What is transitional cut?

[coatimundi_org]

Date: 1/27/2009 12:22:02 PM
Author: strmrdr
Is not that far behind a ideal cut RB in light return and in some lighting will beat it.

But the RB will likely be better balanced across multiple lighting conditions.

That is not to say you wouldn''t prefer the trans even when it technically isn''t performing at as high a level as the RB.

Interesting--I think the trans perform like the rbs, but a hair better. Are my eyes deceiving me? haha--off to experiment...

 

[strmrdr]

Date: 1/27/2009 12:38:49 PM
Author: coatimundi

Date: 1/27/2009 12:22:02 PM

Author: strmrdr

Is not that far behind a ideal cut RB in light return and in some lighting will beat it.


But the RB will likely be better balanced across multiple lighting conditions.


That is not to say you wouldn''t prefer the trans even when it technically isn''t performing at as high a level as the RB.

Interesting--I think the trans perform like the rbs, but a hair better. Are my eyes deceiving me? haha--off to experiment...

Hard to say without looking but your eyes may prefer the patterns in the trans...
overall light return is almost certainly down slightly in some lighting compared to the RB, the short lgf% forces that trade off.

 

[that_someone_special]

WOW thanks so much for the pictures.. I was a bit confused myself, and the pictures really point out the difference. You''re so helpful. They should put a big gold star next to your name, strmrdr!

 

[strmrdr]

Date: 1/27/2009 12:35:45 PM
Author: coatimundi

Date: 1/27/2009 11:40:23 AM

Author: strmrdr

Date: 1/27/2009 1:13:00 AM


Author: strmrdr


The amount of fire is more dependent on the lgf% than the crown height with RB style diamonds.

That should say style and apparent amount.


A higher crown can shift a RB towards the fire side but doesn''t change the overall appearance as much as changes to the lgf%


As you can see below moving from a TIC to a FIC there are relatively small changes to the virtual facets compared to going from the tic to a transitional shown earlier.

The FIC in your rendering has a slightly smaller pa and slightly shorter lgfs. This type of analysis is making more sense to me vs. the smaller table higher crown idea. I studied 200 rbs in class for fire and brilliance--not as many as you, of course --but enough to see that smaller table-higher crown did not always produce more fire by default.


Now, as I pay more attention to lgfs, I''m seeing new things.


I''m going to snap some comparison shots in various lighting conditions--will post later. The ACA has 78% lgfs, and I have a much larger rb that has 80% lgfs with a 40.8pa and 34.1ca with a 57%table--that is very firey.


Thanks for your response Storm!

The fic has the same lgf%, a steeper crown, shallower pavilion and a smaller table.
Thais is where lgf% gets tricky and why some lgf% work with some combos and not others.
That is way beyond what I can cover here.
The biggest problem in learning on live stones is seeing enough of them in enough different lighting at the same time.
That is where virtual diamonds are nice, you can learn then compare what you expect to see with what you are seeing.

 

[that_someone_special]

Sooo.. I wrote in another thread that last week or so someone gave me a diamond (for free!!) and said it was an OEC. It''s small and slightly shallow in cut (compared to the real OEC that I have) but once I got my loupe out and looked at it.. I was stumped.

I just louped it, AGAIN, like 2 mins ago and compared it to a RB I have, and the diagram you posted. OK. It I am 98% sure it''s a transitional cut that is slightly on the more shallow side. How fun! I love diamonds!

Thanks for the help!

 

[coatimundi_org]

Date: 1/27/2009 12:58:52 PM
Author: strmrdr

The fic has the same lgf%, a steeper crown, shallower pavilion and a smaller table.

Thais is where lgf% gets tricky and why some lgf% work with some combos and not others.

That is way beyond what I can cover here.

The biggest problem in learning on live stones is seeing enough of them in enough different lighting at the same time.

That is where virtual diamonds are nice, you can learn then compare what you expect to see with what you are seeing.

