Photographing color change garnets? Questions!

[katharath]

This post is really directed at those of you who have had color change garnets in hand and have tried to photograph them. I've owned several small pairs ranging from 2 mm to 4 mm, and then a couple of larger rounds (a 1.12 ct, 6.3 mm), and I just bought and received another that is 1.47 ct and 6.7 mm (it's the one Gene has had up on his site for awhile! I've wanted it for a long time and Gene gave me a great deal on it, too good to pass up for me).

Most of my cc garnets change from the blue to blue green to purple color. The one I just got from Gene is much greener, it's a green to purple changer. So here is my question: why does it seem impossible to get the daylight color to show up in photos? I've tried using my iPhone and a digital camera, on all of my cc garnets. Each time I try to photograph them, as I look at the gem on my hand it shows its daytime color; but when I look through the camera the gem will show a different more purple color, and when I snap the pic, it shows up as this color - a much bluer color than the gem actually appears in real life. For example, with the Gene stone - it looks VERY green IRL in daytime; yet the pics show it as a blue almost purple color. But the color in the pics is NOT the color that the gem shows in candlelight/incandescent. That purple is yet a different color. And then, when I try to take pics of the gem in candlelight/incandescent, those pics DO show the true color. What is up with that? Why and how does is it that it's possible to get the incandescent pics to show up accurately, but not the daytime color pics? Does anyone know? Is there a way to get cc garnets to show their true daytime color in photos, and does anyone here know it?

I really hope this post at least makes some sense. I've thought about posting this for months but have finally done it, mostly bc I'd love to be able to take accurate pics of my new Gene stone, but it seems impossible! I suppose I could ask Gene, I just didn't want to "bother" him with all of these questions. Hoping someone has some tips and that I don't come across as sounding like a nut, lol! At the very least it would be good to hear that I'm not the only one who has difficulties photographing these gems.

 

[Quantz Studios]

Have you put the pictures on the computer to look them yet? My camera does a similar thing with my CC garnet (greenish blue-to-red pink)- the colors look pretty far off on the camera screen but when put on the computer and a simple white balance shift if necessary and it looks like it does in the hand. Same thing with an amethyst I have been working on- On the camera screen it looks like a tanzanite, but put the picture on the computer and it's the same purple it is in life. And I know my monitor is calibrated properly, so it's something with the camera. Some of them are like that- I just have to trust my instincts and my eye when photographing because what I see on the camera screen may look like crap, but actually is a good picture.

 

[katharath]

I haven't actually put them on the computer. I will try it - but I don't think it will make any noticeable difference with my Gene gem. The reason I say that is that in daytime, it's a dark green, almost tsavorite like. In the pics I take, it looks dark purple gray. No one would even think it was the same gem! It's very odd.

 

[katharath]

Thanks for the input though! I'll post some pics in here later tonight from my PC.

 

[kenny]

I'd be careful to white balance for each kind of light you use.
Next I'd place the gem on a pure white background, better yet a gray one.
Then in post-processing, re-whitebalance the background to pure white or gray.

Then display both pics side by side.
If the gray backgrounds do not match exactly, make them match.

Now you have removed the color inaccuracy that the photographic process can introduce ... it is time to look at the gem itself in each pic.

 

[katharath]

Thank you Kenny! Sounds like good advice, I will give it a try for sure!

 

[minousbijoux]

As you know, Kenny is THE man when it comes to photography. Kenny now a question for you. I often see when someone is selling a color changer like an alexandrite that they have used the same set up (same wall, backdrop, and neutral color that the stone sits on) for each photo, but just completely switched out the light source. At least thats what I assume they are doing, because everything looks exactly the same, but in one picture, every thing around the stone looks like it is a cold light with a bluish tint, and then in the next pic, every thing will look much warmer in hue, almost like a yellow white. In these cases, I know the backgrounds are supposed to look white, but they don't - quite. Does this mean they are exaggerating the color change properties of the stone, that in order to get accurate readings of the stone's true color, they would need to correct the color balance in post production?

I have been wanting to ask this question for the longest time - so thanks!

 

[Richard M.]

Does this mean they are exaggerating the color change properties of the stone, that in order to get accurate readings of the stone's true color, they would need to correct the color balance in post production?

