Painted girdles

[sleeprequired]

http://www.goodoldgold.com/4Cs/NewCutGrading/Painting/

According to this article, most diamonds online have painted girdles, is this correct and is it a problem?

I'm referring to the ASET for a painted girdle in the article. Nearly every ASET I see has the green ^ things in between the arrow heads on the stars (hope I'm getting that right).

WF have it. BGD have it. GOG have it.

http://www.goodoldgold.com/diamond/8892/
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2517161.htm
http://www.briangavindiamonds.com/Diamonds/diamond-details/1.308-F-VS1-round-Diamond-AGS-104054185003#!prettyPhoto[gallery2]/0/

So is the article correct?, am I reading it correct?, or am I totally off the mark?

 

[TitanCi]

I see what you're saying, but I imagine the labs would report it on the reports... no??? IIRC, GIA is very strict on that... I'm curious to know what the experts say too

 

[0-0-0]

This article goes into more detail: https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds

I guess you can argue that most stones have some degree of painting, but it's not really an issue until it's severe enough. Both AGS/GIA don't downgrade cut until average crown painting gets above 6-7 degrees according to the article.

In terms of the ASET images, I don't see any obvious painting on the WF stone. The BGD stone looks like it has a few dug out spots on the girdle, but nothing serious. On the other hand, I think it's pretty clear the GOG stone has a painted girdle, possibly done to hit 1.5 ct.

 

[Rhino]

Just to clarify. Yes ... many diamonds do in fact have some degree of painting or digging. If you were to analyze Helium reports (which show the exact degree to which diamonds are painted or dug) on every round (including many finely cut H&A's) you will note a certain small percentage of painting or digging on many of them. The underlying question is, to what degree is it painted or dug? In most ideal cuts its not enough to make a hoot over. GIA and AGS have different tolerances for what constitutes their top grade but that is something you'll see reported on the information we'll publish.

Kind regards,
Rhino

 

[TitanCi]

Just to clarify. Yes ... many diamonds do in fact have some degree of painting or digging. If you were to analyze Helium reports (which show the exact degree to which diamonds are painted or dug) on every round (including many finely cut H&A's) you will note a certain small percentage of painting or digging on many of them. The underlying question is, to what degree is it painted or dug? In most ideal cuts its not enough to make a hoot over. GIA and AGS have different tolerances for what constitutes their top grade but that is something you'll see reported on the information we'll publish.

Kind regards,
Rhino

Mr. Jonathon! So is it true what the poster says of your stone? Just joking!

I think I can see a little of it now when I compare it to the stones in reference in the article. Perhaps only 2-3 deg ACP???

 

[sleeprequired]

Just to clarify. Yes ... many diamonds do in fact have some degree of painting or digging. If you were to analyze Helium reports (which show the exact degree to which diamonds are painted or dug) on every round (including many finely cut H&A's) you will note a certain small percentage of painting or digging on many of them. The underlying question is, to what degree is it painted or dug? In most ideal cuts its not enough to make a hoot over. GIA and AGS have different tolerances for what constitutes their top grade but that is something you'll see reported on the information we'll publish.

Kind regards,
Rhino

thanks for responding, and i'd like to point out that I posted three links to the major online people in the interest of fairness. I have found GOG to be a fabulous source of information in terms of documents, videos, and everyone online here from GOG responding with balance, fairness and above all objectivity.

**edit** i just wanted to be clear that I'm not having a go at any vendor and that I appreciate your response. Not sure the sentence above reads that way Rhino. Your videos online have been enlightening. Very useful for a buyer who cannot see the merchandise.

 

[Rhino]

Thanks for the kind words sleep. I didn't take it in the wrong spirit whatsoever. I understand you're learning and your question is very valid. I happen to have a video that demonstrates the visual differences one will see between a classic girdle, a girdle painted akin to the one you posted a link to and also a Solasfera as it has a solid edge to edge red reflector image (yet without painting).

Titan ... you card. Actually if you look at the Helium Report on that diamond in the lower right box you'll see that particular diamond is painted -6.46 degrees (avg) and if you look at the GIA Facetware tab on that same page you'll see it got dinged from the Ex grade to the VG grade and that is precisely why too.

Having said all that, the diamond does happen to be an extremely precision cut stone and does happen to be what I consider the darn best looking type of GIA VG out there and why I'm willing to back it with our lifetime policies.

All the best,
Rhino

 

[John P]

This article goes into more detail: http://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds

I guess you can argue that most stones have some degree of painting, but it's not really an issue until it's severe enough. Both AGS/GIA don't downgrade cut until average crown painting gets above 6-7 degrees according to the article.

In terms of the ASET images, I don't see any obvious painting on the WF stone. The BGD stone looks like it has a few dug out spots on the girdle, but nothing serious. On the other hand, I think it's pretty clear the GOG stone has a painted girdle, possibly done to hit 1.5 ct.

I composed that article soon after GIA introduced their RB cut grade. We worked closely with about a dozen diamonds at differing increments of crown painting to select the six we featured and submitted to GIA and AGSL. I remember them well and still have my notes and data. In a clinical analysis I'd put this photo forward as most-useful.



As it relates to normal viewing, my own experience has been that strong observers with an understanding of what to look for will detect visible differences (CP only) at about 1 click on the tang. To be safe I call it >=3.5 degrees ACP for those with eagle eyes. So a normally indexed diamond compared to one with 1.5 deg ACP will has negligible visual differences in human terms. Same with 4.0 deg ACP next to 5.5 deg ACP... But place a normally indexed stone next to one with 4.0 deg ACP and a normally keen observer - or experienced pro - can tease out the different characteristics in optical performance.

