Friendly discussion about bottomless buckets of dazzling ice

[drk14]

Rockdiamond/David,
I'm starting a new thread because our discussion got derailed in the other thread. Hope you will see this and don't mind participating.

To set the tone for this thread: As a scientist, I'm looking for the truth. I am interested in David's opinions because he has a perspective that differs from the conventional wisdom on PS. So I hope this conversation will not devolve into anything negative. I would just like to get a better understanding of his views on the type of fancy cut diamonds that he has characterized as appearing like a "bottomless bucket" of "dazzling ice", but that PSers tend to describe using the "M" word that I won't use here (at least not this early in the thread ) out of respect for David.

Such diamond cuts have also been praised by other, less "controversial" PS trade members, and are in my opinion subject of significant confusion on PS:

HOWEVER!!!!!!!!!!!!!!!!!!! When I look at the stone with my eyes it that same delicious crushed ice sparkle that I love when I see a well cut radiant. The stone is GLORIOUS! It's ASET hurts my eyes.

Sigh. SO MUCH to learn!

I sincerely hope that people can refrain from digs or attacks (veiled or otherwise) if they disagree with any of David's statements. Like I said, I think his experience and opinions are valuable, and the purpose of this thread is to allow me (and others) to get a better picture of his perspective.

David:
I think that we did agree in the other thread that within the universe of diamonds that appear to be non-crisp and/or have washed-out areas in ASETs, some stones may be poorly cut, while some stones may manifest as a "bottomless bucket" of "dazzling ice".

Some of your comments also suggest that you can see the potential in some of these diamond photos and videos that would be disparaged by most PS members. Is this true -- can you tell a badly cut diamond from a non-crisp "dazzling ice" diamond by looking at photos and videos? If so, what do you look for? What are the signs that suggest to you that the diamond will be found attractive by someone who appreciates the "bottomless bucket" effect?

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

Hi Drk!!

Awesome thread!!

I will definitely be participating.
I can't tell you how much I appreciate your willingness to discuss this important subject in a neutral manner.
It may take till Monday for me to respond thoroughly and I will for sure.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

Great, I look forward to seeing your comments.

 

[pyramid]

Re: Friendly discussion about bottomless buckets of dazzling

I am also interested in reading this topic.

 

[arkieb1]

Re: Friendly discussion about bottomless buckets of dazzling

People on here knock and criticise most crushed ice stones. The simple truth is some (and I say some meaning not all but a few if you look carefully) look like wonderful disco ball diamonds which are actually very attractive to many people.

 

[hiratop]

Re: Friendly discussion about bottomless buckets of dazzling

I find a well done fancy colour crushed ice radiant one of the most attractive type of diamonds there is. But they are rare.

 

[chrono]

Re: Friendly discussion about bottomless buckets of dazzling

I thought we had a similar topic where the crushed type radiants were discussed, complete with ASET pictures posted?

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

First aspect that bears closer discussion:
Precision
With a stone which is cut for optical symmetry, it's fairly clear if the cutter was successful.
This makes reading ASET and other such tools far more straightforward.
When cutting for a pattern, making sure everything lines up exactly is crucial.
Not so with "crushed Ice". Sometimes a stone that has some asymmetry in the facet design looses nothing in the actual appearance.
Part of what makes the "crushed ice" look so amazing is that the light is bouncing around in ways that are kind of "chaotic"
We need this sort of "light chaos" so that the stereoscopic viewer ( your eyes ) perceive the sparkle.

Below are two photos of the same stone, taken in a light box.
The "Sharp" picture shows the actual facet pattern of the pavilion coming through the table.\
In the "Soft" picture the camera is focusing at a slightly different spot on the stone- more like what our eyes do.
All of a sudden the sharply defined facets seem to blur together. This is part of how we perceive "crushed ice"





Part of why this is far more difficult to plot out with ASET is because the diamond is using the light in a totally different manner.

 

[chrono]

Re: Friendly discussion about bottomless buckets of dazzling

David,
The radiant you posted (just above) shows a lovely symmetrical pattern which I think even the crushed ice nay-sayers will find attractive. I think that one will ASET well. Does it? It's a coloured diamond and is cut to retain colour so such comparison may not be fair?

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

Hi Chrono,

Thanks for participating!
I think that frequently, when this subject has been discussed, there were negative aspects that detracted from the discussion.
DRK has phrased this in a manner that hopefully, will produce different results.

David,
The radiant you posted (just above) shows a lovely symmetrical pattern which I think even the crushed ice nay-sayers will find attractive. I think that one will ASET well. Does it? It's a coloured diamond and is cut to retain colour so such comparison may not be fair?

The diamond in the pics is gone- so I can't take an ASET pic.

To your second point: Personally I find greater similarities between nice colorless "crushed ice" stones and FCD's as opposed to differences.
When I speak with cutters, they point out the differences- but speaking from the experience looking at the stones, collorless and FCD share a lot

 

[Texas Leaguer]

Re: Friendly discussion about bottomless buckets of dazzling

I thought we had a similar topic where the crushed type radiants were discussed, complete with ASET pictures posted?

