New HCA uses report #'s

[Garry H (Cut Nut)]

Hi all. We have done some up grades to HCA.
1. you can enter the GIA report # - most stones of the better cut available stones will come up with a simple cut and paste. If not then you just enter the data as usual
2. there is a new graphic for the grade bar
3. a new graphic that indicates where the stone falls withing GIA and likely AGS cut grades (remember this is based only on Table, crown and pavilion angle. Depth % enables us to calculate girdle thickness but we do not attempt to do GIA cut grades from girdle)
4. trade members are directed to a new commercial HCA site where they will receive a subscription service. That service enables uploading of 100,000 stones at a time. That should lead to Pricescope vendors being able to sift through and list the likely best new stones as they become available. PS vendors get a 50% discount.
5. there have been a lot of trade and affiliate buisnesses doing HCA for thousands of stones a month on the PS HCA site - so we decided to enable a trade only service (and charge for it)
6. if you are not logged in you will have a restricted number of searches
7. I removed the % data as it is way less accurate given GIA rounding is even worse on %'s than crown and pavilion angle rounding (culet was only useful when % were entered)
8. have a cool little GIF to explain why scores under 1.0 are great for earrings and pendants, and may not be best for rings
9. the data you last entered stays now rather than defaulting to 34 40.5. Opinions on changing default to Tolkowsky or 34 41?

I am open to suggestions that can improve the HCA service. It is in Beta 1.7

 

[OoohShiny]

Great work

The trade service sounds like an excellent idea!

re: point 9, I'm not sure it matters what numbers are in there, as they'll likely each be getting changed anyway!

 

[valeria101]

9. the data you last entered stays now rather than defaulting to 34 40.5. Opinions on changing default to Tolkowsky or 34 41?

Could the default be blanc ?

 

[metall]

I really like that we can just use the GIA number now! Thank you for the updates!

 

[whitewave]

It was cool to use the GIA numbers, thanks.

 

[Garry H (Cut Nut)]

You are all welcome.
Think if the defaaults were closer to numbers people often enter - it could save time. 61 34 41 for example are a frequently entered individual numbers and nice round numbers lowish and easy to add to.

 

[Karl_K]

kewl
I think tolk just to honor his work.
On the other hand I like 34/41/56t and it might help with those that bad mouth it.
But overall I think tolk would be best.

 

[John P]

kewl
I think tolk just to honor his work.
On the other hand I like 34/41/56t and it might help with those that bad mouth it.
But overall I think tolk would be best.

Selfishly speaking, for many years I've taught a class introducing HCA to jewelers in showrooms. The default of 40.5 PA has been robust for teaching. First, it illuminates how deep current productions have become. Second, it's a number that will never appear on reports because GIA would round it. Third, as a different taste-opinion, it really opens doors to discussion. After covering both worthy steep and shallow combinations, I introduce Tolkowski's historic angles as a central staple to remember.

For me, a default of 41 sends a dubious message. Some diamonds with 41 will be rounded from 41.1. That's over a third of a degree deeper than Master Tolk and more than a half-degree above Master Holloway's current default. I know it's only one number but that's quite a shift towards the deep.

Considering all of this, I'd like to see modern Tolk as default, for the same reason Karl cites: Historically, you will be giving tribute to a century of specificity, reinforced as worthy by all subsequent systems. Educationally, it will make your HCA a powerful classroom tool.

Bonus ask? As there is no easy instructional mnemonic for 56, 34.5, 40.75, I'd love to see the hundredth appear for PA, in the default view only.

Thank you for continuing to evolve a tremendous tool.

 

[Garry H (Cut Nut)]

Selfishly speaking, for many years I've taught a class introducing HCA to jewelers in showrooms. The default of 40.5 PA has been robust for teaching. First, it illuminates how deep current productions have become. Second, it's a number that will never appear on reports because GIA would round it. Third, as a different taste-opinion, it really opens doors to discussion. After covering both worthy steep and shallow combinations, I introduce Tolkowski's historic angles as a central staple to remember.

For me, a default of 41 sends a dubious message. Some diamonds with 41 will be rounded from 41.1. That's over a third of a degree deeper than Master Tolk and more than a half-degree above Master Holloway's current default. I know it's only one number but that's quite a shift towards the deep.

Considering all of this, I'd like to see modern Tolk as default, for the same reason Karl cites: Historically, you will be giving tribute to a century of specificity, reinforced as worthy by all subsequent systems. Educationally, it will make your HCA a powerful classroom tool.

Bonus ask? As there is no easy instructional mnemonic for 56, 34.5, 40.75, I'd love to see the hundredth appear for PA, in the default view only.

Thank you for continuing to evolve a tremendous tool.

Thx Karl and John,
Tolkowsky 61 57 34.5 40.8 is probably going to fix a lot of issues - comes in around 1.3

 

[John P]

Copy that. And thank YOU. May I respectfully suggest 61.5 56 34.5 40.7 - which comes in at a perfect 1

 

[Karl_K]

Copy that. And thank YOU. May I respectfully suggest 61.5 56 34.5 40.7 - which comes in at a perfect 1

that sounds kewl

 

[Garry H (Cut Nut)]

I did check and noted that (i cant memorize all combos) but think a number closer to mid 1 and 2 would help solve some under 1 questions and issues

 

[Lore]

8. have a cool little GIF to explain why scores under 1.0 are great for earrings and pendants, and may not be best for rings

Hi, and thanks for your update on this tool! Where can I find this GIF?

 

[psadmin]

Garry asked me to upload the gif.

We are still working out the explanations.

 

[RetroTreeGal]

I love her facial expressions!

