Diamond Colours

[KobiD]

With all the talk of colour I've seen popping up lately, it got me a little curious. I'm new to the forum, and green in terms of diamond exposure. The mathematical aspects I've got no issues working with. So in saying that, I hope I'm not breaking any forum rules with this thread.

Attached photos are courtesy of James Allen, taken through a screen shot. All diamonds have their description below. Prices removed as not required. All are GIA graded, with exception to the top right H which is has an IGI cert. These diamonds weren't selected to make a case. I simply chose 3 colours with ideal/ex cut properties and allowed them to sort by default.

As you can see, there is considerable colour variation between the images, and across the colour sprectrum. The top H appears similar to the lower J. The J's and I's almost appear imo to be the clearest/carry less colour than the rest in this sample, which leads into the next part.

My limited exposure has proven diamonds very difficult to capture in photos, colour even more so. Are the variances seen here more to do with the actual photographs, or the diamonds themselves, or does the particular grader play a bigger role than a lot of people give credit for?



Personally, I think the photographs may be the difference and would trust the graders call over the picture.. simply due to the AGS0 stone I recently purchased. It was on the less clear side of the scale when viewed online. It was an I which appeared closer to J, but in person even when set and viewed from the side it appears colourless to my naked eye. Its also set in yellow gold which likely enhances the diamond in comparison to if it were in white.

 

[darkfury18]

I'm currently researching the same issue. Besides the color grade, they also have a tone, typically yellow, gray, and brown. A diamond with a brown tone will naturally look darker than a yellow one in the same color grade. I'm not sure if that's what is seen in the example or even if these tones are visible in the near colorless grades...

 

[iota15]

It's the picture.

While there may be some minor variations between good graders with the same set of master stones, good companies like GIA and AGS should be consistent in the colour gradings calls even between graders. Aside from being well-trained, they have a set of master stones to compare the stone being graded with.

In the JA videos, it can be anything from the photographer, or more likely, the environment that they're being photographed in. The photographer's clothes, the background, the paint colors, the color of the camera - all of those things will affect how the diamond looks from the side through a video.

 

[Texas Leaguer]

Kobi,
Very interesting thread you have started!

As darkfury mentioned, one of the things illustrated in your images is the difference in appearance between diamonds with a yellow hue and those with a brown hue. They make slightly different impacts on our eyes/brains.

As Iota mentioned,variables in the lighting environment and camera specs of the capture will have a significant role in what we see in the image. As well as post-capture editing that is necessary for posting on the web. Therefore, the color call made at the lab in a controlled manner is to be trusted over any photo evidence.

But your study is interesting because it is one vendor (presumably photographed in a relatively consistent manner), the stones are all about the same size, and they are all shot from the side. The deviants seem to be the browns and they seem to deviate dramatically.

I will have some additional thoughts later in the day when I have some time. Hopefully some experts will come in in the meantime.

 

[akoya]

thats what i have noticed too
however for some of the brown tones, the cert will indicate brown

 

[KobiD]

I agree with all that has been said thus far. A couple of the stones definitely have a more chocolate hue which appears to be clearly caught by the camera. The H on the top right appears to show more of a gray tone compared to the I below, or the J beside it. It could also be reflections of the inclusions (it is an I1).

These are from JA 360 degree shots, aligned roughly the same. I would imagine to capture these images JA would be using a machine/workstation purposely built and as such the conditions should be somewhat controlled. By comparing the backgrounds and lighting effects it would suggest this as well.

It could be a matter of the camera simply capturing more than the eye can see (in the same way it does with inclusions).

 

[Rockdiamond]

I agree with Bryan- interesting thread!
Based on the type of equipment available to take pictures of diamonds: Its unlikely the photographers clothing would have affected the pictures.
But other camera, or lighting settings may have affected the pictures.

Another interesting aspect involves color grading itself.
If we compare two correctly graded D color diamonds the potential differences we'd see are minor- but still possible. This can be due to differences in the material itself.
As we go down the scale, introducing more and more color, the potential variation from stone to stone becomes far greater.
We'd have differences based on the tint bring the stone down in color, as well as the differences in the material itself.
So, if we look at 10 correctly graded J color diamonds, and 10 corrctly graded D color diamonds, the J's will be all over the board while the D's remain fairly consistent.
Go down to M color and the differences become even wider.
Continue down the scale to Fancy Light Yellow, and you can find two stones, both GIA graded, with night and day differences.

 

[Texas Leaguer]

I agree with all that has been said thus far. A couple of the stones definitely have a more chocolate hue which appears to be clearly caught by the camera. The H on the top right appears to show more of a gray tone compared to the I below, or the J beside it. It could also be reflections of the inclusions (it is an I1).

These are from JA 360 degree shots, aligned roughly the same. I would imagine to capture these images JA would be using a machine/workstation purposely built and as such the conditions should be somewhat controlled. By comparing the backgrounds and lighting effects it would suggest this as well.

It could be a matter of the camera simply capturing more than the eye can see (in the same way it does with inclusions).

I agree with your observations and I think the last statement could be a factor. I am not sure exactly what the mechanism would be but I think it is possible that the brown hue could "trick" the camera into an exposure that accentuates the darker tone.

There is a general sentiment in the trade that light brown stones face up a bit whiter than the same saturations of color in the yellow hue. At the same time I believe it is possible that they could actually look darker than the same saturations in yellow when viewed from the side.

Considering that hue is an additional variable in color grading, even in the normal range (D-Z), one can easily understand how grading variances can happen between labs and even within the same lab.

 

[John P]

Are the variances seen here more to do with the actual photographs, or the diamonds themselves, or does the particular grader play a bigger role than a lot of people give credit for?

All of the above.