Chrono, I think this may be the thread you are referring to. It was a very long thread that eventually went off the tracks. It might be worthwhile to review in hopes that some of the same pitfalls can be avoided here.

[URL='https://www.pricescope.com/community/threads/radiant-diamond-cut-evaluation-education.207584/']https://www.pricescope.com/community/threads/radiant-diamond-cut-evaluation-education.207584/[/URL]

There is a real need for better understanding about fancies in general and how to best evaluate them remotely.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

David,
Thanks for your post. I'm happy also to see others interested in this topic, and I hope the discussion stays focused and positive.

To make it clear what I personally hope to learn from this exercise, it is to hopefully determine whether it is possible for an internet shopper (who we will assume has a preference for "crushed ice" style fancy cut diamonds) to distinguish between an attractive "crushed ice" diamond and a poorly cut diamond, and if so, how they might go about doing so (without being able to view the stones in person).

I would prefer, if practicable, to limit discussion to colorless diamonds. Also, I would prefer to, at least initially, minimize references to ASET (because this tool does not, at least in the manner that ASETs are conventionally interpreted on PS, appear to yield much useful information with regards to the attractiveness of high-quality "crushed ice" style diamonds -- e.g., see Wink's quote above).

So, to start, I have several questions that I hope you can answer:

(1) If viewing a "crushed ice" type diamond that is well cut (by any definition -- meaning it sparkles in a manner that is beautiful to those who appreciate the "crushed ice" style), if you close one eye while viewing the same diamond under the same lighting conditions, does it now appear any less beautiful/sparkly/lively/dazzling? If yes, did it lose all of its scintillation, or only partially diminish in beauty, when viewed with a single eye?

(2) Do you have any photos or videos of "crushed ice" style diamonds that are poorly cut (i.e., that are not particularly attractive under reasonably "normal" viewing conditions)? If so, are there any distinguishing characteristics in these photos/videos that would set them apart from photos/videos of attractive (well-cut) "crushed ice" diamonds?

[BTW, if you think Stan Grossbard would like to weigh in on the above two questions as well, it would be an honor to hear his opinions on this -- although I think the thread would benefit from keeping the discussion general to "crushed ice" diamonds of all shapes, not just radiants.]

Finally, I would like to issue a caveat in this thread that there is a risk of misunderstanding due to the way different people use words to mean different things. For example:

The "Sharp" picture shows the actual facet pattern of the pavilion coming through the table.\
In the "Soft" picture the camera is focusing at a slightly different spot on the stone- more like what our eyes do.
All of a sudden the sharply defined facets seem to blur together. This is part of how we perceive "crushed ice"

Personally, I would have described the bottom picture ("Sharp" focus) as having the facets "blurred together", not the other way around. I think I get what David is saying, but it goes to show: (a) we have to be as careful as possible in choosing our words; and (b) pictures help a lot!

Also, I think that this set of pictures do support my contention that diamond images that many PSers call "mushy" (which tend to have large areas of blur under the table, similar to what is shown in the bottom, "sharp" picture) are the result of virtual facets that have a large path length (i.e., a large number of reflections) before light from the VF reaches the viewer. Thus, to bring these VFs into focus, one would have to focus the camera on a point located behind the stone. Presumably this is how the top, "soft focus" image was produced (David, can you confirm?).

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

Hi Drk,
Finally have a moment to ad a response...
to the questions in blue
1) Closing one eye definitely diminishes the sparkle- however it's more of overall dimmer perception.
I don't loose the "crushed ice" twinkle.

2) I have been looking for "reject" stone pics to show. I generally don't use the time to take pictures of stones I don't like.
I'm sure I can find a doggie or two this week.

One thing about a stone using VF's - since the look itself is more chaotic, there's a range of cuts, and appearances.

Maybe we can say that the "best crushed ice" stone is one with no darker areas- rather the entire appearance of the stone is tiny VF's

But there's also many well cut stones of this type that combine smaller VF's with larger VF's or a mixture of light directly off the pavilion facets and VF's.
A classic example of this type of look would be a Pear Brilliant with "crushed ice" at the tip- and top end, larger facet reflections in the middle. If it's bad we'd call it a Bow tie.
But there are well cut stones can manage to blend the look well.


Sharp focus or soft- ( aka is it a white dress with tan stripes?)
About where the camera is focusing- in the "Sharp" picture, the camera is focusing on the "skin" of the diamond- you can see the facet meet points easily. In the "soft" pic, I believe the camera is struggling to focus inside the diamond.
Something that occurred to me is the difficulty in capturing the look we're talking about here with a camera.
The "big boys" who sell the look use pictures that are ...romanticized in an attempt to capture the scintillation.
other pics ad videos make this put this type of stone at a huge and unrealistic disadvantage.
For example, if you lay this type of diamond in a GIA diamond dock it dies in the picture.

The rotating pictures present some good views, along with others that make things look worse than they may look in real life.

All this makes selecting this type of stone more of a challenge, I agree.
A good goal would be working out verbage that will help consumers identify different types of looks.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

David,
Thank you for your response.

