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amguy
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Gem and Mineral Photography and it's Lighting
Feb 8th, 2011 at 9:21am
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I would like to cover as best I could the other half of photography: Lighting.  The only reason photography and shooting gems and minerals is possible is light.
In my opinion 30% of taking a good photo is all camera and the other 70% is lighting.  Lighting is very very important if it's 70% of taking a good picture.  Lets start off with light itself.  Light is brightness that comes from an object such as the sun, a fire, a flashlight, or a lamp.  All light comes from atoms. Atoms that produce light have either gained energy by absorbing light from another source or by being struck by other particles. It is this 'extra energy' that causes an atom to give off light. The light being emitted is carrying off the extra energy. 

Now when discussion light and color we must explore waves as well.  Waves have high and low points, and the distance between one of those highs and lows and the next is called a wavelength. Just how long that wave is will determine the amount of energy that it has. For example, a long wave has a low amount of energy or low frequency, and a short wave has a high amount of energy or high frequency. What we see in a rainbow, then, are the wavelengths of the visible colors. You see, our sun emits its radiation in this visible range, which our eyes interpret as the colors of the rainbow. These colors are identified as the visible spectrum. Thery are red, orange, yellow, green, blue, indigo, and violet.
Light travels in the form of a wave. It is basically photons (pieces of energy or particles), and mostly moves as waves. White light, or the light from the sun or lamps, is made of colors, and colors are different types of light recognized by their own wavelengths.  The color of anything depends on the type of light sent to our eyes; light is necessary if we are to have any perception of color at all. An object is "colored" because of the light it reflects—all other colors are absorbed into that specific object. So then, an Sweet Home Rhodochrosite appears red because it reflects red light.  Let me also add before I move on, that three things can happen to light.  It can be reflected, absorbed, or transmitted.  I will get to that later if I remember(note to self remember Grin)

Now to lighting and photography now that we have an understanding of what light is.  When it comes to lighting they make a big difference it what you preceive or the camera preceives.  That is due to kelvin temperature.  Kelvin temperature, also called color temperature,  is very very important when shooting gemstones and minerals.  Here is the definition from wikipedia
"Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that of the light source. Color temperature is conventionally stated in the unit of absolute temperature, the kelvin, having the unit symbol K."

Color temperatures over 5,000K are called cool colors (blueish white), while lower color temperatures (2,700–3,000 K) are called warm colors (yellowish white through red).

This is were having the proper lighting comes into play.  The white balance on your camera should actually be called the "color correction".  It helps to change the color temperature in whatever light you might be using.  It's not as good as actually using proper lights but it's a simple and easy way to make those small adjustments to help show what you are seeing in real life.
Here is a color temperature chart to show what some common temperatures are.


Here is another one which will also give you an idea of what color temperature is.


So what does this all mean?  If you notice it has a color which corresponds with a temperature which corresponds with a type of light/lighting.  This plays a big role in shooting gemstones and minerals.  It determines what light you use and what background you use.  It also correlates with what color gemstones and mineral and what color background you are using.

The reason you see many photos on white or gray background is it gives purity of hue(color) to whatever gem or mineral you are shooting and white is generally good for high-contrast or high key shooting  If you choose to use a background with color the accepted idea is to use complementing colors which are opposite the color wheel from the color of the object you are shooting.  The only problem with using a colored background is it affects the sensors on your digital cameras.  So if you are shooting a red beryl crystal on a green or blue background, even though the camera sensor is directed onto the red of the red beryl crystal light bouncing off the green or blue background is coming into your camera sensor and messing up what the camera see as the red in the red beryl crystal.  This may not sound like that big a deal as the slight color variation is not huge but when dealing with gemstones even the smallest color change can be the difference between a good colored stone or an okay stone or $10 and $10,000 when showing or trying to sell a stone.  If you notice on many of Jeff Scovill and Joe Budds photos they will superimpose whatever gem or minerals they took a photo of onto a colored background rather than actually shooting the photograph on a colored background  The preferred background color for purtiy of color is white or gray.


Here is an example of what a colored background can do to a stone.  You can adjust the white balance but it will either take away from the stone/specimen color or the background color.  You can't have it both ways.  The sensor is picking up the stone(pakistan moonstone) color but the light reflecting off the blue background in skewering what the sensor sees.


True color of stone


Now to lights.
There are 3 main types of lights which we all know and use.  Sunlight, fluorescent, and incadescent.  There are many what I call minor type lights including tungsten, halogen, high pressure sodium, metal halide, mercury vapor, xenon, LED, etc. but we will just stick primarily to the main 3.  Standard fluroescent lights typically have a bluer component to them and incadescents more of a yellow component and sunlight at noon in summer having a perfect blending of all colors(white light).  Sunlight at different latitudes, at different times of day, and how clear the sky is depends on which direction the color in sunlight leans towards.  Shade from a partly cloudy sky will leanb more towards blue and early morning or evening sunlight will lean more towards yellow and red.


