CIBJO releases Gemmological Special Report: considers process of separating measurable facts from opinion; See Gemological Articles below.
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Tue Nov 12, 2019 12:33 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 50 posts ]  Go to page 1, 2, 3, 4  Next
Author Message
 Post subject: Color Change in Identical Pictures of CC Gemstones
PostPosted: Wed Jul 22, 2009 10:22 am 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Feb 03, 2009 12:19 pm
Posts: 914
Location: California, USA
Hi, Folks,

On eBay and other internet websites, I often come across a color change gemstone whose pictures show exactly same scintillation, reflection and extinction under different lights. Here is an example.

I always wonder if it is possible to take exactly same pictures twice under changed lights. If the camera is firmly supported with a tripod or something, is it really feasible? I suspect they are the same picture that has been photoshopped to show different colors. My take is the stone may actually change or shift the color, but I cannot tell exactly how it changes or what color this stone is under any light.

What do you think?

Mitch

_________________
Best regards,
Mitch

I am a slave to cutting a stone completely free of chips and very much enjoying it.


Last edited by mhuynh on Fri Jul 24, 2009 1:06 pm, edited 1 time in total.

Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 10:28 am 
Offline
Gemology Online Übergoddess

Joined: Tue Nov 06, 2007 3:16 am
Posts: 3170
:lol: :shock: hi mitch, i couldn't honestly tell you about how the pictures were taken/edited. but, i want to share this yellow aquamarine from the same seller with you.

Click for link


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 10:41 am 
Offline
Gemology Online Übergoddess

Joined: Tue Nov 06, 2007 3:16 am
Posts: 3170
:shock: geez, it's one of those looonngg posts.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 10:44 am 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Feb 03, 2009 12:19 pm
Posts: 914
Location: California, USA
Hi, gingerkid,

Yellow aqua? If it is a beryl, should it be called heliodor? The description down there says stone type is "natural tourmaline” as well. I am confused! :?

Mitch

_________________
Best regards,
Mitch

I am a slave to cutting a stone completely free of chips and very much enjoying it.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 10:53 am 
Offline
Gemology Online Übergoddess

Joined: Tue Nov 06, 2007 3:16 am
Posts: 3170
:lol: you're right, mitch, if it is yellow beryl, (that's a big-if!) it would be helidore. didn't catch the tourmaline in the description of the stone. :shock: also, the stone's luster is "sparkling."

this seller has tsavorite galore!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 11:04 am 
Offline
Platinum Member

Joined: Tue Jun 03, 2008 4:40 pm
Posts: 2667
Location: South Dakota
I don't ujnderstand what "100% natural heated" means on the first example

_________________
MrAmethystguy ~ Some jokes just fluorite over my head!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 1:51 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Feb 03, 2009 12:19 pm
Posts: 914
Location: California, USA
Hi, Jeff,
So it is not impossible to take two exact pictures under different lights. But it takes a lot of photographic skills. If the purpose of pictures is confirming a color change in a gemstone, they don’t need to make such an elaborate effort. If one is interested in a color change gemstone represented this way, proceed with caution or check the return policy carefully. Am I right?

Oh, boy, Amguy,
I didn’t mean to pick on this particular seller. They have 100% positive feedback and their prices are pretty good (not for us, but for them!). But there are a lot of funny things going on. I was trying to comprehend from the other side…what is 100% unnatural heated? Hmm…I failed. :smt017

Mitch

_________________
Best regards,
Mitch

I am a slave to cutting a stone completely free of chips and very much enjoying it.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 5:43 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Sat Jul 11, 2009 10:29 am
Posts: 928
Location: USA
Yes it is possible to do, simply by swapping gels or filters on the light source. Is your example posted edited? Yes, I am 99% sure it is. Reason being is even when swapping gels odds are you would shift the light ever so slightly, but the reflections on those two images look identical. When I get on my pc(instead of my phone.... What I am on now) I will check the images with a hex editor and see if they are the same or not for sure, but I highly suspect they are. It is simple to replace colors, swap colors, and adjust hues selectively in photoshop and many other editing programs. The overseas Ebay sellers even overlay fake stars onto sapphire and ruby cabs to make the stars look perfect, lol. Anything is possible with photoshop if you have the knowledge on how to do it!

As for the mastering of light and photography, they are one in the same. In order to truly master the art of photography one must first and foremost master the light! If one has not mastered the light then they have also not mastered photography. Photography is essentially all about the light and capturing the light. Just look at all the masters and the greats in photography, for example, Ansel Adams, they mastered the light and the camera. The camera is useless without the light. :).

As for color changing stones... That is a long explanation, already partially done in the c/c chrysoberyl thread here. But to keep it simple, each and every light source is different. Some sellers use odd lighting like leds(which are all different temps as well as spectrums), and a stone can c/c or c/s under this light change but not another. I have some c/c cz that I can get to change like 4-5 distinctly different colors depending what type of light source I use. Not all lights even allow for the true reproduction of colors to the human eye!