Of course this is much like discussing what is eye-clean. YMMV. And logically, seasoned vets may detect more than the average (even keen-eyed) person who does not view dozens of different diamonds daily. Or not. It's quite personal; like color perception or clarity perception.

 

[TitanCi]

This forum is awesome. I want to go to GIA so I can learn and take that gemology course. There's so much knowledge that the pros here have. I wanna quit my day job to deal with diamonds all day now! Mr Pollard or Mr Jonathan... looking for an intern???

 

[sleeprequired]

Thanks for those images. Ok so from other images I had seen I thought there were 2 key indicators.

Firstly the green ^ in between the middle of the arrow heads, but even your 0.5 example has that so I think that's incorrect.

Secondly, and your images seem to confirm, I thought it came down to the two little lines coming from the girdle in between the tips of the arrow heads.

So it's quite possible to have those green ^'s in between the arrow heads and not have painting.

Seems the key indicator is those lines coming from the girdle. Black no painting, green a little painting, and then the bigger they get the more painting.

If anyone would like to correct my terminology as well I would appreciate it.

 

[0-0-0]

Thanks for your articles and observations, Rhino and John! They are all very insightful!

sleeprequired, I think you got it. There's actually a video from GOG comparing the stone with painting discussed here against a stone with negligible amounts of painting: [URL='https://www.pricescope.com/community/threads/few-questions-for-a-newbie-about-cut-and-optics.172972/#p3150005']https://www.pricescope.com/community/threads/few-questions-for-a-newbie-about-cut-and-optics.172972/#p3150005[/URL]

 

[John P]

Thanks for those images. Ok so from other images I had seen I thought there were 2 key indicators.

Firstly the green ^ in between the middle of the arrow heads, but even your 0.5 example has that so I think that's incorrect... (snip) ...So it's quite possible to have those green ^'s in between the arrow heads and not have painting.

Definitely. What you're seeing are facet edges; where the stars meet the crown mains. I call them Star-Vs and they have nothing to do with painting or digging of the break facets. In fact they share only a single meet-point with the upper breaks. The star Vs are present in all RBCs but shows up better in more robust ASET and IS setups, especially those with backlighting where points of contrast leakage (windowing) in normally indexed stones better-illuminate the edges.

You can see what I mean here: https://www.pricescope.com/files/images/journal/Visible_Effects/image011.jpg

In the same way as contrast leakage points contribute in a positive way, I classify the Star-V edges as a positive contrast component, albeit a slight one.

Secondly, and your images seem to confirm, I thought it came down to the two little lines coming from the girdle in between the tips of the arrow heads. Seems the key indicator is those lines coming from the girdle. Black no painting, green a little painting, and then the bigger they get the more painting. If anyone would like to correct my terminology as well I would appreciate it.

That's a good general explanation. When the diamond is brillianteered in a manner that takes it away from normal indexing those break facets begin to draw their light from less optimal areas. It also eliminates the contrast leakage points discussed above.

We really must take it with a grain of salt, as I explained in a prior post, since the differences we see between these six candidates in ASET - and IS - are far easier to detect than any normal real-life differences.

 

[Karl_K]

I once made the statement that every RB ever cut and likely ever will be cut has some painting and digging present. No one has been able to prove me wrong.
It is just the nature of cutting a super hard material with varying hardness and grain along with how diamonds are cut on a wheel.

What get lost at times in the discussion is that different crown angles can tolerate less or more painting/digging.
For example a 35 degree crown can tolerate much more painting before showing visible ill effects than the same painting on a 33 degree crown.
The GIA approach a certain number for all crowns is a bad over simplification.

Because most of the effects show up in scintillation it is hard to put into words and to say just where the bad point is for any given set of angles.
However I think more people than given credit for will pick up the effects when shown side by side a diamond with minimal painting/digging and one with a lot in the right lighting.

 

[John P]

I once made the statement that every RB ever cut and likely ever will be cut has some painting and digging present. No one has been able to prove me wrong. It is just the nature of cutting a super hard material with varying hardness and grain along with how diamonds are cut on a wheel.

100% correct. And who has tried to prove you wrong? ...I can only imagine it was a theorist, not anyone who has ever cut a diamond

What get lost at times in the discussion is that different crown angles can tolerate less or more painting/digging.
For example a 35 degree crown can tolerate much more painting before showing visible ill effects than the same painting on a 33 degree crown. The GIA approach a certain number for all crowns is a bad over simplification.

Again, a great observation. The article I composed above is applicable to a certain tolerance of measurements (which is outlined at the beginning of the piece). When you stray from those paradigms what you're saying is correct, and Garry Holloway will be quick to point out that deeper pavilions can benefit from a degree of painting paired with a higher order of cut-precision.

 

[Karl_K]

I once made the statement that every RB ever cut and likely ever will be cut has some painting and digging present. No one has been able to prove me wrong. It is just the nature of cutting a super hard material with varying hardness and grain along with how diamonds are cut on a wheel.

100% correct. And who has tried to prove you wrong? ...I can only imagine it was a theorist, not anyone who has ever cut a diamond

It was lol

 

[Karl_K]

Garry Holloway will be quick to point out that deeper pavilions can benefit from a degree of painting paired with a higher order of cut-precision.

I agree with that also.
You can make the lower girdles shallower on a deeper pavilion and improve the overall cut quality.
This is rather a complex subject that can drive one batty once you get deep into it.

 

[Rhino]

TELL ME ABOUT IT

 

[lulu]

Sorry, I thought we were discussing artistic lingerie.