What does all of this mean to us?  It means when we shoot minerals or gemstones of a certian color we want to use the proper light to help show an accurate picture and/or add some vibrance to the gem or mineral.  I will disregard sunlight since it can be finicky and not listen to our pleas and moans also it can be damn cold outside which neagtes my lazy butt from shooting anything out doors.  If you are shooting a tanzanite crystal what type of lighting would you want to use?  You would want one that leans more towards the blue end of the spectrum.  That would be a fluorescent light(partly cloudy day). Not all fluorescents lean towards the blue end of the spectrum.  Schools and hospitals are closer to 5500K above and below, most retail stones 4100K, and offices anywhere from 3500K to 6500K.   If we were shooting a heliodore what type of lighting would we want to use?  Incadescent?  Nope.  The reason being..if your perfect light is sunlight at noon on a summer day which equals 5500K(kelvin) then incadescent is way to far below on the color temperature chart from the "perfect" light at 5500K.  Incadescent being on average 2600K-2800K.  That is 2700K-2500K below what the "perfect light is.  The fluorescent light, which we used for the tanzanite crystal, averages 6500K(also called daylight bulbs).  Thats only 1000K difference from the "perfect" light(sunlight).  This is the reason why you never use incadescent light to shoot gems or minerals, which most of you already know.  What would I want to use to shoot my helidore crystal then?  I would prefer someting close to perfect but maybe with a little yellow added in naturally.  That means anything below 5500K starts to add some yellow and red to my specimen.  The more I go down in Kelvin(color temperature) the more reds and yellows I add.  You don't want to go so far as to skewer the accurate color of the specimen you are shooting but you want to add a little more color to it.  Now you might say "This will not give an accurate color to the person looking at the photo"!  It all depends on how it's viewed in real life.  If I take the photo under fluorescent light then take the gemstone to John Doe's house and he looks at it under the lamp in the family room it will be a different color than the one in the photo.  If I take a picture of a gemstone under sunlight then bring it to an office, school, or Wal-mart it will look different under the fluorescent lights they have than it did in the picture.  Here is a picture showing a 3500K fluorescent(left) and a 6500K fluorescent(right).  You can see the huge difference between the two and you can understand how each one will affect the color of the gemstone or mineral you are shooting.


My blue, purple, and green specimens and gemstones I like to use my Ott 6500K fluorescent lamps.  When I shoot yellow, red, or orange specimens I like to use my Solux 4700K bulb.  The Solux light is a halogen(3000K) but it has a special filiment and reflector which brings it to the 4700K mark.  Solux light are the creme de la' creme of lighting.  They are the same lights you see in highend dealers booth in Tuscon and at most gem shows and at the Smithsonian .  Here is the snippet from Solux:

        "The SoLux daylight lamp is universally recognized as the ultimate in D50 daylight simulation. Independent studies have concluded no other man made light source comes close (see volume 3, March 1999, Journal of Prepress & Printing Technology, Quantifying illuminant Metamerism of D50 simulators).  Recommended and specified by art museums, galleries, world renowned photographers, Fortune 500 companies like Dupont and BASF."

I have 2 Ott light for taking photos and 1 solux lamp,some tungsten bulbs, different halogens, photo bulbs, and a little of everything in between.  My basic setup I use my 2 Ott lights and my solux.  All others I only pull out for specific reasons or specific gems and minerals.  This shows my basic setup of lights and pods.


When it comes to light tents I have 4 of them, well actually 3 and a half.  Two of them are real light tents I bought and one I made and the 1/2 one I made and use for taking photos of only gemstones.  I find light tents useless and not worth a darn.  I used them a few times and realized they really added nothing.  I also know of no dealers or gem sellers that use them.  Most will have at least one but they don't use them.  A waste of money in my book.  The only way to properly shoot gemstones is to use a light tent but it is not your standard light tent like we all think about.  Hopefully I will get to that at a later time.

Here are some examples of different lighting and stones but first let me talk about color shift real quick.
Most of you have heard of color change or color shift gemstones.  You see them being sold all over the place.  Color change gemstones are just that...color changers.  They change color or flip across the color wheel.  If a color change moves from lets say Red to the next color on the wheel (orange) then this is called a Color Shift. If the color moves from Red to Green, which is on the other side of the wheel, then this is called Color Change.  All gemstones and minerals color shift to some degree.  Some do shift more promounced than others but all do to some degree anyways.

Okay first...this tanzanite crystal.  Same axis... same crystal....different lighting.