I have been wanting to ask this question for the longest time - so thanks!

I can answer that, at least in regard to my own methods. Frankly, I don't understand Kenny's technique -- he's way ahead of me in that regard and I'd like to learn more specifically about how he does what he describes.

As for differences in warm vs. cold hues, the first image is made with daylight equivalent lighting that's approximately 5,000 K - see this chart http://www.mediacollege.com/lighting/colour/colour-temperature.html This type of lighting has lots of blue wavelengths. The attached image of a stone I sold long ago illustrates the technique I use.

The photo set-up is left exactly the same but an incandescent equivalent light is substituted for the daylight bulb, usually around 1 to 2 K., which is strong in red wavelengths. It's the absorption of the daylight or candlelight wavelengths that causes color change in gems.

This method is a completely honest attempt to show how the stones look in daylight vs. candlelight/incandescent lighting. I've always been most interested in showing the stone's color accurately, not the background. But apparently there's a way to do both.

One of the biggest areas of confusion about CC gems comes from viewing them in mixed lighting, say under an incandescent light next to an open window at noon. Neither color will be "pure" under those circumstances. And there's a huge difference in the actual color temperatures of various fluorescent lights. In my opinion the only true evaluation comes from comparing a stone's color in shaded noon daylight vs. candlelight or equivalent. That's very hard to do and it's why some dealers (not me!) resort to PhotoShopping stones with colors they believe to be accurate.

Richard M. (Rick Martin)

 

[Quantz Studios]

Minou, I have taken many pictures of CC stones and if I adjust the white balances properly the backgrounds come out nearly identical. But you have two different wavelengths of light- one more whitish/bluish and one more yellow. You will notice this in most pictures much as the same as you will notice them if you turn each type of light on in your house- In my opinion. I am not an expert or a pro. But I have been able to get the backgrounds nearly the same color and the stone still stay true to life as I can get it. Again, I am no pro with pictures... I use a point n' shoot and know the basics to get the settings ideal for the situation, have white balance set on "auto" or the appropriate setting for the lighting (whichever looks best) and then re-adjust once on the computer. I also like doing mixed lighting shoots with my CC stones. I've included examples of both- the one with separate pictures I took with a different camera a while before the mixed lighting- you'll notice a difference in the incandescent color between the two. This stone is alll mine and NFS so there aren't any trade status conflicts here.

 

[minousbijoux]

Katharath: I hope you don't mind that I jumped in here a bit.

Rick and Ryan: thanks so much for your responses. Ryan: I definitely see from your images that you are able to capture the color shift properties in the way you did it, but my next question for you would be in doing it this way (which is more the Kenny way), do you think the colors of the stones turn out to be a fair representation of what you see?

Rick: same question for you. Huge difference in the appearance of the stone - in fact that one would be a color changer if the colors are accurate. Do you see (or did you see) these colors? In other words, do you think these photos portrayed a fair representation? This all is so facinating to me.

Kath: can't wait to see what methods you try now!

 

[Quantz Studios]

Minou, like I said the first picture is older and I am not happy with it. The colors are a fair representation, but if I was to set up that same photo with my new camera and lighting i'd be able to capture them better. Back then I just used a regular bulb and random spaghetti bulbs. I'm a perfectionist and will tinker with settings and lighting and whatnot until it's nearly perfect to life. That's just how I am. These days I use either (incan)Reveal bulbs or a halogen desk lamp or both at the same time- Whichever makes the stone look more like life in both lights... and my Ottlight daylight equivalent spaghetti bulb. But that first one is nothing like the second photo. The second photo is just two different light sources on each side of the stone, holding the camera and snap. No reflector, no light box, nothing. I'd say that second picture is a near dead-match to the colors in life- On my monitor anyways... though it is more lively than the picture suggests. That's hard to capture. Camera- one lens. Us- two lenses.

As far as Ricks picture- I know what material that stone is and have seen many of them and if you look at the stone- Those are typical colors for that material that you will see in life- But Rick will have to chime in on their accuracy. But in my experience i'd say those pictures are a fair representation.

 

[Richard M.]

Rick: same question for you. Huge difference in the appearance of the stone - in fact that one would be a color changer if the colors are accurate. Do you see (or did you see) these colors? In other words, do you think these photos portrayed a fair representation? This all is so facinating to me.

