Light return in fancy colored diamonds, what do you see?

[natascha]

Hi everyone,

I asked about this first in rocky talky before it occurred to me that many FCD owners hang out here and maybe don't frequent RT so much.

My question to you all is what color light return do you see from your FCD? The type where white diamonds scintillate and throw out white light, what does your FCD do?

The reason why I am asking is that I love stones with a brown tint, however I strongly dislike yellow. I bought a pair of champagne studs (mainly brown with a tad of yellow) and while I love the body color I hate the light return, it is really yellow/golden.

I tried to show this in the photo, where the brown studs are compared with my white ones (OEC H/I color).

I am hoping that if a stone is a true brown it won't give out yellow light but a creamy beige, am I fooling myself?

The stone I might be interested in is this one, really awful photo so I am going to go take a look at it in person since you can't really tell anything from the pic. Any comments on the stone are welcome .

 

[kenny]

If you are talking about soft even lighting from a large source such as a very cloudy day that will not result in a rainbow of colors coming even from a white diamond I'll see many different intensities of green in my green diamond, many different intensities of blue in my blue diamond, etc. (Ignoring the reflections of my colored shirt or nearby objects).

But if you are talking about a diamond dispersing light into the colors of the rainbow from a small source like the sun or a halogen light then . . . I think I can get all colors of the rainbow out of each diamond, but I feel they are all tinted somewhat in the direction of the body color of the FCD.
Whether that tint is perceptible by the human eye would be tough to measure/prove and would certainly be most noticeable on the most strongly colored FCDs.

I used to have the misconception that a green diamond would only give off green light even when lit by a spotlight.
Not true.
When the lighting conditions are right FCDs still break up light into the rainbow.

I have FCDs of several colors.
Tomorrow if the sun comes out maybe I'll do some experimenting and report more, and maybe try to get some pics of green coming from a red diamond, red from a green diamond, blue from an orange one and orange from a blue one... those all being opposites in color.
An FCD will absorb more of its opposite than it will other colors, for example a green diamond will attenuate the red more than any other color and green the least.

The more saturated the diamond and the darker the tone the more the light is absorbed and tinted.

 

[davi_el_mejor]

I notice white light return, body color return and full fire in my FCD's.


Fancy Light yellow Orange (on top)
Fancy Deep Yellow Brown (bottom)
Body color return


Fancy Deep Yellow Brown
white light returm


Fancy brownish orangy Yellow
mix of both

I don't have any pictures of the fire thrown off, but believe me, it's there!

Now onto the prospective stone. It looks like a fancy deep brown with very little modifiers in the picture. However, in proper lighting, I think there will be grey in it. This will make it a cooler brown as opposed a warm brown (like the singular ring pictured). I think it's definitely worth seeing IMO. It looks like an old cut stone and to me that's a bonus

 

[kenny]

This is a color wheel.
It is useful for understanding opposite or complimentary colors.

An opposite color is simply the color on the opposite side of the wheel.
Red's opposite the green.
Blue's opposite the orange.
Yellow's opposite is purple.

I bring this up because it is related to the OP's very good question, "What light return do you see in FCDs?"

Under spotlighting FCDs offer all the colors of the rainbow just like a white diamond.
BUT they also do two things...

They attenuate all colors some since they are not perfectly clear; the darkest diamond attenuate light the most.
They do not attenuate all colors equally.
They will attenuate their opposite the most and offer relatively little attenuation to their own body color.
That means a blue diamond will give off fire of all colors of the rainbow but the closer a fire flash is to orange the more it will be attenuated.
That doesn't mean there are no orange flashes; orange flashes will just be fainter in a blue diamond.
The effect will be more pronounced in a dark blue diamond than a faint blue one.

 

[kenny]

I just spend about four hours fighting to get an image this good, though I know I can do better.
This is my Fancy Intense Green diamond in full sunlight.
It was resting on a white plate which I moved around to find the strongest red fire, also adjusting the height of the camera on the tripod.
To expose for the red fire I had to adjust the camera for that intense brightness, which of course darkens the green diamond down into the mud.
I'm already thinking of concocting an artificial light set up to get such red fire from a less-bright pointed light source so I can also capture the diamond's pretty green color.

At least this is proof that a colored diamond can produce dispersion colors that are the opposite of their body color.