Fluorescent(6500K)


Incadescent


You can see the huge change in color just from using the different type of lighting.

Here is a paraiba crystal.
Note the rich vibrant blue under 6500K fluorescent


Now I use the 4700K  bulb.  Much less blue..not to bad but nothing like the 6500K bulb.


Now for incadescent(75watt 2700K).  Horrible.  Almost no good blue showing.


Here is another example of a blue and purple bi-color cuprian crystal
2700K


4700K


6500K


I used blue specimens to show the huge difference.  This is because blue is a primary color.  Now lets look at green, which is mixture of yellow and blue.  Since green is not a primary it's color shift in different types of lighting is less pronounced.  Take this peridot for instance

Incadescent 2700k


4700K


fluorescent 6500K


Not much of a difference between the three especially the 2700 and the 4700.  The 6500K to me looks a little better since it helps take more of the yellow out and adds blue which makes for a richer green.  The 2700 and 4700 and adding some yellow to the stone and since green is made of yellow and blue it's now trending more towards the yellow side which is an undesirable trait when looking for purity of color and in the case of peridot that would be green.

Lets now look at a stone which is in the red/orange/yellow side of the color spectrum.  This pre-formed spessartine garnet is orange as well all know.  Lets look at it under fluorescent light first(6500K)


Notice how brown it looks.  That is because when you add blue(fluorescent 6500K) to red/yellow(orange) you will get brown.  That is why the stone appears brown in the photo.

Now lets see it with more of a yellow added by using the 4700K and the 2700K incadescent.

4700K


2700K


Note how much better an orange it has.  The 4700K adds some yellow but the2700K adds a lot of yellow and it even adds orange since orange starts around 2800K on the temperature chart.  The incadescent picture has the littlest amount of brown since incadescent has less blue in it's lights wavelength.

I have many more examples of pictures in my recycle bin on the computer from when I used to sell.  When I would sell sphene, rubellite, almandine and namanga garnets, spessartine, and my yellow tourmalines from kenya, etc. I would use my Solux 4700K to take photos with but when I sold my blue and green tourmalines, tanzanites, hauyne, paraiba, etc. I would use my two Ott lights.

I didn't get a chance to add anything about setup or light positioning and a few other things.  Feel free RockhoundLounge members to add or correct anything you see.  I would like contributers so this thread can be a goo dreference tool for future use.


  
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JoeM
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Re: Gem and Mineral Photography and it's Lighting
Reply #1 - Feb 8th, 2011 at 9:26pm
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Wow! Thank you very much, AG.
You explained "color temperature" and the difference between
light sources so that I can even grasp it!
The difference in the tanzanite example is incredible!
Great introduction to what I hope will continue to be a very
enlightening thread.

Joe
  
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Scott LaBorde
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Re: Gem and Mineral Photography and it's Lighting
Reply #2 - Feb 8th, 2011 at 10:40pm
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Amguy, this information will be much help for those interested in improving their lighting set-up.  Well done and thanks!
  

Scott LaBorde
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Re: Gem and Mineral Photography and it's Lighting
Reply #3 - Feb 17th, 2012 at 6:43pm
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Amguy,  this article lured me to this website.  I learned a few things about lighting/bulbs and what background colors do to the specimen colors.  Thanks for posting this.http://www.rockhoundlounge.com/yabbfiles/Templates/Forum/default/smiley.gif
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #4 - Feb 17th, 2012 at 6:45pm
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Hmmm, how do I get one of your emoticons to appear?  I clicked on one, and its formula showed up, not the emoticon.  Thanks.
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #5 - Feb 17th, 2012 at 7:57pm
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Patricia, Only the formula will show while you are typing
your reply. Once you post it the emoticon should be there
in all its' glory.  Smiley

AG, just want to thank you again for posting this thread.
You did a fantastic job!
Joe
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #6 - Feb 17th, 2012 at 8:14pm
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Joe, do I need to click on anything other than the emoticon?  That is all I clicked before.  Will try again.  Here goes:   Smileyhttp://www.rockhoundlounge.com/yabbfiles/Templates/Forum/default/huh.gif
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #7 - Feb 17th, 2012 at 10:01pm
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Well, that's half the battle, Patricia.
Why it's posting all the other stuff too is curious.
Have to get the Computer Doctor Scott to take a look. Huh Smiley
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #8 - Feb 21st, 2012 at 12:47am
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Trying again for the emoticons.  Going to click on a handful.
Smiley Cheesy Grin Roll Eyes Shocked
  
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Re: Gem and Mineral Photography and it's Lighting
Reply #9 - Feb 21st, 2012 at 1:51am
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Joe and Scott,
Thanks! Cool
  
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