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darkness in ideal cut diamonds, revisited

slg47

Ideal_Rock
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Apr 4, 2010
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9,667
diamonds usually appear quite dark when seen in direct sunlight
from knowledge page

https://www.pricescope.com/community/threads/darknesss-in-ideal-cut-diamonds.145684/#post-2629075#p2629075/

I have noticed that my diamond appears quite dark in direct sunlight, and I am curious as to why? I found this thread but would like a more detailed explanation than
that the stones are returning so much light the human eye compensates and makes them darker.
if anyone has one?

thanks
 

John P

Ideal_Rock
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3,563
Thanks for linking that thread SC.

Along with the linked info it's also worth remembering that the sun sub-tends light at about one-half a degree. This means that, in the entire 180-degree hemisphere, the sun is one tiny point light source occupying only 1/360 of the total area a diamond "looks" for light... So while you see the (very) bright sparkles that this single point source creates, the accommodation by our eyes (per the linked thread) makes the surrounding areas effectively dark.

If you walked into a jewelry store and killed all of the lights in the ceiling except for one you'd get the same result, only the diamond would be even more dark since no jeweler's spotlight can rival our sun in intensity or ambiance...so powerful it makes Superman strong. Conversely, if we had 20 suns in the sky it would be like standing in the most amazing jeweler's showroom ever - but we probably wouldn't notice how groovy our diamond looked because we'd be hopping on the melted-slag of the sidewalks. :shock:

A good reminder for diamond-lovers when the sun comes out to play: One of the best viewing conditions for diamonds is under a leafy tree on a sunny day. The leaves above break the sun's single half-degree point source into many point sources, causing terrific brilliance as well as fire. Be careful though - you can stand there hypnotized by your finger-blinger for hours.
 

ChunkyCushionLover

Ideal_Rock
Joined
Jun 21, 2009
Messages
2,463
John Pollard said:
Thanks for linking that thread SC.

Along with the linked info it's also worth remembering that the sun sub-tends light at about one-half a degree. This means that, in the entire 180-degree hemisphere, the sun is one tiny point light source occupying only 1/360 of the total area a diamond "looks" for light... So while you see the (very) bright sparkles that this single point source creates, the accommodation by our eyes (per the linked thread) makes the surrounding areas effectively dark.

If you walked into a jewelry store and killed all of the lights in the ceiling except for one you'd get the same result, only the diamond would be even more dark since no jeweler's spotlight can rival our sun in intensity or ambiance...so powerful it makes Superman strong. Conversely, if we had 20 suns in the sky it would be like standing in the most amazing jeweler's showroom ever - but we probably wouldn't notice how groovy our diamond looked because we'd be hopping on the melted-slag of the sidewalks. :shock:

A good reminder for diamond-lovers when the sun comes out to play: One of the best viewing conditions for diamonds is under a leafy tree on a sunny day. The leaves above break the sun's single half-degree point source into many point sources, causing terrific brilliance as well as fire. Be careful though - you can stand there hypnotized by your finger-blinger for hours.

Great explanation Johhhhhhhhhhhhhhhhhhhhhhhhn. I gave you back extra Hs just in case I missed some in addressing you in some past posts.
 

Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,323
It'd be neat if we could observe ideal cut rocks in a place like Orion's belt (at the Orion nebula) where a planet would have 4 suns. :sun: slg, I have this phenomena captured in a few clips as well where we discuss it as it is observed in spot lighting too which might help.
 

John P

Ideal_Rock
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Messages
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ChunkyCushionLover said:
Great explanation Johhhhhhhhhhhhhhhhhhhhhhhhn. I gave you back extra Hs just in case I missed some in addressing you in some past posts.

Appreciate it :) I'll keep some around for when others do it. 'appens 'ere and t'ere.
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
31,318
Your pupils get smaller in response to the VERY bright highlights a diamond gives off in sunlight.
That makes the rest of the diamond seem dark.
Poorly cut diamonds may return fewer highlights so your pupils do not constrict as much, making them not seem as dark in sunlight as well-cut diamonds.

