shape
carat
color
clarity

An interesting (to me) ASET comparison -- JA vs. DiamCalc

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

drk14|1410142297|3746758 said:
Karl_K|1410140704|3746746 said:
drk14|1410124540|3746607 said:
Is it safe to say that each spot on the sphere maps to one virtual facet?
No, one VF may draw light from multiple locations
But multiple locations on the sphere suggests that the reverse ray-trace (from the eye through the diamond to the sphere) was bifurcated at some point -- doesn't this imply that the ray has hit a facet boundary (how else would the ray split?), and wouldn't this therefore create two distinct virtual facets for the viewer?

no, one area of the diamond aka VF can draw light from multiple locations because you have a complex arrangement of reflectors feeding any given area of the diamond. You could consider it as multiple vf's overlapping each other with the same exit but different sources.

Karl_K|1410140704|3746746 said:
2 VFs can draw light from the same general location.
OK, but is this just a limitation of the software (or the rendering of the sphere)? That is to say, under this scenario, if we were able to zoom in on such a spot on the surface of the sphere (i.e., "the same general location" that serves as a light source for two distinct VFs), would we then see two distinct spots if the spatial resolution was sufficient?

I would think so but I can not do that with the software I have.


And with regards to wavy facets: Are these accounted for in computer-generated ASETs?
No in general because the scanner will not see them because the do not create an edge the scanner can pick up. I suppose it is possible if it was bad enough that it could but I have doubts.
Static ASET is not likely to pick them up either. With motion you might see something under ASET.
 

drk14

Brilliant_Rock
Joined
Jun 25, 2014
Messages
1,061
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410143006|3746765 said:
no, one area of the diamond aka VF can draw light from multiple locations because you have a complex arrangement of reflectors feeding any given area of the diamond. You could consider it as multiple vf's overlapping each other with the same exit but different sources.
Thanks for clarifying, yes, I forgot that the "reverse" ray can exit the diamond multiple times. :doh: So having realized this, now it seems to me that it would be the norm rather than the exception, that VFs draw light from multiple source directions. However, perhaps it is common that one of these directions is much more dominant than the others?
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

drk14|1410144994|3746784 said:
Karl_K|1410143006|3746765 said:
no, one area of the diamond aka VF can draw light from multiple locations because you have a complex arrangement of reflectors feeding any given area of the diamond. You could consider it as multiple vf's overlapping each other with the same exit but different sources.
Thanks for clarifying, yes, I forgot that the "reverse" ray can exit the diamond multiple times. :doh: So having realized this, now it seems to me that it would be the norm rather than the exception, that VFs draw light from multiple source directions. However, perhaps it is common that one of these directions is much more dominant than the others?
I don't know which is more common, limited tools for now.
I would think that smaller VF's that are a result of more interactions would have more feed points for lack of a better term.
Which would also account for the faster flashes under movement and more flashes than larger VF's in a low contrast environment.
Small and med VF's are much more complex than large VF's because of the increased interactions that create them.


.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410143006|3746765 said:
drk14|1410142297|3746758 said:
Karl_K|1410140704|3746746 said:
drk14|1410124540|3746607 said:
And with regards to wavy facets: Are these accounted for in computer-generated ASETs?
No in general because the scanner will not see them because the do not create an edge the scanner can pick up. I suppose it is possible if it was bad enough that it could but I have doubts.
Static ASET is not likely to pick them up either. With motion you might see something under ASET.

It would be interesting to see comparative images of the sphere of different cut qualities. In particular, two stones with the same overall proportions but with different levels of faceting precision.

DRK, there is another AGS tool that allows you to graphically see the extent of variances of facet angles and azimuths for rounds. It's called the Visual Proportion Analyzer (VPA) and it analyzes the 3D scan. It's available as a free download from AGSL. I would be interested to hear your comments on the tool. It is not referred to on the forum very much, although it seems like it would be of interest to the advanced consumer looking for a precision cut round.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

I am not impressed by vpa I would rather have a list of numbers also depending on the quality of the scan it may or may not mean anything.
Once you move from in general to the specific the need for accurate data goes up a large amount.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

