos for different diamonds in same positions( same light conditions) and you need tilt diamonds.
without special equipment's you can not do it. Firstly we did it for our internal tasks( NextDiamond and CutStudy)

 

[Garry H (Cut Nut)]

Date: 5/10/2010 4:08:29 PM
Author: Serg

Date: 5/10/2010 3:27:05 PM
Author: oldminer
Serg;


With all the complexity you assert is necessary for diamond lighting environments, can you propose a ''normal'', scientifically speaking, standardized lighting environment that would be useful and proper for comparison grading of diamonds? Or, are you saying that the complexity prevents such a definition for the trade to adopt?


It would be more useful to have a standardized environment defined rather than by-passing it by a general discussion of lighting. ImaGem believes they have a sufficient normal, standardized environment which works and you don''t agree although I don''t know how closely you ever investigated their products. Your approach sounds far more intricate and everyone reading this thread has to be curious what model you might propose. It must be a practical model that will serve the end user and the scientists together. It can''t be one which only PHD''s can grasp or use.

Dave,

We( OctoNus, Lexus, Garry) are developing Lbox for diamond comparison and jewelry presentations ( by movies).
Even current version Lbox uses different type illuminations( I do not believe what Light standard could have only ONE illumination) .
http://www.lexus-com.com/lexusnew/product/productd/grading/lightbox.htm
We are trying develop ''Open'' system where you could use our default illuminations And use own illumination models.
System is simple but You can model diffuse , primary and secondary light illuminations in different combinations .
what is very important we use big angular space to model illumination

It is difficult for me to explain LBox in post, please talk with Garry

Ps/ LBox has not ''deep science '' and have a lot of direction for improvements ( for example in color light temperature )
it is just practical equipment for diamond comparison when you need receive photos for different diamonds in same positions( same light conditions) and you need tilt diamonds.
without special equipment''s you can not do it. Firstly we did it for our internal tasks( NextDiamond and CutStudy)

This is what not to do:
https://www.pricescope.com/community/threads/gia-diamond-dock-simple-summary.42538/
Just read the first post - no need to go to the links.
GIA used light sources that only worked for some cuts, with much too small an angular source area. The light source makes well cut stones appear to have a darker body color than badly cut stones.

We use various diffuser plates as well as my new patented jewelry store lighting concept, and mirrored walls with options for whole mirror or patterns like windows etc. We are experimenting using a photo of ''Jess'' - the same observer as the default HDR environment in DiamCalc.

 

[Paul-Antwerp]

Date: 5/10/2010 3:02:38 PM
Author: Serg

Date: 5/10/2010 2:56:37 PM
Author: Paul-Antwerp
Are you saying that at a certain level of lux, somewhere between 500 and 1,000, one should start talking about direct light above that level?

Live long,

I do not use ''direct'' and ''indirect'' light definitions . I use ''Primary'' and ''secondary'' lights.

Primary lights have much bigger brightness and much less( usually) total angular size than Secondary lights

absolute level of brightness is not important. ratios are important between primary and secondary light( ratio in brightness and ratio in angular sizes )

So, in an office-environment, with the lights out and a north facing window on a cloudy day, the window is the primary light-source, causing the observation of scintillation? As opposed to an igloo, with only secondary light-sources, and thus only the observation of brilliance?

While in a candle-lit restaurant, the candles are the primary light-sources, causing the observation of scintillation and fire?

Live long,

 

[Serg]

Date: 5/11/2010 6:35:24 AM
Author: Paul-Antwerp

Date: 5/10/2010 3:02:38 PM

Author: Serg

Date: 5/10/2010 2:56:37 PM

Author: Paul-Antwerp

Are you saying that at a certain level of lux, somewhere between 500 and 1,000, one should start talking about direct light above that level?


Live long,

I do not use ''direct'' and ''indirect'' light definitions . I use ''Primary'' and ''secondary'' lights.


Primary lights have much bigger brightness and much less( usually) total angular size than Secondary lights


absolute level of brightness is not important. ratios are important between primary and secondary light( ratio in brightness and ratio in angular sizes )

So, in an office-environment, with the lights out and a north facing window on a cloudy day, the window is the primary light-source, causing the observation of scintillation? As opposed to an igloo, with only secondary light-sources, and thus only the observation of brilliance?


While in a candle-lit restaurant, the candles are the primary light-sources, causing the observation of scintillation and fire?


Live long,

Yes, yes, yes.

 

[oldminer]

I can appreciate your creation of a vastly improved light box for viewing and comparing diamonds. This will be a welcome accessory at the sales floor and for the Internet vendor. Now I see where we differ in that my interest is in "grading" and the thrust of what your group is creating has more to do with "displaying" and "viewing". While not mutually exclusive, grading can be quite different than viewing.