Regarding photos & videos: Even with standardized setups, remember that saturation and even body-tone can be influenced by strength and evenness of lighting, white-balance settings and f-stop/exposure/focal depth variances where shadows have more impact in X size/zoom - versus Y size/zoom. The diamond is not static either, it's rotating, which can impact still-capture moments in different ways. Lighting is especially key. Is there any UV? If two or more setups are in-use are the bulbs the same strength, the same color-temperature, etc?

Now account for different monitors: When I view this on my phone I don’t see nearly the difference I do on my tablet, but when I place my tablet by my 26-inch monitor the images are actually more similar to the phone again. Crazy tablet.

Regarding grading: The diamond is face-down, viewed from the side to see the body’s true color. While you’ve “still-captured” a side-view the very act of rotating removes a consistent static view. Also, saturation and tone happen on a sliding scale. There's a lot of "range" in the bandwidth we consider "J color." This is all-important to a human grader, and probably very difficult to translate using only 256 colors (standard for the web). In short, our eyes see far more.

Personally, I think the photographs may be the difference and would trust the graders call over the picture.

I could have just said “me too” I suppose.

By the way, the old-timers here can tell tales of crazy-lab-angst over the years in the effort to "standardize" lighting & environments for live color grading. It is incredibly complex, even in real-life. I believe a photo or video setup is best used to get you in some kind of ballpark. I think those you posted serve that purpose to a good degree. But I'd rely on the description of a trusted gemologist over any 2D lens-produced picture, simply due to the variables I've read here, some more I've listed, and others that have probably been left out.

 

[Texas Leaguer]

Are the variances seen here more to do with the actual photographs, or the diamonds themselves, or does the particular grader play a bigger role than a lot of people give credit for?

All of the above.

Regarding photos & videos: Even with standardized setups, remember that saturation and even body-tone can be influenced by strength and evenness of lighting, white-balance settings and f-stop/exposure/focal depth variances where shadows have more impact in X size/zoom - versus Y size/zoom. The diamond is not static either, it's rotating, which can impact still-capture moments in different ways. Lighting is especially key. Is there any UV? If two or more setups are in-use are the bulbs the same strength, the same color-temperature, etc?

Now account for different monitors: When I view this on my phone I don’t see nearly the difference I do on my tablet, but when I place my tablet by my 26-inch monitor the images are actually more similar to the phone again. Crazy tablet.

Regarding grading: The diamond is face-down, viewed from the side to see the body’s true color. While you’ve “still-captured” a side-view the very act of rotating removes a consistent static view. Also, saturation and tone happen on a sliding scale. There's a lot of "range" in the bandwidth we consider "J color." This is all-important to a human grader, and probably very difficult to translate using only 256 colors (standard for the web). In short, our eyes see far more.

Personally, I think the photographs may be the difference and would trust the graders call over the picture.

I could have just said “me too” I suppose.

By the way, the old-timers here can tell tales of crazy-lab-angst over the years in the effort to "standardize" lighting & environments for live color grading. It is incredibly complex, even in real-life. I believe a photo or video setup is best used to get you in some kind of ballpark. I think those you posted serve that purpose to a good degree. But I'd rely on the description of a trusted gemologist over any 2D lens-produced picture, simply due to the variables I've read here, some more I've listed, and others that have probably been left out.

Good stuff John. This discussion got me thinking and I would like to get your opinion on this:

Because of tonal differences between brown and yellow stones in the normal range, do you think that between stones of the same color grade that brown hues 'show" their color more than yellows from side view?

The implication would be that while the stones essentially face up the same, yellow would be preferable in say the (I-J-K) range,if the diamond is to be set in mounting that will be highly revealing of the side view of the diamond.

 

[KobiD]

Great response John. I hadn't even considered such variables as multiple photography setups and possibility of lighting changes in relation to bulbs etc. As you've stated, there are very many more that haven't been listed. Differences between screens, resolutions, display drivers, etc are very real also, as are how colours are interpreted by the individual. There is no doubt that its near impossible to accurately gauge the colour of a diamond based purely off a photograph.

My thread was more in relation to the variations seen between stones. It would be interesting to see some comparisons between said stones in a controlled environment, or even to have them graded through as a group and see if there would be any variance picked up.

As above, the diamond I recently puchased through JA showed more of a yellow tone and was graded as an I. Comparing it to others pictures it does look more J. In person, I can't pick up any yellowing in it, and thats after being set in yellow gold with a ring that showcases the side view of the stone.

In the other threads with people discussing the warmer colours, I wonder if the tone of the stone is also having a particular impact along with the colour grade. I would say its very possible.

 

[John P]

Good stuff John. This discussion got me thinking and I would like to get your opinion on this:

Because of tonal differences between brown and yellow stones in the normal range, do you think that between stones of the same color grade that brown hues 'show" their color more than yellows from side view?

Yes. It depends on tone and saturation. A hint of light brown in top cape colors may be invisible, but the same hint gets more visible as you near DEF. The darker the tone, the easier it is to see.

When a diamond grading report cites the presence of fluorescence any gemologist knows that SBF and VSBF require further examination to assess the implications. To that end, many suppliers write "Not milky" in their own notes to imply it's been checked... When it comes to color I'm increasingly seeing VLB, LB or BR in suppliers' notes to disclose the presence of tint. Some Indian dealers are now also noting NT (no tint) or NBNG (no brown no green) for all near-colorless diamonds free of tint - they say "tinge" - because the question has become somewhat compulsory in the Asia-Pacific, where the ratio of brown and green is higher. No BGM is also used, meaning no brown, green or milky.

The implication would be that while the stones essentially face up the same, yellow would be preferable in say the (I-J-K) range,if the diamond is to be set in mounting that will be highly revealing of the side view of the diamond.

Logical.