For now I am going to jump to the end of why some scintillation is crisp and some not.
The biggest factor is the quality of the reflectors and how they are aligned.
The tighter and more uniform the area of light sent to the eye from a VF is the more crisp it will appear as it moves across the eye. Find a point where the VF changes intensity and rock back and forth and if its crisp it will be a quick and snappy transition. If the light is not tight or uniform it can appear to flow from one level to the next rather than snap on/off.
Take a mirror and in a dark room shine a flashlight at the mirror and look at the light when it hits the ceiling or wall. At some angles it will be tighter then other and resemble the original source.
now do the same thing with 2 mirrors so the light hits one then the other then the ceiling.
When everything is perfect aligned you will get a crisper and more uniform image on the ceiling.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410191625|3747015 said:
For now I am going to jump to the end of why some scintillation is crisp and some not.
The biggest factor is the quality of the reflectors and how they are aligned.
The tighter and more uniform the area of light sent to the eye from a VF is the more crisp it will appear as it moves across the eye. Find a point where the VF changes intensity and rock back and forth and if its crisp it will be a quick and snappy transition. If the light is not tight or uniform it can appear to flow from one level to the next rather than snap on/off.
Take a mirror and in a dark room shine a flashlight at the mirror and look at the light when it hits the ceiling or wall. At some angles it will be tighter then other and resemble the original source.
now do the same thing with 2 mirrors so the light hits one then the other then the ceiling.
When everything is perfect aligned you will get a crisper and more uniform image on the ceiling.
I think this is an important area of study to emphasize. Most consumers that spend time on this site come to understand that cut quality is the key to diamond performance. And they are therefore looking at info like GIA specs and HCA scores with great enthusiasm. However, it is at a deeper level (where the mirrors all align) that determines if the diamond's full potential for beauty has been unveiled.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer|1410192646|3747031 said:
I think this is an important area of study to emphasize. Most consumers that spend time on this site come to understand that cut quality is the key to diamond performance. And they are therefore looking at info like GIA specs and HCA scores with great enthusiasm. However, it is at a deeper level (where the mirrors all align) that determines if the diamond's full potential for beauty has been unveiled.
I am hesitant to use the word beauty or even quality because we don't know at what point it is good enough to a significant amount of people or bad enough to bother enough people to matter.
Those numbers are not the same.
Getting those numbers would take a big double bind study. Big $$$$$.
Right now all that can be said is it exists.
 

diagem

Ideal_Rock
Trade
Joined
Oct 21, 2004
Messages
5,096
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer|1410186006|3746966 said:
It would be interesting to see comparative images of the sphere of different cut qualities. In particular, two stones with the same overall proportions but with different levels of faceting precision.

From our experience, ETAS is one of the more sensitive tests that show the actual 3D precision of the cut.
It's a physical light test. The more precise the cut, the more uniform ETAS will appear. Of course virtual ETAS is only as precise as the scan representing it.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410204030|3747127 said:
Texas Leaguer|1410192646|3747031 said:
I think this is an important area of study to emphasize. Most consumers that spend time on this site come to understand that cut quality is the key to diamond performance. And they are therefore looking at info like GIA specs and HCA scores with great enthusiasm. However, it is at a deeper level (where the mirrors all align) that determines if the diamond's full potential for beauty has been unveiled.
I am hesitant to use the word beauty or even quality because we don't know at what point it is good enough to a significant amount of people or bad enough to bother enough people to matter.
Those numbers are not the same.
Getting those numbers would take a big double bind study. Big $$$$$.
Right now all that can be said is it exists.
Ha! It is probably wise to limit the use of the "B" word lest someone cries "subjectivity"! I guess my point is that this area of study is important in that what is happening at the virtual facet level has a big impact on how we perceive the diamond. High precision (or lack thereof) can influence light performance in very important ways, even when overall proportions are within ideal ranges.

A given facet design might be great, but it is not optimized unless the craftsman is successful in aligning the all the mirrors precisely in three dimensions. It's kind of like comparing two different cars. One has an engine designed for quick acceleration, the other for efficiency at high speed. You may prefer one type over the other, but both engines have to be properly tuned to deliver the expected performance.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
9,711
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

I think part of what we are discussing here has to do with "Diamond Demographics"
Someone looking for a stone with distinct patterns- such an an RBC, or a stone cut to have a facet pattern similar to an RBC would consider "cut quality" and "light performance" to be different than someone looking for the chaotic scintillation of many and varied VF's.
Put simply,the cutter of a stone with a lot of VF's has so many more options when it comes to facet placement and size. They are selling to people looking for different aspects of beauty than someone looking for what's become known a "light performance".

So, the huge investment required in research for finding ways of quantifying and or repeating a given set of parameters makes a lot less sense.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Now we are starting down that rabbit hole I was talking about earlier.

I have more I would like to discuss like rate of change and separation of scintillation events but like Byran I don't want to get bit by a rabbit and I am claustrophobic so I am not sure.
 

drk14

Brilliant_Rock
Joined
Jun 25, 2014
Messages
1,061
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl,
I appreciate the tutorial so far, and I would love to hear more.

And in the interest of escaping the rabbit hole, allow me to backtrack to the beginning of my thought process when I was originally asking about crisp facets (and the extent to which this quality is captured in computer-generated ASETs).

The explanations so far have been about "crispness" as a dynamic event, i.e., the abruptness of intensity changes observed in virtual facets as the diamond undergoes a small rotation. However, in static images of diamonds, there can also be a marked difference in sharpness of the virtual facets. I'm wondering what explains this, and if it is the same phenomenon as the one you have been describing.

For example, below are two marquise diamonds from JA. The first is mine, and I consider it to have a large percentage of sharp/crisp VFs. The second is an early contender in my diamond search, which I ultimately ruled out because the VFs look so blurry in the photo and video (click the links for 360 video).

hdef_ja_640w.png
Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.05-carat-e-color-si1-clarity-sku-222673

blurry_ja_640w.png
Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.28-carat-d-color-vs2-clarity-sku-348340
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

drk14|1410231318|3747481 said:
Karl,

For example, below are two marquise diamonds from JA. The first is mine, and I consider it to have a large percentage of sharp/crisp VFs. The second is an early contender in my diamond search, which I ultimately ruled out because the VFs look so blurry in the photo and video (click the links for 360 video).

hdef_ja_640w.png
Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.05-carat-e-color-si1-clarity-sku-222673

blurry_ja_640w.png
Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.28-carat-d-color-vs2-clarity-sku-348340
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
I thought you were talking about viewing them in person.
However, when I am talking about, well formed beams of light being sent to the eyes can apply to static viewing, it is far more obvious with movement however.
That isn't what is going on in those pictures however.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

drk14|1410231318|3747481 said:
Karl,
I appreciate the tutorial so far, and I would love to hear more.

And in the interest of escaping the rabbit hole, allow me to backtrack to the beginning of my thought process when I was originally asking about crisp facets (and the extent to which this quality is captured in computer-generated ASETs).

Sarin/DiamCalc ASET:
aset_dc_640w.png
This is an interesting question and one that could help with the overall interpretation of ASET images.

Karl, I presume that where you see colors other than blue, red and green you are seeing evidence of a virtual facet. That is, an overlay for instance of red and blue creating purple. Where is the yellow color coming from in the above image (the original CG ASET that drk posted).
 

drk14

Brilliant_Rock
Joined
Jun 25, 2014
Messages
1,061
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410235968|3747530 said:
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
Thanks, Karl.

I had originally thought this was the reason, and in fact requested from JamesAllen that they take a new, in-focus picture of the second diamond, but they replied that "The movies for each diamond are capturing what was intended and if it looks a little blurry in the video, then it will most likely be that wa[y] in person."

Also, I have seen many a thread here on PS where sales are lost (i.e., candidate diamonds are rejected) based on "blurry" facets in the diamond photos. Assuming no major clarity issues in the diamond, are all of these rejections "false negatives" based on faulty photography?

What about less extreme examples, like the two below, in which the table and pavilion mains appear to be in focus (suggesting camera setup is adequate), but most of the VFs (other than the belly region) are blurry?

Img.Large.Diamond.jpg

Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.01-carat-e-color-vvs1-clarity-sku-207680

Img.Large.Diamond.jpg

Video: http://www.jamesallen.com/loose-diamonds/marquise-cut/1.52-carat-e-color-vs1-clarity-sku-116207
 

drk14

Brilliant_Rock
Joined
Jun 25, 2014
Messages
1,061
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer|1410282226|3747750 said:
Karl, I presume that where you see colors other than blue, red and green you are seeing evidence of a virtual facet.
To clarify: ...evidence of a virtual facet that draws light from multiple directions corresponding to different colored zones in the ASET reflector.

Good observation!
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer|1410282226|3747750 said:
drk14|1410231318|3747481 said:
Karl,
I appreciate the tutorial so far, and I would love to hear more.

And in the interest of escaping the rabbit hole, allow me to backtrack to the beginning of my thought process when I was originally asking about crisp facets (and the extent to which this quality is captured in computer-generated ASETs).

Sarin/DiamCalc ASET:
aset_dc_640w.png
This is an interesting question and one that could help with the overall interpretation of ASET images.

Karl, I presume that where you see colors other than blue, red and green you are seeing evidence of a virtual facet. That is, an overlay for instance of red and blue creating purple. Where is the yellow color coming from in the above image (the original CG ASET that drk posted).
yellow is color mixing, I have never seen it that invidious in a real aset image or ASET in person.
It is more of a DC thing.
Something to keep in mind is that DC ASET with a theoretical perfect diamond scan has higher color resolution than a real image. It also has more VF separation due to depth of field issues with a real image.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

drk14|1410282351|3747753 said:
Karl_K|1410235968|3747530 said:
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
Thanks, Karl.

I had originally thought this was the reason, and in fact requested from JamesAllen that they take a new, in-focus picture of the second diamond, but they replied that "The movies for each diamond are capturing what was intended and if it looks a little blurry in the video, then it will most likely be that wa[y] in person."

Also, I have seen many a thread here on PS where sales are lost (i.e., candidate diamonds are rejected) based on "blurry" facets in the diamond photos. Assuming no major clarity issues in the diamond, are all of these rejections "false negatives" based on faulty photography?

What about less extreme examples, like the two below, in which the table and pavilion mains appear to be in focus (suggesting camera setup is adequate), but most of the VFs (other than the belly region) are blurry?
They are losing some sales if they aren't redoing some of them as there are clear photo related issues with some of them.

If I analyze each diamond someone is going to report it and I will get in trouble.

So im going to give you the info for doing it yourself.
There is what I call mush or areas of ineffective or near infective VFs often combined with leakage.
They look like blurry mush in person and in pictures.
In the JA vids to tell if your seeing mush or blurry photo look at the facet junctions and look for changes in that are as you move from one image to the next if you see fairly clear signs of VF flash even blurry it is likely photo related. Do that for all 4 diamonds you posted and you will see it clearly.
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,620
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410284218|3747784 said:
Texas Leaguer|1410282226|3747750 said:
drk14|1410231318|3747481 said:
Karl,
I appreciate the tutorial so far, and I would love to hear more.

And in the interest of escaping the rabbit hole, allow me to backtrack to the beginning of my thought process when I was originally asking about crisp facets (and the extent to which this quality is captured in computer-generated ASETs).

Sarin/DiamCalc ASET:
aset_dc_640w.png
This is an interesting question and one that could help with the overall interpretation of ASET images.

Karl, I presume that where you see colors other than blue, red and green you are seeing evidence of a virtual facet. That is, an overlay for instance of red and blue creating purple. Where is the yellow color coming from in the above image (the original CG ASET that drk posted).
yellow is color mixing, I have never seen it that invidious in a real aset image or ASET in person.
It is more of a DC thing.
Something to keep in mind is that DC ASET with a theoretical perfect diamond scan has higher color resolution than a real image. It also has more VF separation due to depth of field issues with a real image.

Strange. as I remember it was long discussion on PS about yellow facets in ASET photos and I published AGS ASET photos with such yellow facet, did not I ?
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410285011|3747795 said:
drk14|1410282351|3747753 said:
Karl_K|1410235968|3747530 said:
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
Thanks, Karl.

I had originally thought this was the reason, and in fact requested from JamesAllen that they take a new, in-focus picture of the second diamond, but they replied that "The movies for each diamond are capturing what was intended and if it looks a little blurry in the video, then it will most likely be that wa[y] in person."

Also, I have seen many a thread here on PS where sales are lost (i.e., candidate diamonds are rejected) based on "blurry" facets in the diamond photos. Assuming no major clarity issues in the diamond, are all of these rejections "false negatives" based on faulty photography?

What about less extreme examples, like the two below, in which the table and pavilion mains appear to be in focus (suggesting camera setup is adequate), but most of the VFs (other than the belly region) are blurry?
They are losing some sales if they aren't redoing some of them as there are clear photo related issues with some of them.