Grading needs to use simplicty and repeatability and does not by necessity need to incude a myriad of complexity or many variable lighting models. Observing and comparing diamonds visually in order to select a diamond which an individual likes the best can be a lot more variable in nature.

That''s why I suppose we see the problem so differently as we have somewhat different concepts of why we are doing the things we are involved in with diamond appearance and light return. It all makes much more sense now.

 

[Paul-Antwerp]

Since the specific ''performance'' of a diamond is light-source-dependent (and also observer-dependent), a standardized light-environment can never be the solution to "grade" a diamond.

The cause of "displaying" or "viewing" a diamond could possibly be obtained with a lightbox, especially if it is constructed in a smart way and used for real-life-observations. I think that turning these observations into videos will cause a major loss of information with the camera not being the same as human eyes, the pictured diamond being a lot bigger and the 2D-rendering.

Live long,

 

[Serg]

Date: 5/11/2010 10:12:04 AM
Author: oldminer
I can appreciate your creation of a vastly improved light box for viewing and comparing diamonds. This will be a welcome accessory at the sales floor and for the Internet vendor. Now I see where we differ in that my interest is in ''grading'' and the thrust of what your group is creating has more to do with ''displaying'' and ''viewing''. While not mutually exclusive, grading can be quite different than viewing.


Grading needs to use simplicty and repeatability and does not by necessity need to incude a myriad of complexity or many variable lighting models. Observing and comparing diamonds visually in order to select a diamond which an individual likes the best can be a lot more variable in nature.


That''s why I suppose we see the problem so differently as we have somewhat different concepts of why we are doing the things we are involved in with diamond appearance and light return. It all makes much more sense now.

Dave,
I am understanding how is important grading task. But before anybody could give CORRECT grading diamond performance he needs learn to "viewing" diamonds.
"displaying and Viewing" is first necessary step in R*D work for cut grading.
OctoNus has ability develop cut grading system better then AGS cut grading system much early than AGS did it. I rejected such opportunity because we had not instruments to check our metrics in scientific proof basis. ( AGS had not it too and did not necessary tests. GIA tried do it but again they had not good instruments to do it correctly. I did not see any Imagem tests, BS tests. NOTHING!)

I am working on cut SCORE system several years. We develop cut, then produce diamonds, then compare is, then change metrics. and repeat it several time. to increase repeatability in such tests and create ability to tests our results in different places in same time, we have developed new version Lbox.( first attempt I did in 2000 year! see pictures for study fire from this systemhttp://www.gemology.ru/cut/english/grading1/5.htm )

then we found what it could be interesting for visual comparison

Score system( not penalty grading system) is our final goal. We just want do it in right and scientific base.
Our task to develop Score system what can compare different cuts and help develop cuts much better than round cut with account Human Taste and physiological difference between people
I do not like develop just one more gimmick sales tool.

 

[Serg]

Date: 5/11/2010 10:38:05 AM
Author: Paul-Antwerp
Since the specific ''performance'' of a diamond is light-source-dependent (and also observer-dependent), a standardized light-environment can never be the solution to ''grade'' a diamond.


The cause of ''displaying'' or ''viewing'' a diamond could possibly be obtained with a lightbox, especially if it is constructed in a smart way and used for real-life-observations. I think that turning these observations into videos will cause a major loss of information with the camera not being the same as human eyes, the pictured diamond being a lot bigger and the 2D-rendering.


Live long,

Paul ,

re:into videos will cause a major loss of information with the camera not being the same as human eyes,

Agree when you speak about standard video
I am advice you to wait HDR Stereo version Lbox and then decide

 

[Souled In]

Grading is based on rarity, not visual appeal right?

So a less than ideal cut, with a higher fire rating than most diamonds, would be considered more rare.

It should then be valued higher, until more rares are created, making it less rare.

The only thing else you can do besides rarity, is grade based on difficulty in creating the diamond.

Hence hearts and arrows?

I''m just throwing out half *ssed thoughts to provoke more discussion. Don''t feel obligated to instruct me in the basics which I can study on my own, but feel free if you like, if I did say anything completely insulting or wrong that is.

 

[Garry H (Cut Nut)]

Date: 5/16/2010 8:44:33 PM
Author: Souled In
Grading is based on rarity, not visual appeal right?

So a less than ideal cut, with a higher fire rating than most diamonds, would be considered more rare.

It should then be valued higher, until more rares are created, making it less rare.

The only thing else you can do besides rarity, is grade based on difficulty in creating the diamond.

Hence hearts and arrows?

I''m just throwing out half *ssed thoughts to provoke more discussion. Don''t feel obligated to instruct me in the basics which I can study on my own, but feel free if you like, if I did say anything completely insulting or wrong that is.

I have some rather rare milky white diamonds, and some natural untreated black diamonds. They are not very expensive.
Appeal is also important