Do well cut stones go dark?

[jen2M]

I have a friend who has an amazing ACA H&A RB. It is so pretty. I was looking at it the other day and in the direct sun light or light bulb, the stone went pretty dark- the fire was like nothing I had ever seen- but still, the stone was dark. I have seen other not as well cut diamonds that don''t do this (but not too much fire. Is this a "normal" thing? If so, why does this happen?

 

[coatimundi_org]

My stone goes dark in direct sunlight. If you do a search you'll find some threads on this. Pretty common, I think. I'm not sure why well cut stones do this. The fire, though, is awesome!

If you look at the videos on goodoldgold.com, you'll see stones go dark under certain lighting conditions. Fire pops all over the place!

 

[jen2M]

thanks. I will be sure to check that out.

 

[strmrdr]

Doesn''t actually go dark just exceeds the eyes dynamic range for a small object so appears too go dark.
A video camera has a smaller dynamic range than human vision so it makes it look worse.
The older you are the worse it is as the eyes cant adapt as fast as they used too.
The eyes dynamic range is much more on larger objects than small because as the eyes move they adjust for different parts of what your looking at.

 

[strmrdr]

take a look at this image nice white whites and nice dark blacks.

 

[strmrdr]

now look closely at this image like it was a diamond.

 

[strmrdr]

The whites dont look as white do they?
Thats the difference in dynamic range depending on image size focused on.

 

[strmrdr]

that didn''t work very well because my aviator is too distracting.
If ya want too try it then save them too your desktop then open them...

 

[coatimundi_org]

Thanks for that Strmrdr-very interesting!
How does sunlight affect the eye's viewing of white?

eta: I mean direct sunlight as opposed to flourescent, incandescent, and the like.

or, are you solely referring to direct sunlight with that eye test?

 

[strmrdr]

Date: 2/23/2008 3:22:52 AM
Author: coatimundi
Thanks for that Strmdr-very interesting!
How does sunlight affect the eye''s viewing of white?

White would look brighter in bright light, white is also the best reflector of light even better than silver or shiny metal.

The eye adjusts for bright objects which makes less bright objects look dark or even black.
Then look at a bright diamond and it goes further adjusting towards the bright side.., making the diamond body look even darker.


this is one of the reasons I''m extremely skeptical of fire and scintillation studies being done with diamonds.

 

[coatimundi_org]

Date: 2/23/2008 3:29:18 AM
Author: strmrdr

Date: 2/23/2008 3:22:52 AM

Author: coatimundi

Thanks for that Strmdr-very interesting!

How does sunlight affect the eye's viewing of white?

White would look brighter in bright light, white is also the best reflector of light even better than silver or shiny metal.


The eye adjusts for bright objects which makes less bright objects look dark or even black.

Then look at a bright diamond and it goes further adjusting towards the bright side.., making the diamond body look even darker.



this is one of the reasons I'm extremely skeptical of fire and scintillation studies being done with diamonds.

so, as the eye adjusts, the body of the diamond darkens-balancing the light that is returned to the eye?

Would you say that it's hard to measure fire and scintillation, because the eye is constantly adjusting, and people's eyes do this at different rates, so to speak?

 

[strmrdr]

Date: 2/23/2008 3:42:42 AM
Author: coatimundi


so, as the eye adjusts, the body of the diamond darkens-balancing the light that is returned to the eye?

Would you say that it's hard to measure the perception of fire and scintillation, because the eye is constantly adjusting, and people's eyes do this at different rates, so to speak?

it looks darker because the eye adjusted for the bright light of the light beams striking the eye.

YES!!! to the second part! Throw glasses into the mix and its even more complicated!

Another thing is eyes are drawn too bright objects, try this while sitting looking at the computer have someone turn a small flashlight on and off but pointing away from you.
After a very short time it will drive you bonkers as you eyes are drawn away from the monitor.
I used too have fun with a laser pointer doing this at work.
Why does the brain/eyes work this way?
Easy, often the first visual hint of an animal attack at night will be the flash of light off the animals eyes! Small bright flash, brain goes woops that needs attention NOW!
Getting attention drawn to bright objects saved lives!
It has been proven that human reaction time to flashing light is far faster than that of sound when used for warning devices.
Why? A threat was generally heard at greater distance but if it was the eye reflection that triggered a warning there was only seconds or less too respond.

 

[coatimundi_org]

Date: 2/23/2008 4:01:25 AM
Author: strmrdr

Date: 2/23/2008 3:42:42 AM

Author: coatimundi



so, as the eye adjusts, the body of the diamond darkens-balancing the light that is returned to the eye?