Hi Drk,
1) Closing one eye definitely diminishes the sparkle- however it's more of overall dimmer perception.

This support your statements that stereoscopic vision is an important factor in generating the sparkle effect seen in these "crushed ice" diamonds. On the other hand:

I don't loose the "crushed ice" twinkle.

This suggests that at least some of the beauty ("twinkle") of these stones is not dependent on stereoscopic vision. This is important because it implies it is theoretically possible to identify well-cut "crushed ice" diamonds using conventional (non-stereo) photography and videography.

Follow-Up Question: Examining stones in person, with what success rate do you think you would be able to discern between a well-cut and a badly cut "crushed ice" diamond, if observing both with one eye closed?

2) I have been looking for "reject" stone pics to show. I generally don't use the time to take pictures of stones I don't like.
I'm sure I can find a doggie or two this week.

OK, that would be great as a point of comparison. Even if you don't have many pictures to show, perhaps you can speak from experience (with regards to how you may be able to tell apart, from photos alone, whether you're looking at a "good" or a "bad" crushed ice diamond).

since the look itself is more chaotic, there's a range of cuts, and appearances.

That's understandable. For purposes of this discussion, maybe we can focus on what you're calling "best crushed ice"... i.e., the type of crushed ice that is most likely to be universally appreciated by the largest number of people.

A classic example of this type of look would be a Pear Brilliant with "crushed ice" at the tip- and top end, larger facet reflections in the middle. If it's bad we'd call it a Bow tie.But there are well cut stones can manage to blend the look well.

Understood. Probably the presence or absence of adequate "blending" is beyond the scope of the discussion in this thread. However, it still would be useful to know whether, when one sees evidence of "crushed ice" type areas in the points of a pear, marquise, or oval (which may also have a crisp/large facet region in the belly), it is possible to tell whether these "crushed ice" areas are sparkly or not. I think this is a similar question to our main question of what to look for when trying to identify well cut "crushed ice" diamonds by looking only at photos and videos.

About where the camera is focusing- in the "Sharp" picture, the camera is focusing on the "skin" of the diamond- you can see the facet meet points easily. In the "soft" pic, I believe the camera is struggling to focus inside the diamond.

Were these photos captured using automatic focus and trial-and-error? Or was the lens manually focused?

other pics ad videos make this put this type of stone at a huge and unrealistic disadvantage.
For example, if you lay this type of diamond in a GIA diamond dock it dies in the picture.

I agree, this is part of what I'm trying to figure out in this thread.

I think a good starting point, based on the premise that you (and possible other experts, like Mr. Grossbard) are able to tell apart good vs. bad (or at least "promising" vs. "hopeless") crushed-ice style diamonds using only pictures and video of the stones, is for us to try to figure out how you accomplish that feat. As you can tell, I'm using a Socratic approach and asking you a million questions to try to develop some insight into your thought process. I think it's difficult to be completely self-aware of all nuances of one's own thought processes, so therefore I think the Socratic Q&A approach will be more effective than to have you attempt to lay it all out for us in one fell swoop.

Assuming we make some headway on this front, it is possible that we might ultimately generate some ideas for how to better present this type of diamond to consumers who are interested in them.

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

This is a very thought provoking discussion, I can't thank you enough for your perceptive questions drk.
One eye closed
When learning to loupe stones, many people's inclination is to close the other eye ( the one not looking in the loupe.)
This is a great way to damage one's eyes- if you're looking in a loupe a lot.
That's one reason the one eyed approach is not a good approach IMO
In general, when examining a diamond, I yearn to see it as closely as possible.
Closing one eye distorts the vision, and you just can't see as well.

Plus, the bottom line for me, when it comes to diamond evaluation, including cut, is how does the stone look?
No matter how many times I look in the loupe, I'm never sold till I'm looking at it from arm's length.
Again, one eye wont allow the best view of the stone


I hate to "knock down" a well meaning idea- but for me, it does not work.
Maybe others will have different opinions.

About the "best crushed ice"- and this is truly central to the topic of the thread:
I do not feel we can say which is "best"
The reason is that there's so many different flavors.
For example- rectangular stones have different considerations.In most cases, stones that are a bit longer will have a mix of small VF and larger reflections- like this



The above stone is a kewl example as it's certainly not "best make"- but it still had a lot going for it ( and it was an I1, therefore lower priced)

If we limit the discussion to only stones with total crushed ice look we've left out some important types of stones.

Camera- auto focus.
I take a ton of pics, letting the camera decide on all settings- and then I pick the most representative ones.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

Again, one eye wont allow the best view of the stone

I hate to "knock down" a well meaning idea- but for me, it does not work.

David, sorry, I didn't mean to actually recommend using only one eye in practice, and I hope I didn't give you a headache! The question was simply meant as a one-off experiment: If, in an experiment, you are able to tell apart a good "crushed ice" diamond from a bad "crushed ice" diamond using only one eye, then this proves that in principle, there should be a way to help internet shoppers pick out the nice "crushed ice" diamonds using only such images that are commonly available (i.e., photos and videos that are not stereoscopic).

