AGS less strict on colour?

[DejaWiz]

ok 1,6,7 How would you explain this to a PS newbie?

I have a very limited number of these and not in higher colors(d-z) so dont ask for an I :}
@yssie @DejaWiz @oncrutchesrightnow

Higher absorption of light in the blue and violet visible spectrum realm results in a perceived greater intensity of the remaining colors at the opposite ends of the spectrum, in this case the result is orange (yellow for the second spectrograph).
A blue diamond would be the opposite: higher absorption in the yellow-orange-red range resulting in higher perceived intensity at the blue-violet end of the spectrum.

 

[Karl_K]

Here is a ruby for comparison.

Its not a practical system but it is interesting.
I with I had more examples.

 

[DejaWiz]

Here is a ruby for comparison.

Its not a practical system but it is interesting.
I with I had more examples.

That makes perfect sense...blue and green are primarily absorbed, leaving mostly red and partially violet ranges to be visibility perceived.

 

[yssie]

Dang it @Karl_K. I’m legit jealous. Would love to get those done for a master grading set…

As for explaining it to newbies - I think I’ll go the route of waiting for Mr. Pollard to write something up in his excellent education sections

So now that we’re all seven agreed that we’re getting rid of colour grading as it’s done today… How shall the trade price stones using spectrophotometer output?

 

[Karl_K]

Dang it @Karl_K. I’m legit jealous. Would love to get those done for a master grading set…
me to!

As for explaining it to newbies - I think I’ll go the route of waiting for Mr. Pollard to write something up in his excellent education sections
rofl!!

So now that we’re all seven agreed that we’re getting rid of colour grading as it’s done today… How shall the trade price stones using spectrophotometer output?

hmm there is a big problem, take 5 diamonds all graded E today and they would have totally different curves if they were different tones.
Having grey,brown,yellow,pink, or blue tones would all result in different curves.

 

[yssie]

hmm there is a big problem, take 5 diamonds all graded E today and they would have totally different curves if they were different tones.
Having grey,brown,yellow,pink, or blue tones would all result in different curves.

Price those vaguely blue and pink Es higher than the vaguely yellow Es… I could see that actually. Chunk up the wavelength spectrum and the absorption intensity scale, and price according to the maxima on those absorption/wavelength plots. The pricing rubric would be long, since there are so many combinations, but it could be reasonably straightforward to automate the calculation…

Matching stones would be a breeze…

 

[Starstruck8]

Here is a ruby for comparison.

Its not a practical system but it is interesting.
I with I had more examples.

These are fascinating. I'm wondering how they are measured. Are they taken from a particular facet, or is there some sort of averaging? How are differing path lengths treated?

 

[Karl_K]

These are fascinating. I'm wondering how they are measured. Are they taken from a particular facet, or is there some sort of averaging? How are differing path lengths treated?

Tools used:

Spectrophotometry - Wikipedia

en.wikipedia.org

Most likely the sas2000 spectrophotometer by Martin Haske was used.
Most of the information on it has disappeared from the net but this remains:

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I do not know the specifics of which model and procedure was used.

 

[Starstruck8]

Tools used:

Spectrophotometry - Wikipedia

en.wikipedia.org

Most likely the sas2000 spectrophotometer by Martin Haske was used.
Most of the information on it has disappeared from the net but this remains:

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ProtectedPool ➤ Web3 Smart DeFi Wallet . Your New DeFi Experience:: Secure, Smart, Simple. Double Approvals. Add extra confirmation of any transaction with 2FA solutions including Google Authenticator or hardware security keys. Self-custodial Solutions. Protected Pool is built on smart...

docplayer.net

I do not know the specifics of which model and procedure was used.

Thank you for this. I was not able to read the linked article properly, only the unformatted text, without the tables and illustrations. So I could not make much of it.

What I was not clear about is what the plotted 'absorption' represents. Is it 'absorption cofficient' (i.e. with dimension length^(-1))? This seems like it would be non-trivial to measure for an irregular object. Or is it something like 1 - reflectance? This seems like it would depend on the the facet and the path length, or else be some sort of average.

But either way, the pictures are cool.

 

[Karl_K]

Thank you for this. I was not able to read the linked article properly, only the unformatted text, without the tables and illustrations. So I could not make much of it.

What I was not clear about is what the plotted 'absorption' represents. Is it 'absorption cofficient' (i.e. with dimension length^(-1))? This seems like it would be non-trivial to measure for an irregular object. Or is it something like 1 - reflectance? This seems like it would depend on the the facet and the path length, or else be some sort of average.

But either way, the pictures are cool.

There are a lot of unknowns to me about them and the curves are actually for making colored diamond models not grading.
For example:

 

[Karl_K]

Here is a pear with a lot of long light paths using the same color as above. So its obvious that some weighting or averaging or just selecting an area went on with the original stone.


edit: to turn it into a full blown grading system would take a lot of complex work.