I also took some shots of my Red diamond trying to capture the green I saw, the Blue diamond trying to capture orange, and the Yellowish Orange diamond trying to capture greenish blue.
The images I've gotten so far are not as striking as the one below but I'll try to get some up too.

I will comment that the FCDs DO favor dispersion fire color matching their body color and are much more stingy giving off color that is the opposite of their body color.

This has also been another huge learning experience photographing FCDs.
As you know you can move the diamond slightly and watch the colors move through the rainbow.
I did that looking into my DSLR and stopping when I had the desired color and took the pic.
To my suprise most pics were shifted away from the red area so I had to compensate by moving the diamond beyond the color I wanted.
Also much experimentation was needed since the camera's sensor is so easily blinded causing the color I see with my eyes in the viewfinder to just wash out to white.

 

[T L]

I will comment that the FCDs DO favor dispersion fire color matching their body color and are much more stingy giving off color that is the opposite of their body color.

My greyish green diamond gives off lots of red, orange and blue, so in my own particular case (of a single stone) that doesn't correlate with the bolded sentence above. I guess there are some exceptions. This photo shows some of the dispersion, which is more dramatic IRL. My camera isn't the best at capturing dispersion.

 

[davi_el_mejor]

This is the light yellow orange loose

Best I could find from what I've uploaded to PS already



In this one the fire is faint, but I was able to capture the whole spectrum

 

[kenny]

Here's green dispersion coming from a Red diamond.

This is also a great example of what happens when a camera's sensor (Nikon D7000) gets overloaded with bright light.
I can argue that the green flare emanating from both sides of the highlight is proof that the color between them was also green, but it was so bright that it blinded the sensor.
I assure you what I saw in the viewfinder was pure bright green.

The human eye has a much wider latitude than a film or a digital camera.
IOW the human eye/brain system can make out/resolve/see/get detail from much brighter and darker stuff than any camera.
Once again the solution is to set up a pointed electric light that is not as bright as the sun.

 

[kenny]

I will comment that the FCDs DO favor dispersion fire color matching their body color and are much more stingy giving off color that is the opposite of their body color.

My greyish green diamond gives off lots of red, orange and blue, so in my own particular case (of a single stone) that doesn't correlate with the bolded sentence above. I guess there are some exceptions. This photo shows some of the dispersion, which is more dramatic IRL. My camera isn't the best at capturing dispersion.

I cannot argue with "lots of".
But the laws of physics and optics dictate that the color in your diamond does attenuate (not eliminate) all colors and offers the greatest attenuation to the opposite color of its main body color of green, which is red.

Just because you see "plenty" of red does not mean that the amount of red you see wasn't attenuated some by the green in your diamond.
Even after dispersed fire from sunlight is attenuated a great deal it is still VERY bright
My red diamond is very saturated so it attenuates light a great deal yet in sunlight enough of all the colors of the rainbow get through.

With all due respect TL (and I do respect you a great deal) this is not religion where we all can believe whatever exceptions we want and everyone just respects it to be polite.
This is science.

LOVELY diamond BTW!

 

[kenny]

Here's some orange dispersion from a Fancy Intense Blue diamond, once again opposites sides of the color wheel.
(For the record this blue was graded Fancy Intense blue but this is a soft blue diamond, GIA is pretty generous when grading Blues.)

 

[T L]

I will comment that the FCDs DO favor dispersion fire color matching their body color and are much more stingy giving off color that is the opposite of their body color.

My greyish green diamond gives off lots of red, orange and blue, so in my own particular case (of a single stone) that doesn't correlate with the bolded sentence above. I guess there are some exceptions. This photo shows some of the dispersion, which is more dramatic IRL. My camera isn't the best at capturing dispersion.

I cannot argue with "lots of".
But the laws of physics and optics dictate that the color in your diamond does attenuate (not eliminate) all colors and offers the greatest attenuation to the opposite color of its main body color of green, which is red.

Just because you see "plenty" of red does not mean that the amount of red you see wasn't attenuated some by the green in your diamond.
Even after dispersed fire from sunlight is attenuated a great deal it is still VERY bright
My red diamond is very saturated so it attenuates light a great deal yet in sunlight enough of all the colors of the rainbow get through.

With all due respect TL (and I do respect you a great deal) this is not religion where we all can believe whatever exceptions we want and everyone just respects it to be polite.
This is science.

LOVELY diamond BTW!