So if the answer to the question is yes, then I would be interested in exploring how one might make such photo-based evaluations in practice, either using the types of photos currently found online, or by making some alternative suggestions for how to take photographs or videos that are more helpful to the consumer. It would be an interesting challenge to me to take on this problem.

On the other hand, if the answer is no -- i.e., if you do require both eyes in order to tell a good "crushed ice" diamond from a badly cut one (is this what you imply when you say "for me, it does not work"?), then it may be very challenging to help internet shoppers select the nice "crushed ice" diamonds from among available online offerings until such time as stereoscopic video becomes widely available on diamond shopping websites.

If we limit the discussion to only stones with total crushed ice look we've left out some important types of stones.

That's fine, we don't have to limit the discussion.

Thanks for the added picture; I will maybe post some questions about it after I get your take on the above.

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

For me, a worthy goal is showing folks how to get an idea of the different "Flavors" commonly seen.
If someone want's a rectangular diamond, and many people do, we can
a) go to "PS speak" and discuss how the light performance will suffer in virtually any rectangular diamond, as compared to a round. You're going to have leakage. Gasp!!

b) look at how different cutters respond to the different considerations posed and the resultant optical signatures. The way leakage can be used as part of a successful "crushed ice" recipe.
Leakage.
There, I said it again.
It's not, by definition, a "bad" characteristic on in a Fancy Shaped diamond.


One of the coolest aspects of Fancy Shaped Diamonds is the endless variations possible in make and model. This makes life far more interesting, and classifications far more difficult.
Still very worthwhile

If the discussion took a new direction, I do think we can use the available pics and videos to assist people regardless of the stereoscopic issue.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

If the discussion took a new direction, I do think we can use the available pics and videos to assist people regardless of the stereoscopic issue.

Not sure exactly what direction you wish to go in, but by all means, go for it -- I'll see if I learn something as a result...

I'll again try to restate some of the specifics of what I'm personally trying to understand, in case it moves you respond:

Take for instance, the diamond you posted above. I would say that with regards to focal plane and depth-of-focus, it is fairly representative of how an online diamond photograph may be presented on a vendor website: the table, girdle, as well as most of the physical facet edges in the crown and pavilion are in focus. In such photographs, we sometimes see areas that are blurry (e.g., the areas that are circled in red below). On PS, such regions are often labeled "mush"... maybe this is an unfortunate choice of a word due to possible negative connotations, but nonetheless, I will use the term here without prejudice (i.e., recognizing that there may not, in fact, be any inherent negative qualities associated with such "mushy" zones). Your first set of photographs (of the FY diamond) reveal that by refocusing the camera to mimic the adaptable focus of the human eye, a large number of small VFs come into focus in such "mushy" areas.



Now that I've defined my terminology (specifically, what I mean and what I don't mean when I use the word "mush"), here is my actual question:

Are all areas that appear "mushy" in pictures that have been focused the conventional way (as in the photo above) always regions that are sources of some form of sparkle? Or do there exist (in poorly cut diamonds) some regions, which manifest as "mush" in photos, but that do not contribute positively to the scintillation of the stone -- i.e., do you ever find "mush" that does not produce a "bottomless bucket of dazzling ice" effect?

In other words, is all "mush" the same, or is there "good mush" and "bad mush"?

In a diamond such as the one above, which also has areas of crisp/non-mushy faceting (non-circled areas above, in which the VFs are in a focal plane very close to the focal plane of the physical facets), would you say that the beauty of the diamond is there in spite of the "mush", or because of the mush? Or does the answer go either way, depending on the diamond?

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

Great questions DRK!

When I said the "discussion taking a new direction" I meant the overall tone of crushed ice discussions on PS.
This particular thread is totally "different"- and in a very good way.


I believe we already returned the pictured cushion stone to the vendor.
I will check tomorrow.
If it's here I'll use to answer, if not I'll pick another stone that has a degree of mush.

I love your questions and want to have diamonds n front of me ( and fresher eyes) to answer

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

I love your questions and want to have diamonds n front of me ( and fresher eyes) to answer

Sounds great. I hope you'll indulge me and also try the one-eye experiment (or you may want to hold off on that one until you come across a less beautiful "crushed ice" diamond that you can compare to a finer specimen, using one-eyed observation).

 

[Texas Leaguer]

Re: Friendly discussion about bottomless buckets of dazzling

If the discussion took a new direction, I do think we can use the available pics and videos to assist people regardless of the stereoscopic issue.

Not sure exactly what direction you wish to go in, but by all means, go for it -- I'll see if I learn something as a result...

I'll again try to restate some of the specifics of what I'm personally trying to understand, in case it moves you respond:

Take for instance, the diamond you posted above. I would say that with regards to focal plane and depth-of-focus, it is fairly representative of how an online diamond photograph may be presented on a vendor website: the table, girdle, as well as most of the physical facet edges in the crown and pavilion are in focus. In such photographs, we sometimes see areas that are blurry (e.g., the areas that are circled in red below). On PS, such regions are often labeled "mush"... maybe this is an unfortunate choice of a word due to possible negative connotations, but nonetheless, I will use the term here without prejudice (i.e., recognizing that there may not, in fact, be any inherent negative qualities associated with such "mushy" zones). Your first set of photographs (of the FY diamond) reveal that by refocusing the camera to mimic the adaptable focus of the human eye, a large number of small VFs come into focus in such "mushy" areas.