 

[Starstruck8]

There are a lot of unknowns to me about them and the curves are actually for making colored diamond models not grading.
For example:

Yes, that makes sense. Thank you for explaining. The curves are presumably absorption coefficients. These can be applied to a theoretical model diamond to calculate its appearance in some simulated lighting. As inputs to a theoretical model, they can be whatever you like. How they might be measured for an actual stone is a different issue...

 

[Texas Leaguer]

Universal automated color grading is certainly a worthy goal, but as we see being hashed out in this thread there are a whole range of complicating factors to making this a reality.

Several years ago GIA did confirm that they were doing some color grading entirely by machine, BUT on a very limited subset of diamonds. Presumably, the instrument they are developing had proven to be accurate and consistent when used on diamonds with a narrow range of characteristics. As I recall at the time, they were doing automated color grading on smaller size round, non-fluorescent diamonds in the normal range with yellow hue. I do not know if they have expanded the range since then but I will try to find out.

In answer to @Rockdiamond 's question, I did confirm that AGSL does not do any automated grading and still use the same grading methods and master stones.

Personally, I would rather see GIA implement a transparency metric on their reports, and there is a suggestion in the recent GIA study on fluorescence that their contrast analysis approach might enable such reporting in the future. To me this is a more worthwhile project for GIA. It seems likely to be more straight forward and technically feasible, and it would provide important information to consumers. Currently, consumers are pretty much unaware that there are differences in transparency between diamonds, and those differences have implications for light performance. While consumers agonize over technical differences between diamonds, they are sometimes oblivious to differences which have far greater impacts to overall beauty, including color differences.

 

[oncrutchesrightnow]

ok 1,6,7 How would you explain this to a PS newbie?

I have a very limited number of these and not in higher colors(d-z) so dont ask for an I :}
@yssie @DejaWiz @oncrutchesrightnow

What, if any, are the inclusions?

 

[oncrutchesrightnow]

hmm there is a big problem, take 5 diamonds all graded E today and they would have totally different curves if they were different tones.
Having grey,brown,yellow,pink, or blue tones would all result in different curves.

THIS. Not everyone prefers yellow.

[…]

Personally, I would rather see GIA implement a transparency metric on their reports, and there is a suggestion in the recent GIA study on fluorescence that their contrast analysis approach might enable such reporting in the future. To me this is a more worthwhile project for GIA. It seems likely to be more straight forward and technically feasible, and it would provide important information to consumers. Currently, consumers are pretty much unaware that there are differences in transparency between diamonds, and those differences have implications for light performance. While consumers agonize over technical differences between diamonds, they are sometimes oblivious to differences which have far greater impacts to overall beauty, including color differences.

So would it be a map or an average score?

 

[Karl_K]

What, if any, are the inclusions?

its fl like most computer generated diamonds of course.

 

[AllAboardTheBlingTrain]

Bringing the discussion back to the table on pricing differences between labs that was posted on the first page, for a second…

As a non US based customer, this actually makes me pause when I see an AGS cert, because it seems like AGS is/can be a bit softer on colour than GIA and it sells at a premium to GIA anyway. I understand this premium is probably borne out by the general better cut quality of the AGS stone, but I also feel if I were to ever sell my stone I’d take a bigger haircut since I’d have to get it recerted by GIA to sell in my market and the retail price of my stone will be 15-odd% less than what I paid (taking in account colour difference and cut premium). I feel less uncertain about purchasing something like HRD, which trades at a discount to GIA anyway, is reasonably well respected in my market so will stand alone / not require recertification, and even if it is recerted and does come back lower by one grade, the retail price of my stone as per GIA will be closer to the price I paid thanks to the discount on HRD stones.

I do think the trade off for US based customers is probably less strong, since AGS is a widely accepted cert there. And those who value cut quality above all else will continue to purchase AGS stones.

 

[yssie]

One of the draws of AGS - from vendor and customer perspective - is that they’ll customize their reports for specific brands. A vendor can get their company name and logo on the report itself. GIA’s not going to do that. GIA’s not even going to entertain the idea. And a consumer can insure with that brand on the report itself, thereby further guaranteeing replacement with truly “like kind and quality”.

The downside of this willingness to customize is that - from the consumer perspective - it adds yet more confusion to the already-thoroughly-confusing smorgasbord of AGSL report types.

 

[LilAlex]

60% AGS+GIA same grade

40% AGS graded higher

I have not read all the posts but, statistically speaking, this is a remarkable difference between the two labs

 

[Karl_K]

I do not like the customized reports.
Im going to try and be very careful, this is about appearances not that I have any evidence of wrong doing by anyone using those reports or AGSL.
I dislike them for the same reason I very strongly dislike the advertising of diamond brands put on the AGS Laboratories facebook page.
In my opinion they give the "appearance" of impropriety.