The stone colors are accurate and a very fair representation -- IF another viewer uses exactly the same (correct) lighting I used. That's why I went to so much trouble to find exactly the right color temperature lights. Chances are they would not, though, and that leaves the door open for all sorts of misunderstandings. That's why I sell CC stones in-person only, not on line. There's simply too much confusion about how and why they do what they do. These things are easily illustrated in-person -- on a sunny day at least

Yes, that garnet is definitely a color-changer although I really like the so-called "color-shift" stones too if the hues are attractive. Nice ones are really scarce. In addition to mixed lighting there's at least one more reason consumers are confused by CC gems. I don't know how many times I've read on line that CC gems show different colors between "fluorescent" lighting and daylight. That's technically somewhat true but it ignores the fact that "fluorescent" light varies enormously in color temperature. The Ott Light, promoted as a daylight equivalent, is not in my opinion. Often when grading CC garnets I find the Ott Light color is entirely different than the actual daylight color. Ditto for other fluorescents like "cool" or "warm."

Also, the bulbs we call "incandescent lights" hadn't even been invented when the color-change properties of Alexandrite were discovered. The jeweled ladies of the Imperial Russian aristocracy had only real candlelight to show off the lovely purple-red hue of their new gems. There's a very big range of "warm" color temperatures as well, and they have a big effect on a CC stone's appearance.

Richard M. (Rick Martin)

 

[Quantz Studios]

I have to disagree with you on the Ottlite Rick, as far as my opinion of its accuracy in recreating daylight. At least, it matches the daylight here in the desert better than any other CFL bulb i've tried. I take pictures of everything under those Ottlites and even offer some stones with different daylight pictures too. I've had more than a handful of people reply that the stones appeared in the hand as they did in pictures. So, I'm just referring to the Ottlite'e color representation out of my own experiences and results. Everyone's got their own things that work for them.

 

[kenny]

As you know, Kenny is THE man when it comes to photography. Kenny now a question for you. I often see when someone is selling a color changer like an alexandrite that they have used the same set up (same wall, backdrop, and neutral color that the stone sits on) for each photo, but just completely switched out the light source. At least thats what I assume they are doing, because everything looks exactly the same, but in one picture, every thing around the stone looks like it is a cold light with a bluish tint, and then in the next pic, every thing will look much warmer in hue, almost like a yellow white. In these cases, I know the backgrounds are supposed to look white, but they don't - quite. Does this mean they are exaggerating the color change properties of the stone, that in order to get accurate readings of the stone's true color, they would need to correct the color balance in post production?

I have been wanting to ask this question for the longest time - so thanks!

IMO, if the same backdground is used for both pics then the background should look identical in hue/tone/brightness/saturation etc.etc.etc. in both pics.
Only then do you have an apples to apples comparison of the gem in different lighting
If not the photographer did not what balance properly before/and or /after the pics were taken.
Also allow a sufficient amount of them for the gem to fully 'change color' and adjust to the new light source.

The background did not change color in real life so it must not change color in final pics regardless of light source used.

Only when the same background is used and the background looks identical in both pics can you believe the color change of the gem is accurate.

Caveat: I know nothing about color-changing gems, but I know a thing or two about photography.

BTW, backgrounds would ideally be a neutral gray with 18% reflectance purchased at a photography store that caters to professionals.
The reason 18% gray is a magic thing is all cameras's light meters attempt to expose each pic to a reflectance of 18% gray, whether you are shooting a white horse in the snow at noon on a sunny day or a black horse in a dark barn.
Stupidly, both pics, properly exposed by the best cameras in the world will come out showing the horse looking a gray the reflects 18% of the light striking it.

If your background is white or black the exposure will be pushed to one extreme and you will not be capturing maximum detail regardless of how much work you do to fix the exposure in post-processing.
Of course we are talking about two separate things, hue and exposure.

Here is an example of an 18% gray card.

http://www.bhphotovideo.com/c/product/760178-REG/Dot_Line_DL_0510_Digital_Color_Balance_Cards.html

 

[Richard M.]