Would you say that it's hard to measure the perception of fire and scintillation, because the eye is constantly adjusting, and people's eyes do this at different rates, so to speak?

it looks darker because the eye adjusted for the bright light of the light beams striking the eye.


YES!!! to the second part! Throw glasses into the mix and its even more complicated!


Another thing is eyes are drawn too bright objects, try this while sitting looking at the computer have someone turn a small flashlight on and off but pointing away from you.

After a very short time it will drive you bonkers as you eyes are drawn away from the monitor.

I used too have fun with a laser pointer doing this at work.

Why does the brain/eyes work this way?

Easy, often the first visual hint of an animal attack at night will be the flash of light off the animals eyes! Small bright flash, brain goes woops that needs attention NOW!

Getting attention drawn to bright objects saved lives!

It has been proven that human reaction time to flashing light is far faster than that of sound when used for warning devices.

Why? A threat was generally heard at greater distance but if it was the eye reflection that triggered a warning there was only seconds or less too respond.

In high school, I did a light vs. sound reaction time experiment for the science fair. 2nd place, by the way. I measured reaction times for hitting the brakes while driving, using sound (honking) vs. light (break lights). The lights had faster reaction times by far. Not groundbreaking or anything, but hey! it was high school.

Sometimes my diamond is so bright it literally hurts my eyes. I think I can actually feel the pupil retracting. This happens when I flash my flashlight at the diamond. Incredibly bright.

 

[strmrdr]

Date: 2/23/2008 4:13:33 AM
Author: coatimundi


In high school, I did a light vs. sound reaction time experiment for the science fair. 2nd place, by the way. I measured reaction times for hitting the brakes while driving, using sound (honking) vs. light (break lights). The lights had faster reaction times by far. Not groundbreaking or anything, but hey! it was high school.

Sometimes my diamond is so bright it literally hurts my eyes. I think I can actually feel the pupil retracting. This happens when I flash my flashlight at the diamond. Incredibly bright.

kewl on the science fair.
I had a lot of fun doing them in grade school. Made all state once but parents car broke down and didn''t get too go.
I built a electrical generator and power grid from scratch.
Went too all city 3 times in 4th 5th and 6th grade. Got a 2nd, first but lost in the all state invite competition(top 4 went mine was 6th out of 20), and a first then won an all state invite but didn''t make it too the state event.
Did do them in middle school or high school.

if it hurts don''t do it because you can damage your eye that way. :}

 

[coatimundi_org]

Whoa-you built a generator and power grid from scratch? That's awesome, man.

I did Odyssey of the Mind for awhile. Our team won 3rd place at state, 1st place at regionals(freshman year of high school), with a balsa wood structure that held quite a bit of weight. Balsa wood is a wily material-I like to think of it as an unsung hero.

No more flashlight on the diamond for me!

eta: sorry about the car breakdown. That sucks.

 

[just looking]

The eye adjusts for bright objects which makes less bright objects look dark or even black.
Then look at a bright diamond and it goes further adjusting towards the bright side.., making the diamond body look even darker.

this is one of the reasons I''m extremely skeptical of fire and scintillation studies being done with diamond


Srmrdr,

Just happened to be reviewing some threads and noticed your comment. I was watching a video on this just the other night. Actually it was a video of a dealer then I found another video of another dealer. This dealer stated he was skeptical as well and suggested that if you take lesser quality diamonds and put them under the same conditions they will look very good. Do think it goes to that extent, if you take a "good" rated vs say an IDeal cut, would they come close?

Regards,
Matt

 

[strmrdr]

Date: 2/23/2008 7:49:25 AM
Author: just looking

The eye adjusts for bright objects which makes less bright objects look dark or even black.
Then look at a bright diamond and it goes further adjusting towards the bright side.., making the diamond body look even darker.


this is one of the reasons I''m extremely skeptical of fire and scintillation studies being done with diamond


Srmrdr,

Just happened to be reviewing some threads and noticed your comment. I was watching a video on this just the other night. Actually it was a video of a dealer then I found another video of another dealer. This dealer stated he was skeptical as well and suggested that if you take lesser quality diamonds and put them under the same conditions they will look very good. Do think it goes to that extent, if you take a ''good'' rated vs say an IDeal cut, would they come close?

Regards,
Matt

bright lighting can make almost any diamond look good which is why jewelery stores use bright spot lights set too shine over your shoulder.
Where the real difference between well cut and not so well cut stones come into play is diffused lighting and soft lighting.
The top 6 things effecting diamond performance are:
lighting
lighting
lighting
lighting
lighting
cut

 

[Ellen]

strm, wouldn''t cut be at the top? Cuz without a great cut, all those lighting situations wouldn''t have as great an impact on performance, right?