Kenny, sorry, but I'm confused at the above bolded statement. I have great respect for the laws of science and as for the example I posted above, it was just one example that may not follow the norm, which is why I posted it. I enjoy the discourse, and like to hear a difference of opinion, but one cannot argue with physics, which I am always seeking to learn more from.

 

[kenny]

Kenny, sorry, but I'm confused at the above bolded statement. I have great respect for the laws of science and as for the example I posted above, it was just one example that may not follow the norm, which is why I posted it. I enjoy the discourse, and like to hear a difference of opinion, but one cannot argue with physics, which I am always seeking to learn more from.

What I was replying to was you felt your diamond may be an exception to what I was referring to - which is based on the rules of physics.

Again sunlight is sooooo bright that even when colors are attenuated they still look blindingly bright to our eyes.
Imagine we had a white D-colored diamond cut identically to your green.
Then we placed them side by side and use a scientific instrument to measure the strength of each color of light coming from both diamonds.
The instrument will without question detect that your green diamond has attenuated all colors of the dispersion fire especially those closest to red, (the opposite color of your green diamond).
Now, whether the human eye is sensitive enough to detect the difference between what are both incredibly bright things is certainly debatable.

So, it is not that your diamond is an exception.
Rather IMHO a more reasonable explanation is that your eye/brain system, and mine, is not terribly precise at detecting differences in two VERY bright things.
It's kind of like the difference between being hit by a car going 90 MPH and a mile-long freight train going 90 MPH.
There absolutely IS a difference in the energy your body will absorb, a huge one, but it may mean little in terms of your experience.

 

[T L]

Kenny, sorry, but I'm confused at the above bolded statement. I have great respect for the laws of science and as for the example I posted above, it was just one example that may not follow the norm, which is why I posted it. I enjoy the discourse, and like to hear a difference of opinion, but one cannot argue with physics, which I am always seeking to learn more from.

What I was replying to was you felt your diamond may be an exception to what I was referring to - which is based on the rules of physics.

Again sunlight is sooooo bright that even when colors are attenuated they still look blindingly bright to our eyes.
Imagine we had a white D-colored diamond cut identically to your green.
Then we placed them side by side and use a scientific instrument to measure the strength of each color of light coming from both diamonds.
The instrument will without question detect that your green diamond has attenuated all colors of the dispersion fire especially those closest to red, (the opposite color of your green diamond).
Now, whether the human eye is sensitive enough to detect the difference between what are both incredibly bright things is certainly debatable.

So, it is not that your diamond is an exception.
Rather IMHO a more reasonable explanation is that your eye/brain system, and mine, is not terribly precise at detecting differences in two VERY bright things.
It's kind of like the difference between being hit by a car going 90 MPH and a mile-long freight train going 90 MPH.
There absolutely IS a difference in the energy your body will absorb, a huge one, but it may mean little in terms of your experience.

Kenny,
Thank you for clarifying.

I see dispersion like that in artificial light as well, which isn't nearly as bright as sunlight. The lighting doesn't even have to be very bright, (think of jeweler's lighting). Therefore, I think it also depends on the type of lighting as well. There are some other factors to consider. I have heard that dark greenish grey diamonds do have a great deal of dispersion of various colors, so my experience isn't unique. I also wonder if fluorescence has some bearing on the dispersion of color in an FCD as well.

 

[natascha]

Thank you all for the wonderful photos and responses, very interesting discussion.

Davi- I have to say that I love the designs of your rings, they complement the stones so well. Is your Fancy deep yellow brown set in rose gold? If so how would you say it has affected the color and performance of your stone? In your photo it shows a lot of white light, does it also show light the same color as it's body color or does it lean more towards yellow colored light return?

Regarding the stone I am considering, yes I also believe it is an old cut, I am an old cut nut so that is practically a must in my opinion. I agree that it, from the really bad evidence I have, it seems like a brown with some grey. It will be very interesting to see how intense the color is.

I am wondering if the darkness in the middle might be due to a bad cut or maybe the photo? Since only the center seems that dark.

Kenny- As always your photography skills are absolutely amazing. Your minty green still gives me goosebumps every time I see it.

Do you mean that the body color will affect the perception of the color of fire or do you mean it will actually affect the colors produced?

How do you think a brown stone will affect both white light return and fire? Brown does not really have a complementary color or?

TL- Where white diamond throw out white light, what color does your lovely grayish green diamond give?