 

[max1111]

Bringing the discussion back to the table on pricing differences between labs that was posted on the first page, for a second…

As a non US based customer, this actually makes me pause when I see an AGS cert, because it seems like AGS is/can be a bit softer on colour than GIA and it sells at a premium to GIA anyway. I understand this premium is probably borne out by the general better cut quality of the AGS stone, but I also feel if I were to ever sell my stone I’d take a bigger haircut since I’d have to get it recerted by GIA to sell in my market and the retail price of my stone will be 15-odd% less than what I paid (taking in account colour difference and cut premium).

This is my issue with the whole thing. Blogs and forums push AGS as a better lab that is worth the small premium but it's not really a small premium if they are rounding up on colour.

6% premium for AGS can very quickly turn into 20%+ if you're really buying a colour grade below.

You could easily end up 2 grades below your starting point by trading colour for cut and GIA for AGS..

 

[max1111]

I do not like the customized reports.
Im going to try and be very careful, this is about appearances not that I have any evidence of wrong doing by anyone using those reports or AGSL.
I dislike them for the same reason I very strongly dislike the advertising of diamond brands put on the AGS Laboratories facebook page.
In my opinion they give the "appearance" of impropriety.

Who is AGS really here to serve, customers or vendors?

I'm not sure it's possible to be truly customer focussed when you're a smaller company and vendors make up the majority of your income. If they were customer focussed they should be more strict.

It's like when a magazine reviews an advertisers product. It's never going to be bad is it?!

Reading between the lines I feel that AGS really exists to extract more value for vendors. Part of that is soft colour grading.

I'd love someone to prove me wrong here..

 

[yssie]

AGS is an honest, ethical, and upstanding operation. They’ve been at the forefront of research for as long as they’ve existed and their good reputation is earned and deserved.

In terms of colour grading, as Karl and others have explained, they - every other lab - are chasing the gold standard, and GIA itself is a moving target. It would be both pointless and suicidal to earn a reputation for grading more harshly than GIA. What purpose would that serve? Contrary to your bolded, that certainly doesn’t benefit the customer - the customer is still left confused about what colour grading means and what GIA would say. IMO AGS has done a better job than any other (non-GIA) major lab of both keeping pace with GIA and keeping their operations clean and customer-focused.

Are they perfect? No. But neither is GIA itself. And there’s a really easy solution to the “problem” of not knowing what GIA would say - just send the stone to GIA. You can do it yourself. If knowing what GIA would say is important to you prior to purchase, then that’s easy too - just choose your vendor accordingly. The fact that those us who acknowledge that AGS cannot keep perfect pace with GIA on colour grading have and will happily purchase stones with AGS reports (only AGS reports) at retail pricing is the most meaningful “proof” possible, no? There are many labs that are truly out to bamboozle customers and muddy the industry’s reputation, AGS is not and will never be one of them. They have my respect. So does GIA.

You can take all of our opinions in this thread at face value, no reading between lines needed. There are no skeletons in this closet

 

[DejaWiz]

AGS is an honest, ethical, and upstanding operation. They’ve been at the forefront of research for as long as they’ve existed and their good reputation is earned and deserved.

In terms of colour grading, as Karl and others have explained, they - every other lab - are chasing the gold standard, and GIA itself is a moving target. It would be both pointless and suicidal to earn a reputation for grading more harshly than GIA. What purpose would that serve? Contrary to your bolded, that certainly doesn’t benefit the customer - the customer is still left confused about what colour grading means and what GIA would say. IMO AGS has done a better job than any other (non-GIA) major lab of both keeping pace with GIA and keeping their operations clean and customer-focused.

Are they perfect? No. But neither is GIA itself. And there’s a really easy solution to the “problem” of not knowing what GIA would say - just send the stone to GIA. You can do it yourself. If knowing what GIA would say is important to you prior to purchase, then that’s easy too - just choose your vendor accordingly. The fact that those us who acknowledge that AGS cannot keep perfect pace with GIA on colour grading have and will happily purchase stones with AGS reports (only AGS reports) at retail pricing is the most meaningful “proof” possible, no? There are many labs that are truly out to bamboozle customers and muddy the industry’s reputation, AGS is not and will never be one of them. They have my respect. So does GIA.

You can take all of our opinions in this thread at face value, no reading between lines needed. There are no skeletons in this closet

 

[Texas Leaguer]

Who is AGS really here to serve, customers or vendors?

Both. Just like GIA. And just like the other major labs.

There is not an inherent conflict of interest between the consumer and the trade with respect to laboratory grading. The availability of accurate information increases consumer confidence and leads to more sales. A classic win/win.

