Problems with color shift (White Balance) on Nikon D800

Started Jan 19, 2013 | Discussions thread
Luke Kaven
Veteran MemberPosts: 5,195
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Re: Problems with color shift (White Balance) on Nikon D800
In reply to ronste, Jan 19, 2013

ronste wrote:

[...]Maybe if I had use the "Auto" White Balance would I not have seen this problem,

The conclusion must be that the arena light where I shoot change rapidly all the time (as you explain), and you cannot use a preset white balance for this type of location.
Because of this is it necessarily to use RAW.
Since this was my first shoot in arena light with the D800 I was surprised when I saw the first picture. I was afraid that the problem was D800, but the problem seems to be me that never had heard of the change of color temperature in an arena.
So today I have learned something new.

With some lights, such as florescent lights or sodium lights, due to the physics of how the light is produced, the resulting color temperature is a complex function of many different kinds of materials in a variety of different states.

With these complex lights, you do not get a simple "Kelvin" spectrum, derived from the spectral characteristics of simple matter called "black bodies".  The Sun is basically a black body radiator at 5750K and with a smooth curve, it can be color balanced to give a full spectrum using a linear function.  But these newer lights, most of them, cannot be white balanced at all.

Compare the color spectrum of an incandescent lamp with a florescent lamp in the image linked below.  Note the huge spikes added by the mercury.  One of those spikes is green, ghastly green.  Creating a white balance for this is hard.  You need a full color profile (e.g., QPcard) to get anything even approximate, and it will never be right.

http://upload.wikimedia.org/wikipedia/commons/b/b0/Spectral_Power_Distributions.png

When you buy bulbs from now on for photography, you are interested in what is called the CRI, or Color Rendering Index.  CRI = 100 is the sun.  You want CRI >= 93.  Most consumer bulbs are much much worse.

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