Do well cut stones go dark?

[strmrdr]

Date: 2/23/2008 3:21:36 PM
Author: coatimundi
Thank YOU Strmrdr! This is much fun for me.

Oh and I meant to say that the oval showed more ''fire and scintillation'' under the tree not ''fire and brilliance'' I edited that in my above post.

dispersion is the word your looking for :}
http://www.google.com/search?num=100&hl=en&defl=en&q=define:dispersion&sa=X&oi=glossary_definition&ct=title
Which is another facet of this discussion.
back later.

 

[coatimundi_org]

Date: 2/23/2008 3:25:48 PM
Author: strmrdr

Date: 2/23/2008 3:21:36 PM

Author: coatimundi

Thank YOU Strmrdr! This is much fun for me.


Oh and I meant to say that the oval showed more ''fire and scintillation'' under the tree not ''fire and brilliance'' I edited that in my above post.

dispersion is the word your looking for :}

http://www.google.com/search?num=100&hl=en&defl=en&q=define:dispersion&sa=X&oi=glossary_definition&ct=title

Which is another facet of this discussion.

back later.

Oh, thanks! A storm is rolling in. I wanted to get some closeups to better illustrate. Maybe I can get some later or tomorrow.

 

[diagem]

Date: 2/23/2008 2:50:42 PM
Author: strmrdr

Date: 2/23/2008 2:30:15 PM
Author: coatimundi


One more question. Are you speaking solely of rbs? or all cuts? Wondering because my oval operates entirely differently than my rb. I know it''s because the faceting is different, but also, I don''t think my oval is cut as well as my rb. If they were cut equally for brilliance, would they perform the same?

The oval does best in soft diffused lighting, but not so hot in bright sunlight. My oval hates the floodlights in the back alley.

The rb seems to do well all around, though it goes darker in sunlight(I know why now, so that''s no problem)

I actually wear the oval when I know I''ll like the lighting. The rb is an any place any time sort of stone.

eta: just took my oval and rb out in the backyard for a test. It''s 11:30am here in Venice Beach and sunny. They were both super sparkly and blinding! hmmm now I''m wondering about brilliance, sunlight, and time of day

all cuts that produce bright flashes, any reflector not just diamonds actually.
Rounds tend to return the light in a smaller area so it shows the effect more.
ie: more beams striking the eye.
The more intense the light return the more the eyes adjust.
But,,,
small intense light sources affecting only a small part of the eye might not trigger the response.
The more areas of the eye receiving bright flashes the faster and the more it responds.
Small intense flashes will damage the eye quicker than brighter larger flashes because the small flashes don''t trigger the protection reactions.

Your backyard study shows that bright direct lighting makes judging between diamonds impossible.
Move under a tree and you will see a far greater difference.

While your on this subject storm..., the 27% tabled Asscher performs incredibly well in direct sunlight..., as bright as can be

 

[strmrdr]

Date: 2/23/2008 4:17:34 PM
Author: DiaGem
While your on this subject storm..., the 27% tabled Asscher performs incredibly well in direct sunlight..., as bright as can be

I bet it does yummy!!!!

 

[strmrdr]

This is a good example of dynamic range...
The blue arrows point too where the camera adjusted its exposure too.
The red arrows show where the brightness and darkness exceeded the cameras dynamic range and details were lost in a white glob or a black glob.
The eyes do the same thing but have a much more variable range and fast switching.
As you move your eyes over this scene the exposure point for the eyes would change.
As the eyes rested on the diamonds and stopped moving the midpoint would be set based on the brightest elements in that area, thus putting the diamond body on the edges of the dynamic range making it appear darker.

edit: the low dynamic range of your monitor and limited brightness make this impossible too duplicate in images.

 

[strmrdr]

Date: 2/23/2008 3:09:58 PM
Author: coatimundi

The oval showed more fire and scintillation where the facets are the largest in the center and sides of the stone. The round seemed uniform.

Light return from large chunky facets that isn''t broken up into smaller chunks(larger virtual facets) is perceived as colored more than smaller brighter chunks of the same color.
This has several causes, 1: the different light receptors in the eyes coming into play 2: dynamic range and clipping just like in the photo. 3: large facets are more likely too act like a prism and break the light up.

This is why an oec appears too return more colored light than an RB with long lgf%.