Well 'Bender, maybe I shouldn't believe my lying eyes, as Groucho once commented. I have repeatedly checked some CC garnets with Ott Lights and then immediately afterward in shaded sunlight and observed very different color results. I don't doubt what you say but I think it's possible that some CC stones may vary in chemical composition sufficiently that they react to certain lights of the same general type differently.

I first noticed that variation when color-grading a batch of CC garnets from Tanzania. I made color notations at night, using a standard hi-intensity incandescent lamp vs. an Ott. The next day I checked the results against actual sunlight and was very surprised to see 3 different colors: incandescent, Ott and real daylight. I guess mileage can vary.

Richard M. (Rick Martin)

 

[kenny]

Does this mean they are exaggerating the color change properties of the stone, that in order to get accurate readings of the stone's true color, they would need to correct the color balance in post production?

I have been wanting to ask this question for the longest time - so thanks!

I can answer that, at least in regard to my own methods. Frankly, I don't understand Kenny's technique -- he's way ahead of me in that regard and I'd like to learn more specifically about how he does what he describes.

As for differences in warm vs. cold hues, the first image is made with daylight equivalent lighting that's approximately 5,000 K - see this chart http://www.mediacollege.com/lighting/colour/colour-temperature.html This type of lighting has lots of blue wavelengths. The attached image of a stone I sold long ago illustrates the technique I use.

The photo set-up is left exactly the same but an incandescent equivalent light is substituted for the daylight bulb, usually around 1 to 2 K., which is strong in red wavelengths. It's the absorption of the daylight or candlelight wavelengths that causes color change in gems.

This method is a completely honest attempt to show how the stones look in daylight vs. candlelight/incandescent lighting. I've always been most interested in showing the stone's color accurately, not the background. But apparently there's a way to do both.

One of the biggest areas of confusion about CC gems comes from viewing them in mixed lighting, say under an incandescent light next to an open window at noon. Neither color will be "pure" under those circumstances. And there's a huge difference in the actual color temperatures of various fluorescent lights. In my opinion the only true evaluation comes from comparing a stone's color in shaded noon daylight vs. candlelight or equivalent. That's very hard to do and it's why some dealers (not me!) resort to PhotoShopping stones with colors they believe to be accurate.

Richard M. (Rick Martin)

Tip: Always look at the background before you look at the gem.
Richard I love you dearly and please don't be offended I'm using your pic, but it's a perfect example to shed light on something.

Notice the difference in the background color of the pics above.
It is especially noticeable right where the pics meet.
The 'white' background on the left is pinkish, while the same "white" background on the right came out greenish.
That shouldn't be.
The same background should always be identical in hue, saturation and tone, even under different light sources.
If the images are properly white balanced the background WILL look identical.

Forgive the caps but ... SOME GEMS CHANGE COLOR WHEN THE LIGHT SOURCE CHANGES; BUT BACKGROUNDS NEVER CANGE COLOR!

If the same background used but its color is different in the final pics, then the pics cannot possibly accurately depict the color change of the gem itself.
Color-change gems change hue with the light source backgrounds do not, cannot, should not.

You can address this anomaly in one of two ways, or both.
You can do a more accurate white balance before taking the pic or correct it in post processing with Photoshop or another program.
Fixing it in post is not cheating, it's correcting and compensating for an inadequate camera or operator error while taking the pic.

It is preferable to prevent this from happening by doing a better white balance before taking each pic.
Many cameras have settings for fluorescent, tungsten, sunny, cloudy, etc., but those are sloppy averages.
When spending a zillion bucks for a real Alexandrite you want better accuracy of color representation.

Florescent and tunsten lights come in MANY colors ... and daylight varies greatly with time of day, weather, season, and latitude on the globe.
Near the equator sunlight passes through less atmosphere than near the poles, so the color of the light will be different.

Better cameras allow you do to a MANUAL white balance.
That's when you place a white, or better yet a calibrated 18% reflectance gray card, over the gem prior to taking the pic and press the MANUAL WHITE BLANCE button on the camera.
Do this AFTER your light source has been turned on a while, since the color of light all electrical sources changes as they warm up.

Richard, I took your pic and did a quick an dirty post-processing white balance, to attempt to match the background.
Your background itself has many colors in it, but this is just a quick example.
Please notice the 'white' background in the bottom pair, the pair I white balanced, is closer to matching than the original pair above.
Again, only after matching the background should you look and and judge the gem's color change.