If I analyze each diamond someone is going to report it and I will get in trouble.

So im going to give you the info for doing it yourself.
There is what I call mush or areas of ineffective or near infective VFs often combined with leakage.
They look like blurry mush in person and in pictures.
In the JA vids to tell if your seeing mush or blurry photo look at the facet junctions and look for changes in that are as you move from one image to the next if you see fairly clear signs of VF flash even blurry it is likely photo related. Do that for all 4 diamonds you posted and you will see it clearly.
I wonder if there are ASET signatures that would correspond to mush. For example, would you see areas of significant color mixing where virtual facets would be giving chaotic rather than crisp responses?
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,620

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Karl_K|1410284218|3747784 said:
yellow is color mixing, I have never seen it that obvious in a real aset image or ASET in person.
It is more of a DC thing.
Spell check bit me lol
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Serg|1410286523|3747817 said:
https://www.pricescope.com/forum/rockytalky/yellow-in-an-aset-t153335-30.html
PS discussion about Yellow in ASET.
you may find here Rhino example ( real photos of cushion ) and photos from AGS article with yellow ASET zones in Round cut!

http://agslab.com/spie/spie_lo_res.pdf

there are many other strange comments about VF's, ETAS,.. in current discussion
Serg,
I'm not sure what was determined in the referenced thread with regard to yellow color. There is discussion of "mixing" of red and green to make yellow (which does not seem very intuitive to me), there is mention of the contribution of dispersion, and yet other discussion about the body color of the stone being magnified by internal reflection before exiting through the pavilion as leakage.

I also see the yellow shown in the AGS article - in the "actual photo", but not in the CG. Since body color is not a factor in AGS CG ASET, I assume that accounts for why there is yellow in the actual but not the CG. HOWEVER, if you look at the ASET matrices of secondary refraction (figure 25) you do see yellows, and perhaps to a lesser degree in some tilt views. So, is the yellow being modeled by AGS somehow a function of dispersion?
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
9,711
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer said:
Karl_K|1410285011|3747795 said:
drk14|1410282351|3747753 said:
Karl_K|1410235968|3747530 said:
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
Thanks, Karl.

I had originally thought this was the reason, and in fact requested from JamesAllen that they take a new, in-focus picture of the second diamond, but they replied that "The movies for each diamond are capturing what was intended and if it looks a little blurry in the video, then it will most likely be that wa[y] in person."

Also, I have seen many a thread here on PS where sales are lost (i.e., candidate diamonds are rejected) based on "blurry" facets in the diamond photos. Assuming no major clarity issues in the diamond, are all of these rejections "false negatives" based on faulty photography?

What about less extreme examples, like the two below, in which the table and pavilion mains appear to be in focus (suggesting camera setup is adequate), but most of the VFs (other than the belly region) are blurry?
They are losing some sales if they aren't redoing some of them as there are clear photo related issues with some of them.

If I analyze each diamond someone is going to report it and I will get in trouble.

So im going to give you the info for doing it yourself.
There is what I call mush or areas of ineffective or near infective VFs often combined with leakage.
They look like blurry mush in person and in pictures.
In the JA vids to tell if your seeing mush or blurry photo look at the facet junctions and look for changes in that are as you move from one image to the next if you see fairly clear signs of VF flash even blurry it is likely photo related. Do that for all 4 diamonds you posted and you will see it clearly.
I wonder if there are ASET signatures that would correspond to mush. For example, would you see areas of significant color mixing where virtual facets would be giving chaotic rather than crisp responses?


There are ASET signatures that correspond to softer VF's ( I don't love the word "mush") for sure, but they are not consistent. I have looked at a lot of Fancy Colored Stones in ASET trying to find consistency of face up compared to ASET. It's often hard to draw comparisons.
About what the JA rep wrote- I agree.
The type of stone that has this "chaotic" type of sparkle looks that way because the eye can not focus on the pavilion of the diamond, as one might on an RBC.
A marquise may offer a blend of both.
A human may be able to focus on the pavilion at the center, but not at the tips.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,760
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Rockdiamond|1410295678|3747948 said:
Texas Leaguer said:
Karl_K|1410285011|3747795 said:
drk14|1410282351|3747753 said:
Karl_K|1410235968|3747530 said:
Simple one is out of focus and one is better focused.
That is a camera problem more than a diamond problem.
Thanks, Karl.