Yah, that is involved. There are a myriad of combinations--that is why I don''t always subscribe to the idea of finite measurement, and also why I love old stones. They "perform" in unimaginable ways--defy odds--these trans do. There are textbook combos that absolutely don''t work--steep deep, fish eye, etc., but there are combos that do fall out of the realm of "ideal" that can work--performance wise. I think the older stones exemplify that.

Thanks for the fantastic virtual visuals.

Another thing about photographing stones in different lighting is that the camera will never capture what I see--frustrates me to no end...

 

[strmrdr]

Date: 1/27/2009 1:07:01 PM
Author: swedish bean
Sooo.. I wrote in another thread that last week or so someone gave me a diamond (for free!!) and said it was an OEC. It''s small and slightly shallow in cut (compared to the real OEC that I have) but once I got my loupe out and looked at it.. I was stumped.

I just louped it, AGAIN, like 2 mins ago and compared it to a RB I have, and the diagram you posted. OK. It I am 98% sure it''s a transitional cut that is slightly on the more shallow side. How fun! I love diamonds!

Thanks for the help!

Your welcome!
Have you or can you post a picture? I would love to see it.

 

[strmrdr]

Date: 1/27/2009 1:11:25 PM
Author: coatimundi

Yah, that is involved. There are a myriad of combinations--that is why I don''t always subscribe to the idea of finite measurement, and also why I love old stones. They ''perform'' in unimaginable ways--defy odds--these trans do. There are textbook combos that absolutely don''t work--steep deep, fish eye, etc., but there are combos that do fall out of the realm of ''ideal'' that can work--performance wise. I think the older stones exemplify that.


Thanks for the fantastic virtual visuals.


Another thing about photographing stones in different lighting is that the camera will never capture what I see--frustrates me to no end...

I agree with you some old cuts just have a magical quality to them that just works.
There are many that don''t just like today''s stones but when it does work they are sweet.

 

[that_someone_special]

I erase everything I said about being 98% sure. I''m looking at my pictures and thinking... eh... are those... what IS THIS THING? This picture looks like it has a culet but its a reflection I think.. (shallow diamond). It absolutely doesn''t have a culet. I DO know that. It''s just that compared to the RB I have, this one has less facets, yet more than the OEC.. soo...?? This is the best pic I could get- now batteries are dead. I''ll post another one in a min too. This is with my hand shading the light too.

 

[that_someone_special]

And this looks like a RB to me.. I think? because of the shape of the facets.. I guess... (and this is the same diamond from above) It is really wide compared to it's height too... which is why I'm calling it shallow.

I know these pics are bad-- its the best I can do right now! And thanks for your help.

 

[chrono]

SB, the stone looks very modern-ish. I don't see the "flower" pattern and actually see some arrowheads.

 

[that_someone_special]

I know, the pictures look like that, and I was basing this off of what it looked like compared to some other stones. I might try better pictures later. It''s just a tiny diamond but fun to look at anyways...

 

[strmrdr]

looks like a nailhead but cant tell the vintage....

 

[glitterata]

Karl, maybe you''ve answered this question, but I''m still a bit confused: Why don''t they cut short lgf%s nowadays to produce something with similar proportions to a modern brilliant, but with the broader virtual facets of a transitional cut? It wouldn''t cost more, would it? And lots of us would prefer the look, right?

 

[strmrdr]

Date: 1/28/2009 2:26:16 PM
Author: glitterata
Karl, maybe you've answered this question, but I'm still a bit confused: Why don't they cut short lgf%s nowadays to produce something with similar proportions to a modern brilliant, but with the broader virtual facets of a transitional cut? It wouldn't cost more, would it? And lots of us would prefer the look, right?

Scared to do something different, expense in creating a market, dealer education, volume and pricing.
Lighting plays a part also but that is changing!
I would be very easy for someone like say Paul to cut to the same specs he currently does but with 60-65% lgf% to create a transitional like cut.
They would have to cost the same as the ags0 cuts he now sells.
The big question is would they sell?