Again, light sources cannot change the color of backgrounds, only of color-change gems.

 

[Richard M.]

Kenny, maybe in a day or two my anger will subside enough to allow me to write a calm response to you. Maybe not. I'm willing to admit error when I'm wrong and learn new things but I won't be condescended to.

Richard M. (Rick Martin)

 

[kenny]

Kenny, maybe in a day or two my anger will subside enough to allow me to write a calm response to you. Maybe not. I'm willing to admit error when I'm wrong and learn new things but I won't be condescended to.

Richard M. (Rick Martin)

Richard I'm sorry I made you angry.

I attempted to present facts and support them and give consideration to your feelings.

Take your time and respond if and when you are ready.

I'm also willing and open to learning new things, but will never entertain the suggestion that it is okay for a white background to look pink in one pic and green in another, especially when pics that lean towards those hues help to make a gem seem more valuable.

 

[Quantz Studios]

Well 'Bender, maybe I shouldn't believe my lying eyes, as Groucho once commented. I have repeatedly checked some CC garnets with Ott Lights and then immediately afterward in shaded sunlight and observed very different color results. I don't doubt what you say but I think it's possible that some CC stones may vary in chemical composition sufficiently that they react to certain lights of the same general type differently.

I first noticed that variation when color-grading a batch of CC garnets from Tanzania. I made color notations at night, using a standard hi-intensity incandescent lamp vs. an Ott. The next day I checked the results against actual sunlight and was very surprised to see 3 different colors: incandescent, Ott and real daylight. I guess mileage can vary.

Richard M. (Rick Martin)

Absolutely. I'm not saying your eyes are lying. Some stones show a different shift in color in every lighting you take it in. Even daylight at different times and different parts of the world is different. So, it can get pretty complex especially with color changers.

 

[minousbijoux]

You know, I asked the question initially because it is NOT clear to me whether the change in background color necessarily always means its influencing the gem color and I wanted to hear more about it.

In theory, Kenny, what you are saying makes sense, which is why I asked the question to begin with and wanted to hear from you on it. But on the flip side, I believe there is something that happens somewhere along the line from the light entering the stone to the properties of the stone and the way the light is reflected out, to the camera and its interpretation, to the photo, to our eye and our mind's interpretation that causes changes.

But there have been way too many people who, in response to our pointing out that the white background has a tint and it therefore must be affecting the color of the stone, have said that that is the closest they could get to the actual color of the stone they see in hand (in fact, I have alienated people along the way for pointing this out). At some point, with so many respected people saying the same thing, I have to think what they are saying is correct. Perhaps there is a difference between the way our eye interprets and the way our camera interprets so that in Rick's case of the color changer, in order for him to get the stone to the closest color he sees, he must have a tinted background. I totally get what you are saying Kenny from a purely logical viewpoint as to how things work, but my gut says thats just too easy.

Rick - if you are still here and willing to respond, can you tell us which one is closer to the actual color of the stone - yours on the tinted background, or Kenny's color corrected version (with the understanding that there are limitations to what Kenny can do to alter the color post post production, lol)?

As much as I want to think you're right, Kenny, I think its not as straightforward as we might think it is...

 

[minousbijoux]

Oh, and sorry, Katharath **who has clearly run away and is hiding in a bunker somewhere** for threadjacking your thread; I do hope you find this helpful? If not, perhaps we can take it out of your thread and start a new one...

 

[katharath]

Lol - yeah, I had some new results/pics and was going to share them, but I saw the way things had evolved in here and just thought it might be better to duck out. Not a big deal though, no worries. I think I've found some very helpful info.

 

[Quantz Studios]

Forgive the caps but ... SOME GEMS CHANGE COLOR WHEN THE LIGHT SOURCE CHANGES; BUT BACKGROUNDS NEVER CANGE COLOR!

If the same background used but its color is different in the final pics, then the pics cannot possibly accurately depict the color change of the gem itself.
Color-change gems change hue with the light source backgrounds do not, cannot, should not.

Besides the fact that not everyone has professional photography equipment and editing programs, or the knowledge and/or time or desire to perfect them to a science... AND the fact that the interactions between stone, light and color are not as simply straight forward as we would think or hope- Let alone taking pictures of it...

Sorry, I disagree ... In digital photography we have the luxury to change the white balance and adjust this and that, but our eyes dont do that that I'm aware of. Shine an incandescent light on my living room wall, and the wall is a strong orange-peach. Shine daylight on it or fluorescent and its light pastel peach. Background color changed... How can you say the STONE COLOR isn't accurate to what Rick sees with his own two eyes as compared to the picture, based solely on background color? Do your eyes see a perfectly white background no matter what temperature lighting shines on it? Doubt it.


So, the point, and original question directed towards Rick is, "Is it a fair representation of the color of the STONE?" The color of THE STONE still looks comfortably close and darn near unnoticeably close to me, regardless of your corrected background color. So after all this, we're kinda right back where we started from, eh?


Rick, to me you're still a great guy, a trusted friend and an honest vendor- Regardless of your... 'inadequacies' .

 

[minousbijoux]

In digital photography we have the luxury to change the white balance and adjust this and that, but our eyes dont do that that I'm aware of. Shine an incandescent light on my living room wall, and the wall is a strong orange-peach. Shine daylight on it or fluorescent and its light pastel peach. Background color changed... How can you say the STONE COLOR isn't accurate to what Rick sees with his own two eyes as compared to the picture, based solely on background color? Do your eyes see a perfectly white background no matter what temperature lighting shines on it? Doubt it.


So, the point, and original question directed towards Rick is, "Is it a fair representation of the color of the STONE?" The color of THE STONE still looks comfortably close and darn near unnoticeably close to me, regardless of your corrected background color. So after all this, we're kinda right back where we started from, eh?


Rick, to me you're still a great guy, a trusted friend and an honest vendor- Regardless of your... 'inadequacies' .

Well said, Ryan. Your example of what your eye sees in the way of color on the wall is what I was trying to say. After all, that is the key ingredient we are talking about here when we talk about a color change/shift stone; that the type of light affects the color of the stone...

 

[kenny]

You know, I asked the question initially because it is NOT clear to me whether the change in background color necessarily always means its influencing the gem color and I wanted to hear more about it.

In theory, Kenny, what you are saying makes sense, which is why I asked the question to begin with and wanted to hear from you on it. But on the flip side, I believe there is something that happens somewhere along the line from the light entering the stone to the properties of the stone and the way the light is reflected out, to the camera and its interpretation, to the photo, to our eye and our mind's interpretation that causes changes.

But there have been way too many people who, in response to our pointing out that the white background has a tint and it therefore must be affecting the color of the stone, have said that that is the closest they could get to the actual color of the stone they see in hand (in fact, I have alienated people along the way for pointing this out). At some point, with so many respected people saying the same thing, I have to think what they are saying is correct. Perhaps there is a difference between the way our eye interprets and the way our camera interprets so that in Rick's case of the color changer, in order for him to get the stone to the closest color he sees, he must have a tinted background. I totally get what you are saying Kenny from a purely logical viewpoint as to how things work, but my gut says thats just too easy.

Rick - if you are still here and willing to respond, can you tell us which one is closer to the actual color of the stone - yours on the tinted background, or Kenny's color corrected version (with the understanding that there are limitations to what Kenny can do to alter the color post post production, lol)?

As much as I want to think you're right, Kenny, I think its not as straightforward as we might think it is...

I don't know anything about color-changing stones.
I do know a white background should, and can always, appear white.
If a white background is not white the picture is broken, if the purpose of the pic is to communicate the color of something on the white background.

If the results of the gem do not match our memory of how the stone looks I'd keep in mind that the brain/eye system is amazingly flexible at fooling us and we may not even be aware of it.
It compensates for the color of the light source, tungsten, fluorescent, mid day sun, evening sun, cloudy sky, etc.

I used to work in a lab that did a special kind of photo-chemical-etching process.
The light had to be intensely yellow.
When you walked into the room the yellow hit you in the face like a ton of bricks and was very disorienting.
After a short time your eye/brain system just adjusts and you no longer notice it.
Then when you walk out of the lab into a room with 'normal' light everything looks purple for a few minutes.