I had originally thought this was the reason, and in fact requested from JamesAllen that they take a new, in-focus picture of the second diamond, but they replied that "The movies for each diamond are capturing what was intended and if it looks a little blurry in the video, then it will most likely be that wa[y] in person."

Also, I have seen many a thread here on PS where sales are lost (i.e., candidate diamonds are rejected) based on "blurry" facets in the diamond photos. Assuming no major clarity issues in the diamond, are all of these rejections "false negatives" based on faulty photography?

What about less extreme examples, like the two below, in which the table and pavilion mains appear to be in focus (suggesting camera setup is adequate), but most of the VFs (other than the belly region) are blurry?
They are losing some sales if they aren't redoing some of them as there are clear photo related issues with some of them.

If I analyze each diamond someone is going to report it and I will get in trouble.

So im going to give you the info for doing it yourself.
There is what I call mush or areas of ineffective or near infective VFs often combined with leakage.
They look like blurry mush in person and in pictures.
In the JA vids to tell if your seeing mush or blurry photo look at the facet junctions and look for changes in that are as you move from one image to the next if you see fairly clear signs of VF flash even blurry it is likely photo related. Do that for all 4 diamonds you posted and you will see it clearly.
I wonder if there are ASET signatures that would correspond to mush. For example, would you see areas of significant color mixing where virtual facets would be giving chaotic rather than crisp responses?


There are ASET signatures that correspond to softer VF's ( I don't love the word "mush") for sure, but they are not consistent. I have looked at a lot of Fancy Colored Stones in ASET trying to find consistency of face up compared to ASET. It's often hard to draw comparisons.
About what the JA rep wrote- I agree.
The type of stone that has this "chaotic" type of sparkle looks that way because the eye can not focus on the pavilion of the diamond, as one might on an RBC.
A marquise may offer a blend of both.
A human may be able to focus on the pavilion at the center, but not at the tips.
I would expect the ASET signatures of most Fancy Color Stones to be quite distinct from those of diamonds in the normal range as the cutter's goal with a fancy color is significantly different and to some extent contradictory to the goals of cutting a normal color.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
9,711
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Great and oft repeated point Bryan.
I understand some of what the cutters do to increase perceived color. One technique lessens contrast in FCD's , for example.

But in practical terms- I don't see a lot of difference between some well cut "pinfire" cushions of D color, versus another that might be Fancy Vivid.
The real world light performance may be very similar. Lack of contrast can really help in the type of scintillation we're talking about in both Fancy Colored, as well as colorless.

For example I have seen some remarkable Pear Modified Brilliant designs for colorless diamonds that borrow heavily from FCD design.
Less contrast diminishes any sort of "bow tie" for example.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
18,423
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

I am late to the party.
Dave's ASET DiamCalc photo seems to have dispersion on - I like to turn it off.
The DiBox ASET has a slightly larger (black) hole to enable photography than the DC version.
The DC version was modeled largely on my old Hand Held ASET.
I have released a new hand held (which AGS install in their demo version) last year, which is as close as possible to the DiBox model.
 

drk14

Brilliant_Rock
Joined
Jun 25, 2014
Messages
1,061
Re: An interesting (to me) ASET comparison -- JA vs. DiamCal

Texas Leaguer|1410286360|3747813 said:
Karl_K|1410285011|3747795 said:
There is what I call mush or areas of ineffective or near infective VFs often combined with leakage.
They look like blurry mush in person and in pictures.
In the JA vids to tell if your seeing mush or blurry photo look at the facet junctions and look for changes in that are as you move from one image to the next if you see fairly clear signs of VF flash even blurry it is likely photo related. Do that for all 4 diamonds you posted and you will see it clearly.
I wonder if there are ASET signatures that would correspond to mush. For example, would you see areas of significant color mixing where virtual facets would be giving chaotic rather than crisp responses?

This gets to the gist of my original question. I was hesitant to use the word "mush", but in hindsight maybe I should have. :)) So, my proposition was that the DC ASET may be more representative of a non-mushy diamond (like mine), but that it may not accurately convey the IRL impression of a mushy diamond (because the computer-generated VFs are all "sharp"). Although as Bryan noted, perhaps there are tell-tale "signatures" in the DC ASET that can be "interpreted" as mush?
 
Be a part of the community Get 3 HCA Results
Top