But it isn''t that simple and that''s where I think the current studies are falling down.
Multiple small points of light can combine and form colored light.
This is where Marty is going with his spatial colors from chunky symmetrical stones.
Stones returning smaller light rays or with less symmetry get more mixing.
Is it important at normal viewing distances? Not really in my opinion.
Does it exist?.. yes likely.. is it interesting? yes.. is it a reason to buy one stone over another? No

Which part of your oval is prettier the parts returning small chunks or large? (small or large virtual facets)
For me the answer would be both in different ways.
2 personalities of light return in one stone.
That is the danger of using virtual facet size too call one diamond bad and one good it doesnt work :}

 

[strmrdr]

now that you have read this far you might be thinking what about a fic?
It has fairly small facets and small virtual facets yet it has a lot of fire.
Doesn''t that contradict what I am saying here?
Nope it doesn''t what it shows that the explanation so far doesn''t have enough variables and is too simple. :}

There are more than one way too produce fire in a diamond.
1: is chunky facets (both real and virtual)
2: bend the light more thru a high crown and increase dispersion or in simple terms spread the light return out while bending it more too separate the colors.

Trying too take both of those into account in a diamond grading system while taking into account vision and the perception of light is a daunting task, add in motion and it becomes a billion times more complicated.
A brightness metric like the ASET and IS provides is simple.
Nailing fire and scintillation is much more complex check back in 20 years for the answers :}

 

[strmrdr]

I wanted too say thank you this thread and the asscher design threads are the most fun I have had on PS in a long time!

 

[coatimundi_org]

Date: 2/23/2008 5:56:03 PM
Author: strmrdr

Date: 2/23/2008 3:09:58 PM

Author: coatimundi


The oval showed more fire and scintillation where the facets are the largest in the center and sides of the stone. The round seemed uniform.

Light return from large chunky facets that isn't broken up into smaller chunks(larger virtual facets) is perceived as colored more than smaller brighter chunks of the same color.

This has several causes, 1: the different light receptors in the eyes coming into play 2: dynamic range and clipping just like in the photo. 3: large facets are more likely too act like a prism and break the light up.


This is why an oec appears too return more colored light than an RB with long lgf%.


But it isn't that simple and that's where I think the current studies are falling down.

Multiple small points of light can combine and form colored light.

This is where Marty is going with his spatial colors from chunky symmetrical stones.

Stones returning smaller light rays or with less symmetry get more mixing.

Is it important at normal viewing distances? Not really in my opinion.

Does it exist?.. yes likely.. is it interesting? yes.. is it a reason to buy one stone over another? No


Which part of your oval is prettier the parts returning small chunks or large? (small or large virtual facets)

For me the answer would be both in different ways.

2 personalities of light return in one stone.

That is the danger of using virtual facet size too call one diamond bad and one good it doesnt work :}

I like both the small chunks and the large. The small facets give off a glittering/shimmery effect that seems present in most light sources. The larger chunkier facets are dynamic in some light. Sometimes they do go dark, but it's a tradeoff. I think with an oval one has to be a little more forgiving than with a round, as a result of this combination of faceting.

The round is a no brainer really. It always pleases my eye.

The oval is complicated, and there is something to be said about that. More challenging. I can stare at it for a long time.

Thanks Strmrdr for pointing those examples of dynamic range. This is most fascinating to me!

You are a great help, and I appreciate your explanations.

I am of the philosophy that the beauty of a diamond is solely for the beholder. I do appreciate numbers, especially for rounds, as guidelines. Always, though, it's the stone that speaks to my eye that wins. This is what I've gleaned so far, as I'm still a beginner!

eta: The round is a K color and the oval is a G. I am least interested in color, but I thought I'd add in case anyone wondered

 

[strmrdr]

Date: 2/23/2008 6:45:28 PM
Author: coatimundi


I like both the small chunks and the large. The small facets give off a glittering/shimmery effect that seems present in most light sources. The larger chunkier facets are dynamic in some light. Sometimes they do go dark, but it''s a tradeoff. I think with an oval one has to be a little more forgiving than with a round, as a result of this combination of faceting.

The round is a no brainer really. It always pleases my eye.

The oval is complicated, and there is something to be said about that. More challenging. I can stare at it for a long time.

Thanks Strmrdr for pointing those examples of dynamic range. This is most fascinating to me!

You are a great help, and I appreciate your explanations.

I am of the philosophy that the beauty of a diamond is solely for the beholder. I do appreciate numbers, especially for rounds, as guidelines. Always, though, it''s the stone that speaks to my eye that wins. This is what I''ve gleaned so far, as I''m still a beginner!

eta: The round is a K color and the oval is a G. I am least interested in color, but I thought I''d add in case anyone wondered

your welcome.
Id love too see and discuss more pictures of your lovely diamonds as you get time and light conditions too take them.

The goal of the numbers is too help design diamonds that look good.
Sometimes that gets turned around and the numbers try and define what looks good.
That level is not here yet and wont be for a long time.

 

[coatimundi_org]

Id love too see and discuss more pictures of your lovely diamonds as you get time and light conditions too take them.