 

[Garry H (Cut Nut)]

I love her facial expressions!

Thanks. Does it explain why stones under HCA 1.0 may not be suitable for rings. Still working on a method to show why under 1.0 work really well for earrings and pendants

 

[Lore]

My read of the image is that the closer she is to the ring, the more her head blocks light resulting in more contrast and a darker diamond. Am I reading that correctly? Does the diamond in the image have a <1.0 HCA?

Is there that big of a difference between a diamond at HCA 0.9 vs 1.0?

 

[RetroTreeGal]

Thanks. Does it explain why stones under HCA 1.0 may not be suitable for rings. Still working on a method to show why under 1.0 work really well for earrings and pendants

I think so, with a little bit of text explaining that’s what is being shown.

 

[Garry H (Cut Nut)]

This is a nice rings stone Tolkowsky proportions about HCA 1.5 viewed from 60, 30, 20 and 15cm which is approx 24, 12, 8 and 6 inches respectively, with the darker diamonds from very close up.
A stone with say a HCA of 0.5 would be one stone darker at the respective differences.

 

[Garry H (Cut Nut)]

Check out the default numbers folks

 

[whitewave]

Thanks. Does it explain why stones under HCA 1.0 may not be suitable for rings. Still working on a method to show why under 1.0 work really well for earrings and pendants

Is there a preferable range for stud earrings... or does this go back to the idea that shallower might be better for earring spread? Thanks,

 

[Garry H (Cut Nut)]

Is there a preferable range for stud earrings... or does this go back to the idea that shallower might be better for earring spread? Thanks,

Under 1. More than that is splitting hairs

 

[whitewave]

Thanks.

And in general, it is still that 1.8 is not better or worse than 1.3? Both merit further evaluation?

 

[gm89uk]

8. have a cool little GIF to explain why scores under 1.0 are great for earrings and pendants, and may not be best for rings

I don't believe HCA under 1 is the best way to identify shallow diamonds at risk of obstruction at close viewing. Sure there is a correlation but there many exceptions to the rule.
56/61/34/40.7 would give HCA 0.8. This is not at risk of obstruction like a 34/40.6.

On the flip side FICs with high crowns and low pavilions are at risk of obstruction on close viewing, and commonly score >1.5. eg 55/62.5 37/40.2.

Really you need a separate algorithm that can calculate angle of obstruction based on C/P/T with pseudoraytracing, then to simply outcome you should have a cut off point and something that clearly states (for simplicity) diamond suitable for rings/pendants, erings or both.

At the moment posters are often concerned that their ering scored less than 1, despite the proportions being as such that they would most likely be fine. The GIF is nice, but it won't change the fact that HCA<1.0 is not an accurate way to identify stones at risk of obstruction, or alleviate those concerns.

 

[Garry H (Cut Nut)]

Thanks.

And in general, it is still that 1.8 is not better or worse than 1.3? Both merit further evaluation?

OF COURSE. there are 4 functions and they compete

 

[Garry H (Cut Nut)]

I don't believe HCA under 1 is the best way to identify shallow diamonds at risk of obstruction at close viewing. Sure there is a correlation but there many exceptions to the rule.
56/61/34/40.7 would give HCA 0.8. This is not at risk of obstruction like a 34/40.6.

On the flip side FICs with high crowns and low pavilions are at risk of obstruction on close viewing, and commonly score >1.5. eg 55/62.5 37/40.2.

Really you need a separate algorithm that can calculate angle of obstruction based on C/P/T with pseudoraytracing, then to simply outcome you should have a cut off point and something that clearly states (for simplicity) diamond suitable for rings/pendants, erings or both.

At the moment posters are often concerned that their ering scored less than 1, despite the proportions being as such that they would most likely be fine. The GIF is nice, but it won't change the fact that HCA<1.0 is not an accurate way to identify stones at risk of obstruction, or alleviate those concerns.

Would you like to do a better job?
Steep Shallow stones have very small spreads and so do not work well for earrings and pendants. Any advantage they have in the fire department is more or less lost because the main attribute observers see is brightness and apparent size.

 

[whitewave]

Thanks, Garry.

 

[gm89uk]

Would you like to do a better job?

I am open to suggestions that can improve the HCA service. It is in Beta 1.7

Garry I am not mindly criticising your work, I apologise if it came across as so. I am responding as per your request where you stated you were open to suggestions.

Additionally with your expertise, I thought it would be neat if you could create something that would calculate obstruction. Being that you specifically mentioned it in an HCA suggestion thread I do not think I spoke out of place.

 

[Garry H (Cut Nut)]

Garry I am not mindly criticising your work, I apologise if it came across as so. I am responding as per your request where you stated you were open to suggestions.

Additionally with your expertise, I thought it would be neat if you could create something that would calculate obstruction. Being that you specifically mentioned it in an HCA suggestion thread I do not think I spoke out of place.

Obstruction is well covered by Dark Zone in HCA. Your example of a steep Deep is good GM, sorry for brief reply on phone that cam across ugly. Somewhere on Ideal-scope.com there is a lesson for cutters that small tables and steep deeps need to have very long lower girdles (85%+) to avoid the darkness which causes head obstruction over very long distances and even when seen from a bit of an angle (like shallow stones, but shallow stones almost never have small tables and very short lower girlde facets).
The main issue though is that shallow stones have bigger spreads by about an extra 3-5% of carat weight and steep deeps are a further 3-5% smaller (and compounded because shallow stones tend to be very thin to medium vs steep deeps being Slightly thick to very thick).
But steep deeps have more fire

 

[lalala]

Re: #5 are sure it's trade members or just loyal PS'ers? I know I try a few dozen or hundred a day