Now that I've defined my terminology (specifically, what I mean and what I don't mean when I use the word "mush"), here is my actual question:

Are all areas that appear "mushy" in pictures that have been focused the conventional way (as in the photo above) always regions that are sources of some form of sparkle? Or do there exist (in poorly cut diamonds) some regions, which manifest as "mush" in photos, but that do not contribute positively to the scintillation of the stone -- i.e., do you ever find "mush" that does not produce a "bottomless bucket of dazzling ice" effect?

In other words, is all "mush" the same, or is there "good mush" and "bad mush"?

In a diamond such as the one above, which also has areas of crisp/non-mushy faceting (non-circled areas above, in which the VFs are in a focal plane very close to the focal plane of the physical facets), would you say that the beauty of the diamond is there in spite of the "mush", or because of the mush? Or does the answer go either way, depending on the diamond?

Drk,
My compliments on the patient and methodical way you are approaching this subject. Where were you the last time this discussion was attempted!

One comment on your last question. I am not sure I understand your statement about the effect of the focal plane in the photo above. It looks like the table facet junctions are in pretty good focus as are the pavilion facets down in the center. That indicates to me that depth of field is wide enough to capture crisp VFs where they exist in the stone. If that is correct, the areas that look mushy are probably the result of the blurring of the facet structure due to chaotic/overlapping output of the VF's in those areas (aka mush).

I am not an expert in fancy cut diamonds which is one reason I have tried to follow these discussion in the past. However, I have in my career bought and sold and looked at a great many fancies. And I can say with confidence that there is "bad mush" out there! As for the existence of "good mush", I will keep an open mind.

I will also say for the record that I think a well cut crushed ice look can be very beautiful.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

Bryan,
Thanks for the compliment. Glad you're following the thread.. I may have some questions for you, too, later.

One comment on your last question. I am not sure I understand your statement about the effect of the focal plane in the photo above. It looks like the table facet junctions are in pretty good focus as are the pavilion facets down in the center.

So far, I agree. Let's say, for the sake of argument, that the depth-of-focus and the diamond are both 10mm deep, and that the focal point is in the center of the stone. Thus, the table and culet (and all real facet junctiosn in between) should all be in focus -- which they pretty much are in the photo, as you have noted.

That indicates to me that depth of field is wide enough to capture crisp VFs where they exist in the stone.

I don't think this statement necessarily follows from the above. When we see VF edges in a stone, what we see is actually light that has come from one of the physical facet edges, and subsequently been internally reflected inside the diamond at least once, before ultimately escaping through the table or crown and reaching the camera. Now, if we go with the above assumptions (i.e., finite depth-of-focus similar to the depth of of the diamond, and a camera focal plane that passes through the stone), then what happens if the light ray that produces a VF has to bounce (reflect) many times before reaching the camera? The result would be that the total pathlength of the light ray can become so long that the VF edge (i.e., the image of the physical facet edge at the start of the light ray) is now out of focus. If we unravel the contorted light path and make it a straight line, the location of the VF would appear to be located somewhere behind the diamond, outside the focal plane.

In David's first set of images (of the FY diamond), we can see that when the camera has chosen to focus on a point behind the diamond (the image he labeled "Soft Focus"), a large number of VFs (which were previously blurry, when the camera was focused inside the diamond) now come into focus.

Now, I don't disagree that it is possible in some cases for VF edges to appear blurry even if one has chosen an appropriate focal point to match the total path length of the light ray. Specifically, if the diamond has poor polish, then each reflection will degrade the image of the VF until it ultimately could appear quite indistinct by the time the light ray reaches the camera (or eye). But I don't think this is the case with every diamond that gets labeled "mushy".

Of course, there are other factors that contribute both to the "mush" effect and to the actual appearance (good or bad) of the diamond as viewed by a human, but I don't want to get ahead of myself in the discussion...

So hopefully the above convinces you that it is possible to have "crisp" VFs that appear as "mush" in conventional photos, due to limited (and fixed) depth-of-focus in conevtnional photography. The human eye, of course, would be able to adjust its focus to see these long-pathlength VFs clearly, and I believe that this in part explains the effect of looking into a "bottomless bucket" or a "portal" -- this may happen when the eye fouses on VFs that have path lengths much longer than the dimensions of the diamond, thus creating an illusion of looking through the diamond into a virtual universe of sparkle.

 

[Texas Leaguer]

Re: Friendly discussion about bottomless buckets of dazzling

Bryan,
Thanks for the compliment. Glad you're following the thread.. I may have some questions for you, too, later.

One comment on your last question. I am not sure I understand your statement about the effect of the focal plane in the photo above. It looks like the table facet junctions are in pretty good focus as are the pavilion facets down in the center.

So far, I agree. Let's say, for the sake of argument, that the depth-of-focus and the diamond are both 10mm deep, and that the focal point is in the center of the stone. Thus, the table and culet (and all real facet junctiosn in between) should all be in focus -- which they pretty much are in the photo, as you have noted.