What is the word for white light return (that is not always white )? Scintillation? But isn't that the light play of the facets that turn on and off?

I am wondering about what you can see in the photo below. The white diamond shows trows out white light, but the champagne diamonds throw out golden-yellow light.

 

[kenny]

Kenny,
Thank you for clarifying.

I see dispersion like that in artificial light as well, which isn't nearly as bright as sunlight. The lighting doesn't even have to be very bright, (think of jeweler's lighting). Therefore, I think it also depends on the type of lighting as well. There are some other factors to consider. I have heard that dark greenish grey diamonds do have a great deal of dispersion of various colors, so my experience isn't unique. I also wonder if fluorescence has some bearing on the dispersion of color in an FCD as well.

All excellent points, TL.
One thing I really love about FCDs is there always seems to be something new to learn about them and photography.

I concur about not needing sunlight to get dispersion.
I once smuggled my FCD case into Costco. OMG!

Interesting about the greyish green.
One factor may be that your diamond is not very dark; darkness in diamonds attenuates light.
Also the gray attenuates all colors equally since gray is not a color, perhaps that is a factor in making grayish green seem to be more dispersive, or less-selectively-dispersive rather.

Also I wanted to state that even though my pics of the red and the green diamond prove an FCD with a strong pure color can produce dispersive fire of the opposite color my experience in real life and in the project to find and photograph that opposite color has taught me that those opposite colors are harder to get, and they are not as strong as the dispersed colors which are closer to the body color of an FCD.

 

[T L]

TL- Where white diamond throw out white light, what color does your lovely grayish green diamond give?

If you're talking about body color or dispersion, that's two different things. The body color is grayish green, and the dispersion is red, orange, yellow, blue. White diamonds aren't really "white" - that's a term for a colorless diamond. They break up white light and throw off all the colors of the rainbow as a clear prism would. There are actually "fancy white" diamonds which do have a cloudy white color, but they're not the same as diamonds in the DEFG color range. Hope that makes sense.

 

[T L]

Interesting about the greyish green.
One factor may be that your diamond is not very dark; darkness in diamonds attenuates light.
Also the gray attenuates all colors equally since gray is not a color, perhaps that is a factor in making grayish green seem to be more dispersive, or less-selectively-dispersive rather.

Yes, that may be the reason I think. I wonder how pure grey diamonds disperse light.

 

[kenny]

Do you mean that the body color will affect the perception of the color of fire or do you mean it will actually affect the colors produced?

That's an intricate and nuanced question.
If a tree falls in a forrest but nobody hears it does it make a sound?

The green body color has to affect the red we see, because it was not a white diamond; it was a green filter.
It will affect it not in a mixing way but in a darkening way since red and green are opposites.

The green diamond attenuates the red light to some degree.
(Again, attenuate means to lower the strength.)
But the red dispersion from the sunlight was so strong that even after being attenuated a little by the green body material of the diamond there was PLENTY of strength of red light left over for us to view as what looks like pure red.
If the diamond was white it would also look like pure red, just a bit brighter.

Let me put it this way.
As the pic above shows, red light can come from a green diamond.
Actually the photograph does not really do it justice because the red I saw with my eyes was a more pure fire engine red, while the red in the pic leans towards orange.

I suspect that is a side effect of the camera's sensor when presented with such blindly bright red sunlight.

 

[kenny]

Interesting about the greyish green.
One factor may be that your diamond is not very dark; darkness in diamonds attenuates light.
Also the gray attenuates all colors equally since gray is not a color, perhaps that is a factor in making grayish green seem to be more dispersive, or less-selectively-dispersive rather.

Yes, that may be the reason I think. I wonder how pure grey diamonds disperse light.

The same way every diamond disperses light.
It just disperses it.

Gray will attenuate all colors equally.

 

[kenny]

How do you think a brown stone will affect both white light return and fire?
Brown does not really have a complementary color or?

By white light return I assume you are referring to what we will see when the brown diamond is lit by soft even light of a large source like a very white-cloudy day.

In that lighting a brown stone will show various strengths of its own body color of brown.

In spot lighting it will disperse light into all of the colors of the rainbow but will attenuate them somewhat through a brown filter.
If the light is strong enough, like full sun, and the brown diamond is not too dark I suspect you'll see the colors of the rainbow (not noticeably brownish) but I'd love to hear your feedback about this since I have not bought a brown diamond yet and I may be way off base here.
A brown may be my next newborn.