 

[coatimundi_org]

Date: 1/28/2009 2:34:48 PM
Author: strmrdr


Scared to do something different, expense in creating a market, dealer education, volume and pricing.

Lighting plays a part also but that is changing!

I would be very easy for someone like say Paul to cut to the same specs he currently does but with 60-65% lgf% to create a transitional like cut.

They would have to cost the same as the ags0 cuts he now sells.

The big question is would they sell?

I think they would if they had the fierce marketing of H&A, but we're so inundated with H&A now, that it would be an uphill battle. So many getting engaged want the romance of hearts and arrows.

I think it would take a long time, but if they were sold on romance--could work. My eye lurves 'em.

How well do Cushettes, Jubilees, and other different cuts sell? Couldn't nouveau trans cuts be added to the mix? Chunky rounds.

 

[stone-cold11]

Will the small LGF of such a cut still be able to obtain a AGS0? I have no idea what kind of matrix determines the performance cut grade of AGS.

 

[glitterata]

I''d buy them in a heartbeat! If I were buying a diamond, that is.

 

[diagem]

Date: 1/28/2009 2:26:16 PM
Author: glitterata
Karl, maybe you''ve answered this question, but I''m still a bit confused: Why don''t they cut short lgf%s nowadays to produce something with similar proportions to a modern brilliant, but with the broader virtual facets of a transitional cut? It wouldn''t cost more, would it? And lots of us would prefer the look, right?

Its being done..., not necessarily in the AGS "ideal" faceting angle combination..., but its being done...

I realy dont understand why none of the PS vendors try to fill these numerous requests..., maybe its not requested.

 

[coatimundi_org]

Date: 1/28/2009 2:58:15 PM
Author: glitterata
I''d buy them in a heartbeat! If I were buying a diamond, that is.

I would too! ...but there is something so nifty about scoring an old one. I like the imperfect charm. Technical perfection has never been my thing.

 

[glitterata]

DiaGem, please say more. Who''s doing it? Who buys the resulting stones?

Coati, I agree--the romance of the past is really strong for me. But I would still love a perfectly cut new transitional diamond.

 

[strmrdr]

Date: 1/28/2009 2:51:26 PM
Author: Stone-cold11
Will the small LGF of such a cut still be able to obtain a AGS0? I have no idea what kind of matrix determines the performance cut grade of AGS.

no it wouldn''t it would be under the cut off.

 

[Eva17]

storm,

is this stone a modern example of how the lgf''s would be to get the look of the middle of the transitional. They seem much fatter.....

 

[strmrdr]

Date: 1/30/2009 4:37:40 PM
Author: Eva17
storm,


is this stone a modern example of how the lgf''s would be to get the look of the middle of the transitional. They seem much fatter.....

not really....
I will post some more images later....
I also have some more info on the history I will share in the future.
Right now I''m digesting it.

 

[strmrdr]

This is fugly with a way to shallow pavilion but I made it so you can see the patterns the short lgf% make.
With better angles they would not be as dark but the same general shape.

 

[Eva17]

thanks karl!


so it is shaped more like a start and not like petals of a flower?

 

[strmrdr]

Date: 2/2/2009 12:45:02 PM
Author: Eva17
thanks karl!



so it is shaped more like a star and not like petals of a flower?

It depends on the exact lgf%, the angles and most importantly the degree of obstruction what it looks like in real life.
The most technically correct shape is the star for a symmetrical stone but you might not see it like that in a real stone except under controlled lighting and a set distance designed to bring it out and also real vintage stones are rarely symmetrical to a degree the best of modern RBs are.
So there are many variables.

fyi: I''m working on an article based on Al Gilbertson''s book that is going to be mind blowing when it comes to old cuts and what they should be called.
The term transitional is almost totally bogus marketing and even oec can be misleading.

 

[Eva17]

looking forward to reading it.

will you let us know when you are done with the article?

 

[strmrdr]

Date: 2/2/2009 1:28:11 PM
Author: Eva17
looking forward to reading it.


will you let us know when you are done with the article?

will do, it is going to be a few weeks.