That indicates to me that depth of field is wide enough to capture crisp VFs where they exist in the stone.

I don't think this statement necessarily follows from the above. When we see VF edges in a stone, what we see is actually light that has come from one of the physical facet edges, and subsequently been internally reflected inside the diamond at least once, before ultimately escaping through the table or crown and reaching the camera. Now, if we go with the above assumptions (i.e., finite depth-of-focus similar to the depth of of the diamond, and a camera focal plane that passes through the stone), then what happens if the light ray that produces a VF has to bounce (reflect) many times before reaching the camera? The result would be that the total pathlength of the light ray can become so long that the VF edge (i.e., the image of the physical facet edge at the start of the light ray) is now out of focus. If we unravel the contorted light path and make it a straight line, the location of the VF would appear to be located somewhere behind the diamond, outside the focal plane.

In David's first set of images (of the FY diamond), we can see that when the camera has chosen to focus on a point behind the diamond (the image he labeled "Soft Focus"), a large number of VFs (which were previously blurry, when the camera was focused inside the diamond) now come into focus.

Now, I don't disagree that it is possible in some cases for VF edges to appear blurry even if one has chosen an appropriate focal point to match the total path length of the light ray. Specifically, if the diamond has poor polish, then each reflection will degrade the image of the VF until it ultimately could appear quite indistinct by the time the light ray reaches the camera (or eye). But I don't think this is the case with every diamond that gets labeled "mushy".

Of course, there are other factors that contribute both to the "mush" effect and to the actual appearance (good or bad) of the diamond as viewed by a human, but I don't want to get ahead of myself in the discussion...

So hopefully the above convinces you that it is possible to have "crisp" VFs that appear as "mush" in conventional photos, due to limited (and fixed) depth-of-focus in conevtnional photography. The human eye, of course, would be able to adjust its focus to see these long-pathlength VFs clearly, and I believe that this in part explains the effect of looking into a "bottomless bucket" or a "portal" -- this may happen when the eye fouses on VFs that have path lengths much longer than the dimensions of the diamond, thus creating an illusion of looking through the diamond into a virtual universe of sparkle.

Intuitively I can understand how VFs deriving from multiple bounces could degrade in terms of any actual facet edges they are reflecting leading to a blurrier effect. And the facet design or execution of the design could concentrate them in localized areas of the stone. I am much less clear on how the actual length of the ray path would determine what we see in this particular respect. It just seems to me that what the camera catches, provided the depth of field is wide enough, is essentially what the eye would see in the specific lighting environment in which the diamond was photographed.(setting aside the issue of stereovision).

With regard to the fancy colored diamond images and the "soft" and "sharp" focus, this effect is soley a result of the depth of field and/or focal point combinations not bringing the entirety of the diamond into focus in either photo. So, a poorly taken photo could certainly give a false impression of some mush where areas of the diamond are out of focus. But in a high quality photo would tend to reveal mush. In the fancy color example, because there are two shots bringing into focus the top and bottom of the diamond, and since both show minimal mush in the areas that are in focus, I would say the fancy color is probably an example of a well cut crushed ice. The white example that you marked up is most likely an example of a stone with some detrimental mush.

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

I am much less clear on how the actual length of the ray path would determine what we see in this particular respect. It just seems to me that what the camera catches, provided the depth of field is wide enough, is essentially what the eye would see

OK, apparently I have a little more convincing to do...

Above, I have bolded the assumption that may be leading you astray. But let's start with a thought experiment.

Imagine you are in a funhouse hall-of-mirrors, standing between two parallel mirrors that face each other, 1 m apart. What will you see? You will see a virtual version of yourself (i.e. a reflected image) that appears to stand 1 meter away from you, looking back at you. You will also see the back of a second Virtual Bryan (VB) apparently standing 2 m away. And then a third VB, standing 3 m away, facing you. And so on. Now, suppose you have a camera configured with a large aperture (low F-stop), which gives you a limited depth-of-field -- for sake of argument, let's say the depth-of-field is around 0.5 m and therefore capable of bringing one VB into sharp focus. If you now try to take a photo of the first VB (the one standing 1 m away), then the second VB, which has a longer pathlength to the camera (2 m), will be sufficiently far away from the focal plane of the camera that he will be blurry in the photograph. The 3rd, 4th, and higher generation VBs will be completely "mushy" in the photo. Meanwhile, your eyes have the ability to dynamically focus on the different VBs, and your brain does some fancy image processing to make it appear that a large number of them are simultaneously in focus. You get the illusion of staring into infinity.

So, the limited depth-of-field is significant. One cannot assume that "the depth of field is wide enough." In macro photography, one can typically only achieve a depth-of-field of around 0-10mm, so while it is possible to bring the physical facets of a reasonably-sized diamond into focus, it would typically not be possible to then simultaneously have all of the virtual facets in focus -- probably only those that have been reflected only once, maybe twice. As a corollary, if one changes the camera focal plane to a point behind the diamond, then the photo will show a subset of the VFs that your eyes are able to focus on.