Yes, brown is not on the color wheel.
IIRC, brown is made by mixing more than two colors so we can't really pinpoint a color that will be attenuated more than other colors though it seems reasonable to me brown is on the warm side so the cooler colors (closest to blue) will be more attenuated than the warmer colors like orange.

 

[natascha]

TL- Where white diamond throw out white light, what color does your lovely grayish green diamond give?

If you're talking about body color or dispersion, that's two different things. The body color is grayish green, and the dispersion is red, orange, yellow, blue. White diamonds aren't really "white" - that's a term for a colorless diamond. They break up white light and throw off all the colors of the rainbow as a clear prism would. There are actually "fancy white" diamonds which do have a cloudy white color, but they're not the same as diamonds in the DEFG color range. Hope that makes sense.

I seem to have trouble explaining my thoughts today . I understand the difference of body color and scintillation. When I say white diamonds I mean diamonds that fall into the colorless and near colorless range. I always thought people just said white diamonds since otherwise it becomes a mouthful, not that they actually believed diamonds are white.

If you look at the photo I posted the H/I diamond shows bright light that I perceive as white light meanwhile the champagne colored diamond shows bright yellowish/golden light however it's body color is mainly brown. I would have expected a light brown or beige colored light, not yellow. Therefore I wondered what color you see your diamonds return (in dispersed lighting situations).

 

[natascha]

Do you mean that the body color will affect the perception of the color of fire or do you mean it will actually affect the colors produced?

That's an intricate and nuanced question.
If a tree falls in a forrest but nobody hears it does it make a sound?

The green body color has to affect the red we see, because it was not a white diamond; it was a green filter.
It will affect it not in a mixing way but in a darkening way since red and green are opposites.

The green diamond attenuates the red light to some degree.
(Again, attenuate means to lower the strength.)
But the red dispersion from the sunlight was so strong that even after being attenuated a little by the green body material of the diamond there was PLENTY of strength of red light left over for us to view as what looks like pure red.
If the diamond was white it would also look like pure red, just a bit brighter.

Let me put it this way.
As the pic above shows, red light can come from a green diamond.
Actually the photograph does not really do it justice because the red I saw with my eyes was a more pure fire engine red, while the red in the pic leans towards orange.

I suspect that is a side effect of the camera's sensor when presented with such blindly bright red sunlight.

Very poetic Kenny . Sound is not dependent on someone hearing it.

It's in cases like this were I realize I should have paid more attention to my classes in optics . Honestly light constituting both a wave and a particle and then quantum mechanics made physics lose it's charm for me.

Hmm where do we see dispersion, inside the diamond or outside the diamond?

I mean that the dispersion we see from diamonds is due to the refractive index of the material and the cut of the diamond affecting the angles thus separating the light into its different wavelengths. So from what I understand the body color of the diamond will not affect it's dispersion (assuming that the minute amounts of impurities that cause some colors have not affected the RI) and thus it bears no relation on what actual colors will come out of the diamond, however the body color of the diamond may act as a filter on our perception of the colors. At least that is what I recall.

By the way, I do know what attenuate means. It may not always seem like it, but I am considered to be fluent in English .

Edited since I can't spell .

 

[kenny]

Good question.
If light breaks up into all those colors only when the light is leaving the diamond the body color should not affect what we see.

I googled this up which says light breaks up when the light enters the diamond. (actually when it passes from one medium to another")
(I assume it must happen once again as the light leaves the diamond.)

http://www.physlink.com/Education/AskExperts/ae184.cfm

SNIP

A light ray is refracted (bent) when it passes from one medium to another at an angle and its speed changes.
At the interface, it is bent in one direction if the material it enters is denser (when light slows down) and in the OTHER direction if the material is less dense (when light speeds up).
Because different wavelengths (colors) of light travel through a medium at different speeds, the amount of bending is different for different wavelengths.
Violet is bent the most and red the least because violet light has a shorter wavelength, and short wavelengths travel more slowly through a medium than longer ones do.
Because white light is made up of ALL visible wavelengths, its colors can be separated (dispersed) by this


ENDSNIP

So white light is broken up into the rainbow of colors as it enters the diamond so the body color of he diamond will have a filtering effect on the light that gets out of the diamond.