Don't blame the diamond; blame nature, evolution or God, whatever your thing is.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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Aug 15, 2000
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17,428
John Pollard said:
Thanks for linking that thread SC.

Along with the linked info it's also worth remembering that the sun sub-tends light at about one-half a degree. This means that, in the entire 180-degree hemisphere, the sun is one tiny point light source occupying only 1/360 of the total area a diamond "looks" for light... So while you see the (very) bright sparkles that this single point source creates, the accommodation by our eyes (per the linked thread) makes the surrounding areas effectively dark.

If you walked into a jewelry store and killed all of the lights in the ceiling except for one you'd get the same result, only the diamond would be even more dark since no jeweler's spotlight can rival our sun in intensity or ambiance...so powerful it makes Superman strong. Conversely, if we had 20 suns in the sky it would be like standing in the most amazing jeweler's showroom ever - but we probably wouldn't notice how groovy our diamond looked because we'd be hopping on the melted-slag of the sidewalks. :shock:

A good reminder for diamond-lovers when the sun comes out to play: One of the best viewing conditions for diamonds is under a leafy tree on a sunny day. The leaves above break the sun's single half-degree point source into many point sources, causing terrific brilliance as well as fire. Be careful though - you can stand there hypnotized by your finger-blinger for hours.

John's explanation is great - especially too - that bold line, and another part - our eye accomodates not just for the brightness of the diamond, but all the background as well.
We never notice it because we are totally conditioned after a few days of birth.
But we see it all the time in photo's - an auto camera does the same sort of thing as our eye's, but without the clever adaption ability.
Unfortunately it is overcast, but I just took these pic's standing at my window with the clouded sun facing the stones, 1. good and bad CZ on white paper, 2, on black paper, and at my desk with the window to my right and a single overhead 35W fluro.

Human eye adaption.jpg
 

mrsfivefiveten

Rough_Rock
Joined
Mar 10, 2010
Messages
16
Garry H (Cut Nut) said:
John Pollard said:
Thanks for linking that thread SC.

Along with the linked info it's also worth remembering that the sun sub-tends light at about one-half a degree. This means that, in the entire 180-degree hemisphere, the sun is one tiny point light source occupying only 1/360 of the total area a diamond "looks" for light... So while you see the (very) bright sparkles that this single point source creates, the accommodation by our eyes (per the linked thread) makes the surrounding areas effectively dark.

If you walked into a jewelry store and killed all of the lights in the ceiling except for one you'd get the same result, only the diamond would be even more dark since no jeweler's spotlight can rival our sun in intensity or ambiance...so powerful it makes Superman strong. Conversely, if we had 20 suns in the sky it would be like standing in the most amazing jeweler's showroom ever - but we probably wouldn't notice how groovy our diamond looked because we'd be hopping on the melted-slag of the sidewalks. :shock:

A good reminder for diamond-lovers when the sun comes out to play: One of the best viewing conditions for diamonds is under a leafy tree on a sunny day. The leaves above break the sun's single half-degree point source into many point sources, causing terrific brilliance as well as fire. Be careful though - you can stand there hypnotized by your finger-blinger for hours.

John's explanation is great - especially too - that bold line, and another part - our eye accomodates not just for the brightness of the diamond, but all the background as well.
We never notice it because we are totally conditioned after a few days of birth.
But we see it all the time in photo's - an auto camera does the same sort of thing as our eye's, but without the clever adaption ability.
Unfortunately it is overcast, but I just took these pic's standing at my window with the clouded sun facing the stones, 1. good and bad CZ on white paper, 2, on black paper, and at my desk with the window to my right and a single overhead 35W fluro.

Thanks for the photos Garry! I was having trouble visualizing this effect... Very interesting. It also explains why my square cut emerald shows better (more sparkly) in indirect lighting...
 

yssie

Super_Ideal_Rock
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Aug 14, 2009
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Great discussion and thanks for the pics Garry!
 

slg47

Ideal_Rock
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Apr 4, 2010
Messages
9,667
just wanted to add that my center stone goes dark in the sunlight but the side stones are quite bright...it is really interesting to see!
 
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