Why am I bringing this up?
Just to add that a human's perception of light and color may not be as neutral and believable as we'd like to think.
Our eyes trick us so a white piece of paper we carry around into different light sources always look white.
It's magic, but it's problematic when we attempt to expect photography to do the same thing.

I'm not offering any answer to what I think I'm reading as a mysterious problem of photographers not being able to accurately photograph color change gems.
I'm just pointing out that having correct white balance is basic, and background color is how you judge it.
You don't change the color of the entire image so the gem gets to the color you think you remember ... and evidence that this was done will be the background color not matching on the two images.

If the background hue matches but the gem still looks the wrong color, I have no explanation why.
But, it's a very intriguing problem.

I may buy a couple inexpensive color-change gems and experiment with photographing them.
Which gems would be good candidates?

 

[corundum_conundrum]

djraregems might have some color-change garnets at experimental prices:

http://www.djraregems.com/colorchangegems.html

If you wanna splurge, Gary's bishop has a good shift!

http://www.finewatergems.com/garnet.html

Ebay for really cheap and ugly things.

 

[bobsiv]

Of course backgrounds change color. Everything changes color depending on the wavelength of light shining on it. It's not like there's a physical/chemical change that takes place in a cc gem when different light sources are used, it's a matter of absorption and perception. Like Ryan says, if you shine a blue light on a white wall, it should look blue and a picture of it should look blue.

I guess I can see the argument for color-correcting the backgrounds to be similar since the human eye and brain does a lot of 'white balancing' of its own, but in some sense I would say that's a less accurate way to show color change. The goal is to accurately show how something looks in different colors of light, which means the background can look different too if that's what it takes to show the stone acurately. In my opinion.

 

[minousbijoux]

Of course backgrounds change color. Everything changes color depending on the wavelength of light shining on it. It's not like there's a physical/chemical change that takes place in a cc gem when different light sources are used, it's a matter of absorption and perception. Like Ryan says, if you shine a blue light on a white wall, it should look blue and a picture of it should look blue.

I guess I can see the argument for color-correcting the backgrounds to be similar since the human eye and brain does a lot of 'white balancing' of its own, but in some sense I would say that's a less accurate way to show color change. The goal is to accurately show how something looks in different colors of light, which means the background can look different too if that's what it takes to show the stone acurately. In my opinion.

Yes! It seems we're at the point where we need someone who specializes in optics to enter the fray and help us understand what would ultimately be the best method for the human eye to see "accurate" color. Any takers?

 

[kenny]

bobsiv, I hear what you are saying and this subject can touch on the realm of Zen, where nothing is right or wrong. Everything just IS.

I studied art a bit.
In my beginning drawing class the teacher said, "Draw what you see, not what you know."
That sounded absurd ... till I tried to draw.
Drawing what you see easier said than done because we all trade in seeing for knowing long ago.
We had to; if we didn't our brains would explode processing excessive input.
As I progressed as an artist I developed a saying, "Drawing is easy, seeing is hard."

Teacher said since you know a tabletop is perfectly round you will tend to draw it more round than you see it when viewing it from at an angle.
Letting go of what you know and turning your eyes back on takes practice.

The human brain also messes with the color data it gets from the eye.
It knows a white object is still a white object regardless of the light it is seen in.
That's why it 'looks' white in every light ... yes if the light source is a very strong blue the white paper will 'look' blue to the human.
But with light sources that are more reasonably near middle-white the white paper will look white to the live human.

Something revolutionary happened in 18th century France that informs this discussion on color perception and portrayal via a medium.
The impressionist artist starting interrupting this involuntary automatic eye/brain process, where the brain prevents the eye from really seeing what is actually there.
They looked at a white wall on a sunny day in part shade and painted what they saw ... yellow and blue.
Everybody knows shadows are black.

The art establishment was shocked and offended, and it took decades for this more accurate way of seeing color to catch on.

Notice the artist used black paint for the shadows in this 1670 painting.


Look at the sidewalk below in this 1882 painting.
Notice the shadow cast by the bridge and the dog.
The artist used blue paint, not black as in the earlier painting above.



Again a white wall on a sunny day with some shadows cast by trees.
Outside on a sunny day shade is actually illuminated by a huge blue light source ... the blue of the sky.
It took artists hundreds of years to turn their eyes back on and really see what was in front of them all along.

 

[kenny]

Double post.