And it behooves every lab to maintain a reputation for dependability, otherwise consumers and trade both lose trust and curtail or stop using their services. The problems EGL has had over the years is an example.

 

[max1111]

It would be both pointless and suicidal to earn a reputation for grading more harshly than GIA. What purpose would that serve? Contrary to your bolded, that certainly doesn’t benefit the customer - the customer is still left confused about what colour grading means and what GIA would say.

AGS ideal is a smaller range than GIA EX, that wasn't suicide was it?

For a consumer it'll never be a bad thing to have an appraiser that is slightly more strict than the industry standard, that guarantees that they will never get less than expected. Porsche 111 point inspection vs generic inspection.

Obviously the correct solution is that they need to be much closer to GIA and when borderline favour the consumer and grade conservatively. The current situation is that the AGS is more accurate in one aspect but less so in the one that can have the biggest impact on price.

Are they perfect? No. There’s a really easy solution to the “problem” of not knowing what GIA would say - just send the stone to GIA. And if knowing what GIA would say is important to you prior to purchase, then choose your vendor accordingly.

As far as I can see none of the current super-ideal vendors dual certify. If they did they would have to use the GIA grade for colour and AGS for cut. It's a shame the HPD thing didn't work out as that was about as transparent as you can get.

The fact that those us who acknowledge that AGS cannot keep perfect pace with GIA on colour grading have happily purchased stones with AGS reports (only AGS reports) is the most meaningful “proof” possible, no?

Not really as there are all sorts of cognitive biases involved with high value enthusiast purchases. Some can obviously justify the premium of needing to buy a colour higher. That is fine.

 

[Texas Leaguer]

I do not like the customized reports.
Im going to try and be very careful, this is about appearances not that I have any evidence of wrong doing by anyone using those reports or AGSL.
I dislike them for the same reason I very strongly dislike the advertising of diamond brands put on the AGS Laboratories facebook page.
In my opinion they give the "appearance" of impropriety.

Just to be clear, most major labs do provide a service for issuing branded reports.

Companies have to provide proof of legal ownership of the registered brand, and brand characteristics (to the extent it has rigid requirements). The company can then order a branded report, and if the diamond conforms to those parameters the lab will issue the proprietary report.

I'm not a watch guy, but I think you can look at it like an appraisal on a brand name watch. If it is authenticated by the appraiser, it is stated to be a genuine product of that brand.

 

[yssie]

As far as I can see none of the current super-ideal vendors dual certify. If they did they would have to use the GIA grade for colour and AGS for cut. It's a shame the HPD thing didn't work out as that was about as transparent as you can get.

100%. Unfortunately I think it did also raise price non-trivially.

One could argue that vendors of precision-cut stones don’t need the AGS cut grade at all, and could just use GIA alone, since those vendors provide all sorts of scans and imaging that conveys everything that AGS’ cut grade does plus more. But choosing the AGS report anyway achieves four goals:
1. It provides independent assurance of cut quality
2. It provides proof of cut quality in a way that doesn’t require becoming an expert in #DiamondThings to understand
3. It allows consumers to insure with a branded report
4. It ensures the market doesn’t converge on GIA as an unquestioned monopoly

So I can understand the choice, especially since there are workarounds for consumers who do want the GIA opinion as well. For anyone who wants to purchase a branded stone that’s got an AGS report and wants a GIA report as well - I would encourage them to reach out to their vendors of interest, and perhaps something could be worked out.

FWIW I’ve got three rose cut pears with GIA reports, and GIA called all three “modified pear brilliants”. My vendor and I just laughed.

 

[max1111]

100%. Unfortunately I think it did also raise price non-trivially.

I assume that's because people were actually getting what they paid for!

One could argue that vendors of precision-cut stones don’t need the AGS cut grade at all, and could just use GIA alone, since those vendors provide all sorts of scans and imaging that conveys everything that AGS’ cut grade does plus more. But choosing the AGS report anyway achieves four goals:
1. It provides independent assurance of cut quality
2. It provides proof of cut quality in a way that doesn’t require becoming an expert in #DiamondThings to understand
3. It allows consumers to insure with a branded report
4. It ensures the market doesn’t converge on GIA as an unquestioned monopoly

In theory yes it's a one stop shop for those that did a google search rather than hit the mall. The problem is you're not quite getting what you paid for if we accept GIA is the industry standard.

 

[max1111]

Both. Just like GIA. And just like the other major labs.

There is not an inherent conflict of interest between the consumer and the trade with respect to laboratory grading. The availability of accurate information increases consumer confidence and leads to more sales. A classic win/win.

And it behooves every lab to maintain a reputation for dependability, otherwise consumers and trade both lose trust and curtail or stop using their services. The problems EGL has had over the years is an example.

Assuming AGS were able to match GIA for colour would they do it?

Or,

Would they lose the vendors who rely on them to go soft on colour?