The goal of the numbers is too help design diamonds that look good.

Sometimes that gets turned around and the numbers try and define what looks good.

That level is not here yet and wont be for a long time.

It's cloudy now so I'm going to go out back and take a few shots in this lighting condition, and then I'll do some indoor lighting shots. If the sun comes out tomorrow, I'll try for different sun shots. Maybe at the beach. I'll be posting soon. Yay Saturday! oh, and thanks for saying that my diamonds are lovely.

eta: What is fic? sorry, newbie here.

 

[strmrdr]

Date: 2/23/2008 7:09:04 PM
Author: coatimundi


It''s cloudy now so I''m going to go out back and take a few shots in this lighting condition, and then I''ll do some indoor lighting shots. If the sun comes out tomorrow, I''ll try for different sun shots. Maybe at the beach. I''ll be posting soon. Yay Saturday! oh, and thanks for saying that my diamonds are lovely.

eta: What is fic? sorry, newbie here.

kewl on the pics :}

fic is a fiery ideal cut, diamonds cut for fire with exellent light return but tuned for fire.
They have high crowns and fairly shallow pavilions with long lgf%.

 

[jen2M]

This has been so interesting! I feel like I am in class! I wish all my classes in college would have been like this- it would have made it much more fun. Thanks so much for all the info!

 

[strmrdr]

Date: 2/23/2008 7:44:13 PM
Author: jen2M
This has been so interesting! I feel like I am in class! I wish all my classes in college would have been like this- it would have made it much more fun. Thanks so much for all the info!

Your welcome!

 

[shel]

The top 6 things effecting diamond performance are:

lighting

lighting

lighting

lighting

lighting

cut

The more I look at RB diamonds, I more I agree with this statement. If lighting is the great equalizer, and if ideal cuts go dark in direct sunlight, I might consider going with a slightly poorer cut and putting the (small) savings into carat size. Maybe GIA was on to something with its observer-based cut grading system.

 

[strmrdr]

Date: 2/23/2008 8:12:29 PM
Author: shel


The more I look at RB diamonds, I more I agree with this statement. If lighting is the great equalizer, and if ideal cuts go dark in direct sunlight, I might consider going with a slightly poorer cut and putting the (small) savings into carat size. Maybe GIA was on to something with its observer-based cut grading system.

The diamond body may look dark but the light show they are putting on is anything but dark.

What kind of lighting is the person thats going too wear the ring in most?

 

[Venice]

Thank you for the informative lesson - I throughly enjoyed it!! Wouldn''t it be fun if strmrdr would teach a class and we all attended with our diamonds in tow?!! I would be in almost heaven!!!!!!! Show & Tell..........

 

[coatimundi_org]

More lighting conditions.
Photo on the left is overcast outdoor lighting. Photo on right is overcast under a tree.

 

[coatimundi_org]

some more.

Photo on left is incandescent in the fridge! (my personal favorite lighting environment)
Photo on right is flourescent overhead lighting.

 

[coatimundi_org]

Left is halogen lamp light. Almost impossible to shoot without capturing fire.
You really see the rb go darker here. That's what I pictured when I read the original post.

Right is a flourescent light box. Uplit. Flourescent lights are always moving--hard to capture!

That's all I have for now.

Hope these add to the discussion!

 

[strmrdr]

Date: 2/23/2008 9:00:56 PM
Author: coatimundi
some more.

Photo on left is incandescent in the fridge! (my personal favorite lighting environment)
Photo on right is flourescent overhead lighting.

2 of the toughest lighting conditions for diamonds too look good in.

 

[strmrdr]

Date: 2/23/2008 9:05:31 PM
Author: coatimundi
Left is halogen lamp light. Almost impossible to shoot without capturing fire.
You really see the rb go darker here. That''s what I pictured when I read the original post.

Right is a flourescent light box. Uplit. Flourescent lights are always moving--hard to capture!

That''s all I have for now.

Hope these add to the discussion!

under the halogen lighting go for capturing as much fire from the round as you can.

 

[strmrdr]

some points where the dynamic range of the camera is hit.

 

[marcy]

Thanks for the great photos and info. That is how I found PS when I saw my new RB ideal cut stone looked dark in sunlight. I was devastated. It''s a good think it showed a lot of fire or I probably would have wanted to return it.

 

[Ellen]

Date: 2/23/2008 9:37:01 PM
Author: strmrdr

Date: 2/23/2008 9:00:56 PM
Author: coatimundi
some more.

Photo on left is incandescent in the fridge! (my personal favorite lighting environment)
Photo on right is flourescent overhead lighting.

2 of the toughest lighting conditions for diamonds too look good in.

strm, you mean you look at diamonds in your fridge too?