I hope we are now on the same page with regards to the focal plane business!

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

Readers: I suppose it was only a matter of time, but a post was just made (on 22 Apr 2015 at 19:19 by a user with only 1 post, who created his account about an hour prior), which completely misses the point and spirit of this thread. I have reported the post and hope it will be deleted by the mods soon, but in case you can still see it, I sincerely hope you will do as I am doing and simply ignore it (and any further posts by this user). I'm trying something different in this thread, and as I explained in the original post, this is not the place to be adversarial.

I sincerely hope for no further attacks (or counter-attacks). Let's get on with our friendly discussion!

 

[drk14]

Re: Friendly discussion about bottomless buckets of dazzling

Readers: I suppose it was only a matter of time, but a post was just made (on 22 Apr 2015 at 19:19 by a user with only 1 post, who created his account about an hour prior), which completely misses the point and spirit of this thread. I have reported the post and hope it will be deleted by the mods soon, but in case you can still see it, I sincerely hope you will do as I am doing and simply ignore it (and any further posts by this user). I'm trying something different in this thread, and as I explained in the original post, this is not the place to be adversarial.

I sincerely hope for no further attacks (or counter-attacks). Let's get on with our friendly discussion!

Readers of this thread,
I would just like to re-iterate that if you have found this thread useful or interesting so far, please do not respond to any posts by the user referenced above (if his posts are still visible). This will only derail the thread, and make it harder for the mods to clean up.

Thanks!

 

[pfunk]

Re: Friendly discussion about bottomless buckets of dazzling

Readers: I suppose it was only a matter of time, but a post was just made (on 22 Apr 2015 at 19:19 by a user with only 1 post, who created his account about an hour prior), which completely misses the point and spirit of this thread. I have reported the post and hope it will be deleted by the mods soon, but in case you can still see it, I sincerely hope you will do as I am doing and simply ignore it (and any further posts by this user). I'm trying something different in this thread, and as I explained in the original post, this is not the place to be adversarial.

I sincerely hope for no further attacks (or counter-attacks). Let's get on with our friendly discussion!

Readers of this thread,
I would just like to re-iterate that if you have found this thread useful or interesting so far, please do not respond to any posts by the user referenced above (if his posts are still visible). This will only derail the thread, and make it harder for the mods to clean up.

Thanks!

Thanks False Moderator. Good luck running Pricescope and promoting Diamonds By Lauren in the name of "Education".

NonLuddite,

I think your opinions and comments should be welcomed just as anyone else's, but I do think it seems odd how many old threads you are able to dig up after just joining and how you seem to know the names of all the contributing trade members. I hope you can enlighten us and then participate in the discussion in a civil manner as the OP intended.

 

[hiratop]

Re: Friendly discussion about bottomless buckets of dazzling

So hopefully the above convinces you that it is possible to have "crisp" VFs that appear as "mush" in conventional photos, due to limited (and fixed) depth-of-focus in conevtnional photography. The human eye, of course, would be able to adjust its focus to see these long-pathlength VFs clearly, and I believe that this in part explains the effect of looking into a "bottomless bucket" or a "portal" -- this may happen when the eye fouses on VFs that have path lengths much longer than the dimensions of the diamond, thus creating an illusion of looking through the diamond into a virtual universe of sparkle.

That kind of diamond I find the most alluring and mysterious there is. There are many issues I would love to hear more about:

- What kind of relationship is there between perfect optical symmetry and the "perfect" crushed ice effect. Will perfect optical symmetry enhance the effect or detract from it? Is there even one crushed ice stone in the world with perfect optical symmetry?

- For fancy colours the crushed ice effect is a byproduct of trying to lengthen the internal paths of light leaving towards the eye, thereby amplifying the saturation of face up colour. Is there any (published) research how to cut a radiant or some other shape to maximize the internal light path length and what would such optimal radiants look like? Crushed ice? How would they perform concerning attributes optimised for rounds (brightness, scintillation, dispersion)?

- Current cutting technologies are far too imprecise to position second and later generations virtual facets precisely, right? If they were not, could we cut "crushed ice" (and other) stones that would look visibly better "in some ways" than stones doable now?

 

[Rockdiamond]

Re: Friendly discussion about bottomless buckets of dazzling

I am much less clear on how the actual length of the ray path would determine what we see in this particular respect. It just seems to me that what the camera catches, provided the depth of field is wide enough, is essentially what the eye would see

OK, apparently I have a little more convincing to do...

Above, I have bolded the assumption that may be leading you astray. But let's start with a thought experiment.

Imagine you are in a funhouse hall-of-mirrors, standing between two parallel mirrors that face each other, 1 m apart. What will you see? You will see a virtual version of yourself (i.e. a reflected image) that appears to stand 1 meter away from you, looking back at you. You will also see the back of a second Virtual Bryan (VB) apparently standing 2 m away. And then a third VB, standing 3 m away, facing you. And so on. Now, suppose you have a camera configured with a large aperture (low F-stop), which gives you a limited depth-of-field -- for sake of argument, let's say the depth-of-field is around 0.5 m and therefore capable of bringing one VB into sharp focus. If you now try to take a photo of the first VB (the one standing 1 m away), then the second VB, which has a longer pathlength to the camera (2 m), will be sufficiently far away from the focal plane of the camera that he will be blurry in the photograph. The 3rd, 4th, and higher generation VBs will be completely "mushy" in the photo. Meanwhile, your eyes have the ability to dynamically focus on the different VBs, and your brain does some fancy image processing to make it appear that a large number of them are simultaneously in focus. You get the illusion of staring into infinity.