Or am I missing something, which is entirely possible.

 

[strmrdr]

Date: 2/23/2008 1:27:11 PM
Author: Ellen
strm, wouldn''t cut be at the top? Cuz without a great cut, all those lighting situations wouldn''t have as great an impact on performance, right?

Or am I missing something, which is entirely possible.

nope because in some lighting judging diamond quality is impossible.
You might be able too pick out a nail head but pretty much any other might look good in bright spot lighting.

 

[strmrdr]

further the lighting determines what type of light is returned, white light or colored light with the cut determining the boundaries between where it switches over.
The difference between a tic and a fic is the percentage of lighting types it will show fire vs white light, not that it has better fire in the top fire producing lighting.

 

[Ellen]

Ok, I think I see what you''re saying.

 

[ksinger]

I just thought that''s what diamonds DO.....I guess....
My stone appears to go dark in direct sunlight, and in the bathrooms where I work.

(We have recently remodeled bathrooms and the lighting is quite lovely....the automatic toilets are another thing entirely....) And scintillation and fire just blaze out of it. Makes one of the most basic and pedestrian human functions, a LOT more diverting I can tell you!

Standing under those wonderful lights while washing my hands is great!

You know, I love that look of the stone under that hugely bright, focused light, the best of all the lighting conditions. It''s so sultry somehow. It may explain why I like brown and other colored diamonds so well....

 

[coatimundi_org]

bright lighting can make almost any diamond look good which is why jewelery stores use bright spot lights set too shine over your shoulder.

Where the real difference between well cut and not so well cut stones come into play is diffused lighting and soft lighting.

The top 6 things effecting diamond performance are:

lighting

lighting

lighting

lighting

lighting

cut

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

 

[strmrdr]

here is another part of the puzzle..
Which is the darker black?

 

[whatmeworry]

Date: 2/23/2008 7:49:25 AM
Author: just looking
The eye adjusts for bright objects which makes less bright objects look dark or even black.

Then look at a bright diamond and it goes further adjusting towards the bright side.., making the diamond body look even darker.



this is one of the reasons I''m extremely skeptical of fire and scintillation studies being done with diamond



Srmrdr,


Just happened to be reviewing some threads and noticed your comment. I was watching a video on this just the other night. Actually it was a video of a dealer then I found another video of another dealer. This dealer stated he was skeptical as well and suggested that if you take lesser quality diamonds and put them under the same conditions they will look very good. Do think it goes to that extent, if you take a ''good'' rated vs say an IDeal cut, would they come close?


Regards,

Matt

In some lighting conditions a ''good'' would look better than an ''ideal''. Check out this
http://https://www.pricescope.com/community/threads/fancy-light-yellow-fancy-or-cape.66898/. About 2/3 of the way down Garry H has a great graphic showing lots of cuts in different lighting situations.

 

[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.

 

[strmrdr]

Date: 2/23/2008 2:44:23 PM
Author: whatmeworry


In some lighting conditions a ''good'' would look better than an ''ideal''. Check out this
http://https://www.pricescope.com/community/threads/fancy-light-yellow-fancy-or-cape.66898/. About 2/3 of the way down Garry H has a great graphic showing lots of cuts in different lighting situations.

While that is true, Garry is getting into his anti-GIA crusade there so be careful how much weight you put on it.
The thing too be careful of is the camera can lie too you because it don''t always show what your eye will see.
The dynamic range is totally different.
Pictures of diamonds in bright direct lighting will be different than what your eye will see.
At best they can give a general idea.

 

[coatimundi_org]

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.

Here are my results.
Left is direct sunlight. Right is under a tree. Both diamonds went berserk under the tree. 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. Hard to assess from these photos, though. I'll try to capture this beserkedness more at some other point.

Thanks for the help Strmrdr!

eta: oh, and the kite side stones went berserk too. In a large chunky faceted way.

 

[strmrdr]

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


Here are my results.
Left is direct sunlight. Right is under a tree. Both diamonds went berserk under the tree. The oval showed more fire and brilliance where the facets are the largest in the center and sides of the stone. The round seemed uniform. Hard to assess from these photos, though. I''ll try to capture this beserkedness more at some other point.

Thanks for the help Strmrdr!

eta: oh, and the kite side stones went berserk too. In a large chunky faceted way.

kicken thank you for doing this!
I have too head out for a couple hours but when I get back I think using your experience and images I can pull this all together in an understandable way :}

 

[coatimundi_org]

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.