You people are weird.

 

[Cleo]

Just wanted to say I am LOVING this thread!

I was going to ask the question myself, about my RB seeming to go dark in bright sunlight. My A-Level Physics told me it was most probably a perceived effect due to the eyes compensating for the bright, firey flashes (after all, the diamond hasn''t physically changed)... but I was going to post for confirmation.

Storm''s knowledge about diamonds and numbers continues to stun me on a daily basis - thankyou

Coatimundi - I am really enjoying drooling over your gorgeous rings... especially that yummy RB! I think this is a lovely excuse for some extra pics to admire.

I would love to see some pics of Ellen''s and Surfgirl''s fabulous rings in this thread too, under different lighting conditions. (Hint, hint!).

x x x

 

[strmrdr]

Date: 2/24/2008 5:15:06 PM
Author: Cleo
Just wanted to say I am LOVING this thread!

I was going to ask the question myself, about my RB seeming to go dark in bright sunlight. My A-Level Physics told me it was most probably a perceived effect due to the eyes compensating for the bright, firey flashes (after all, the diamond hasn''t physically changed)... but I was going to post for confirmation.

Storm''s knowledge about diamonds and numbers continues to stun me on a daily basis - thankyou

Coatimundi - I am really enjoying drooling over your gorgeous rings... especially that yummy RB! I think this is a lovely excuse for some extra pics to admire.

I would love to see some pics of Ellen''s and Surfgirl''s fabulous rings in this thread too, under different lighting conditions. (Hint, hint!).

x x x

The biggest problem is that color has long been the one of the 3c and its the material color.
Asking what color a diamond is, is like asking what color a mirror is.

 

[coatimundi_org]

The biggest problem is that color has long been the one of the 3c and its the material color.

Asking what color a diamond is, is like asking what color a mirror is.

Yes. This is what I keep thinking as I learn about diamonds. Which is why I always scratch my head at the notion of color sensitivity. I mainly see light when I view a diamond and spectral colors, but not color per se, unless it's a colored diamond.

eta: also, when I try to photograph the "K" color in my round, it almost always eludes me.

 

[Cleo]

Storm, that is very deep for this time on a Sunday night (11.30pm here in England)!

You make an excellent point - but the fact remains that despite the reflections and sparkle presented by diamonds (and mirrors!) they do have their own intrinsic colour when you can see beyond those.

Ancient mirrors have been made from highly polished pieces of gold, silver and bronze - and whilst each of those would give reflections, the mirrors would still have different colours of themselves.

Coatimundi - I wish I could only see sparkle and not colour! My sister in law has a 2ct OEC (bought for far too much money, uncerted and it has a chip!!!

) . I see her diamond, and all I see is its yellow tint... almost like the colour of the Sauvignon blanc I''ve just been drinking... and I just think, ewwww.

Having said that, I am often surprised by the colours of some of the PSers diamonds, and how much whiter they seem than their grading would suggest - another reason to get great cuts!

x x x

 

[coatimundi_org]

Date: 2/24/2008 6:39:19 PM
Author: Cleo
Storm, that is very deep for this time on a Sunday night (11.30pm here in England)!


You make an excellent point - but the fact remains that despite the reflections and sparkle presented by diamonds (and mirrors!) they do have their own intrinsic colour when you can see beyond those.


Ancient mirrors have been made from highly polished pieces of gold, silver and bronze - and whilst each of those would give reflections, the mirrors would still have different colours of themselves.


Coatimundi - I wish I could only see sparkle and not colour! My sister in law has a 2ct OEC (bought for far too much money, uncerted and it has a chip!!!

) . I see her diamond, and all I see is its yellow tint... almost like the colour of the Sauvignon blanc I've just been drinking... and I just think, ewwww.


Having said that, I am often surprised by the colours of some of the PSers diamonds, and how much whiter they seem than their grading would suggest - another reason to get great cuts!


x x x

I wonder where your sister's diamond falls on the color scale. I'm talking about D-L(ish) color in rbs. Maybe hers is more saturated than that? And that's why you notice? Do OECs show more color?

I've noticed color in Cape to yellow colored diamonds for sure.

I do have "clarity" issues though, as I have very good close up vision. Inclusions drive me berserk!

eta: and I do definitely see a tint in different cuts for sure. I just have trouble seeing it with rbs. Ovals? Oh yes indeed. I saw a J oval when I was searching that was very saturated. But then, I saw a 3 carat J colored marquise that was so sparkly that I could not identify any color beyond spectral color.

So much variety in how people see things. Interesting eh?

eta again: Oh, and I forgot to say thank you! for your earlier comment. Thank you Cleo!