So, the limited depth-of-field is significant. One cannot assume that "the depth of field is wide enough." In macro photography, one can typically only achieve a depth-of-field of around 0-10mm, so while it is possible to bring the physical facets of a reasonably-sized diamond into focus, it would typically not be possible to then simultaneously have all of the virtual facets in focus -- probably only those that have been reflected only once, maybe twice. As a corollary, if one changes the camera focal plane to a point behind the diamond, then the photo will show a subset of the VFs that your eyes are able to focus on.

I hope we are now on the same page with regards to the focal plane business!

BINGO- Amazingly I was thinking of the exact same analogy.
As the reflection bounces again and again, it does loose focus.
I do believe DRK hit this one on the head- there's simply no way for a camera to focus on both original as virtual reflections and have them be in focus- just as the eye can not.
Remember the physical size of the diamond. By increasing the size of the lens ( low Fstop) we compress the depth of field- but the actual distances are so small that infinitesimal differences result in dramatic shifts in focus.
When usng the ViBox, there's a step where the operator needs to manually focus the lens ( using the computer) on the diamond. In this way, it's incredibly apparent where on the diamond you are focusing.
It's a super fine calibration, yet I always find myself wanting to get between the two potential camera solutions.
Without a doubt, this all relates to how our eyes struggle to focus on the "crushed ice"- but I'm really not sure exactly how.

I'd like to point out that this is a learning experience for me as well.
I have always looked at diamonds physically, and have been able to determine how well the stone is made because the diamond is in front of me.
So the translation of "crushed ice" to "PS speak" is not truly formulated in my head. In other words, I don't (yet) know the answers.


I see it was an interesting night last night.
Part of the "PS speak" which we will need to tackle does involve the terminology- and methodology of picking a diamond.

There was a thread yesterday where someone asked their first question here on PS- about oval diamonds.
They were immediately informed that ovals don't have such great light performance.
For me, this is integral to the issue.
The entire definition of "Light Performance" is skewed in such a manner to favor a certain type of stone.
If I want an oval, what difference does it make that a round can be shown to have more of something or other based on ASET?

When light bounces around inside the diamond, it just makes sense that the ray of light will loose a slight bit of brightness.
In well cut stones using VF's as part of the beauty recipe, we get something back in return.
Sometimes it's spread, sometimes it's a lack of contrast that seems to spread the sparkle out across the entire diamond ( AKA as even crushed ice)
Hopefully this discussion can help put some of these aspects in better perspective.

 

[Texas Leaguer]

Re: Friendly discussion about bottomless buckets of dazzling

I am much less clear on how the actual length of the ray path would determine what we see in this particular respect. It just seems to me that what the camera catches, provided the depth of field is wide enough, is essentially what the eye would see

OK, apparently I have a little more convincing to do...

Above, I have bolded the assumption that may be leading you astray. But let's start with a thought experiment.

Imagine you are in a funhouse hall-of-mirrors, standing between two parallel mirrors that face each other, 1 m apart. What will you see? You will see a virtual version of yourself (i.e. a reflected image) that appears to stand 1 meter away from you, looking back at you. You will also see the back of a second Virtual Bryan (VB) apparently standing 2 m away. And then a third VB, standing 3 m away, facing you. And so on. Now, suppose you have a camera configured with a large aperture (low F-stop), which gives you a limited depth-of-field -- for sake of argument, let's say the depth-of-field is around 0.5 m and therefore capable of bringing one VB into sharp focus. If you now try to take a photo of the first VB (the one standing 1 m away), then the second VB, which has a longer pathlength to the camera (2 m), will be sufficiently far away from the focal plane of the camera that he will be blurry in the photograph. The 3rd, 4th, and higher generation VBs will be completely "mushy" in the photo. Meanwhile, your eyes have the ability to dynamically focus on the different VBs, and your brain does some fancy image processing to make it appear that a large number of them are simultaneously in focus. You get the illusion of staring into infinity.

So, the limited depth-of-field is significant. One cannot assume that "the depth of field is wide enough." In macro photography, one can typically only achieve a depth-of-field of around 0-10mm, so while it is possible to bring the physical facets of a reasonably-sized diamond into focus, it would typically not be possible to then simultaneously have all of the virtual facets in focus -- probably only those that have been reflected only once, maybe twice. As a corollary, if one changes the camera focal plane to a point behind the diamond, then the photo will show a subset of the VFs that your eyes are able to focus on.

I hope we are now on the same page with regards to the focal plane business!

Thank you for that explanation. I did not appreciate that concept, and it still does not seem intuitive to me, but I can see where it would be relevant.