But, always remember, ANYTHING, is possible with photoshop! The possibilities are infinite! If I remember I will post some examples when I get on my computer.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 7:08 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Feb 03, 2009 12:19 pm
Posts: 914
Location: California, USA
Swishman wrote:
In order to truly master the art of photography one must first and foremost master the light!


Nobody has told me before. Somehow I intuitively knew it! :D You confirmed me. Thanks.

Mitch

P.S. I still believe that the pics in the first sample are the same.

_________________
Best regards,
Mitch

I am a slave to cutting a stone completely free of chips and very much enjoying it.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 7:32 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19886
Location: San Francisco
Just because one is using PhotoShop does not mean they are intending to deceive.

Gary Roskin uses PhotoShop routinely to correct color in his photos and he is revered as one of the greatest gem photographers of all time.

Haven't you ever taken a photo of a gem or piece of jewelry only to find your color was completely wrong? :shock:
You can keep taking more pictures, praying for better results, or simply correct the color with photo editing software.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 8:32 pm 
Offline
Gold Member
User avatar

Joined: Wed Sep 06, 2006 1:15 pm
Posts: 1795
Location: canada
Hi Barbra:

Quote:
You can keep taking more pictures, praying for better results,


Before doing that one should thing twice and remember that O.C. is defined as doing the same thing over and over and expecting a different out come :)

_________________
A Chinese proverb says "Gold is valuable, Jade is Priceless."


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 9:09 pm 
Offline
Platinum Member

Joined: Tue Nov 29, 2005 2:02 pm
Posts: 2647
Wonder why my Big Mac or Whopper never looks like the picture?

Some things in life need a little help. Like my Drivers License photo. :P


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 9:45 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Sat Jul 11, 2009 10:29 am
Posts: 928
Location: USA
Barbra, no one said photoshop is bad. I use photoshop on all my images. That is not what is being referred to. What is being discussed is the use of photoshop to mimic the color change instead of showing a real one. Photoshop has legitimate purposes or I wouldn't spend so much $$$$ on it every other release. But it is too often "abused". Once one is experienced with photoshop and its techniques it is not hard to spot fakes. I have been using ps for over a decade and write commercial programs and actions and scripts for it, so I delve fairly deep into the use of it. To clarify, when checking with the hex editor I am not looking for Adobe, but checking the coding of the images to see if they are indeed separately taken images or just one single image edited to fake a c/c, which is what it appears as to me.

As for color corrections, if the person takes the image properly from the start there is NO need to correct color. The only time color correction is typically needed is when the shooter messed up settings in camera at the time of the shot. As in incorrect white balance settings, improper exposure that when pushed up to proper exposure in editing causes a shift in color appearance, etc. Otherwise, if everything is done properly, there is no issue with correcting color the majority of the time. :).


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 10:03 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19886
Location: San Francisco
:) I think it is often inferred that if a gem has been "PhotoShopped" it is somehow deceptive....and it CAN be, but that is not always the case.

You certainly have more sophisticated camera skills than I. I always have to color correct, but I just use the auto focus on a point and shoot CoolPix or Sony.

I just got a new Nikon D90, color is much better but I still need to tweak most of the shots. I guess I'm more comfortable with using software than the manual settings on cameras. :wink:


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Jul 22, 2009 11:21 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Sat Jul 11, 2009 10:29 am
Posts: 928
Location: USA
Barbra,
With the D90 it is real simple. Get yourself a gray card. If not, take a coffee filter and stretch it over the lens so it is nice and smooth, now, follow your manual and set a custom white balance in the area you are shooting the stone. Now you should have pretty darn accurate colors out of camera. :). A gray card is used almost the same, only you sit or hold it in the frame without the coffee filter and set your white balance. Or you can actually even use a white card for this as well, but the gray card is better. One used to be able to use a Pringle's can lid back when they were white and not clear like they are now. :( Another alternative, the one I use most often, is one of the cheap lens cap white balance tools found on Ebay, they are like ~$8 US shipped and work very well!

For metering choose spot metering. And if shooting on a white background make sure to over expose by .5-1.0(easiest to use your EV settings to do this). If shooting on a black or dark background, then you need to under expose by .5-1.0(-.5 to -1.0), again, easiest by using your EV settings to achieve this.

Following these should greatly improve your color accuracy and decrease your editing time. :). Keeping in mind you are using full spectrum(or close to it) lighting. The 6500K Daylight spiral fluorescent bulbs work fantastic for this purpose.

But, if all else fails there are methods of correcting color in Adobe PS that work quite well even on JPEGs, they work so well color blind ppl can use them to achieve correct colors even though they can't see them! Same method I use to correct others' images for color.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 50 posts ]  Go to page 1, 2, 3, 4  Next

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock