Digital Photography: Light and Temperature


Digital Photography MeSFRailyard 

Well. summer’s almost drawn to a close and fall is creeping up on us rapidly.  It seems like the perfect time to talk about the temperature.  Not the ambient temperature where you are, but the temperature of your colors…  Even the temperature of light.

Light is measured in degrees Kelvin and is based on a black-body standard.  Imagine a piece of iron laying on a forge.  The flames are kicking and the black iron bar begins to heat up.  As the iron heats initially, it glows a bright red.  The hotter the iron gets, it begins to glow orange, then it gets yellow.  Eventually, that yellow transforms into a burning white hot color, and the it turns blue.  This is how color is rated in photography.

What’s that have to do with my pictures, you ask?  Well, let me ask you a question.  Have you ever been flipping through the dials on your camera and saw some funny numbers like 5000K, 3200K, or 6500K?  If you answered yes, then you have discovered how to change the white balance setting on your camera.

Modern camera sensors do a fairly decent job of detecting and isolating light based on the color of the natural light filling an image, (the ambient light).  But, different light burns at different temperatures.  If you set the white balance in camera, then you’ll have less work to do when it comes to adjusting your image later.

Have you ever seen a picture taken under fluorescent lights?  Sometimes they come out a sickly green color.  A flash taken in a dark environment?  The light is a white to bluish color.  Why?  Because of the color temperature of the light in the image.

If you take a picture inside and find you don’t like the color cast or hue of the overall image that you’ve taken.  Get a little creative.  Experiment with the white balance settings on your camera.  Notice the changes that are made when you select different types of automatic adjustments.  Like the cloudy day white balance settings…  Notice how it warms up the image with a nice soft yellow touch?  It is trying to compensate for the amount of blue in the image by adding yellow to your picture.  Tungsten, notice how it turns everything in the image to a seriously deep shade of blue?  It is adding blue to the picture to try and balance out the amount of yellow coming from the tungsten lights.  Experiment for effect, and eventually, you’ll learn, if your camera is capable, how to dial in a custom color temperature setting to appropriately depict the environment you’re trying to capture in an image.

Just some gee whiz numbers to chew on…  The afternoon sun at 12 noon on a summer day is 5500 degrees Kelvin (5500K).  The yellow/orange glow given off by Tungsten lightbulbs?  About 3200-3500K.  Shade from a blue sky?  About 6500K.  An absolute rich blue sky?  About 10,000K.  (Notice, contrary to popular belief, blue is actually a hotter color than red or yellow, don’t get this confused.  It is not blue as in cold, but blue hot, which is a flame of an entirely different color.)  Have you ever heard of the golden hour?  This is when outdoor photographers like to get out and take most of their pictures.  The first hour after sunrise, and the last hour before sunset, the sky is a nice soft shade of orange/yellow, ideal for capturing the brilliant colors of the natural environment (3500K).

So, what does all of this mean?  When your camera takes a picture, it is trying to decide which is the right shade of white to apply to the image.  It is trying to decode and adjust your picture based on what it thinks should be white.  It is trying to pick an appropriate white balance setting. 

So, if you’re trying to figure out why your camera is making your pictures look funny with different colors when you take a picture indoors, it’s because of the camera’s white balance settings.  Figure out how to tweak these and you’ll be one step closer to making better pictures.

And now for something completely different…

I usually don’t do product plugs on my blog, but these two are definitely worth the time and the webspace.  Steve Krenz, author of the Learn & Master Guitar DVD Series has just released an email announcing the final release of a product I have waited for for over three years, since I first heard of it’s inception.  The product?  A video game called Guitar Apprentice, similar in style to the popular video game series Guitar Hero for all of the major video game consoles and systems.  The difference?  Guitar Apprentice is an accompaniment video track that allows you to play along on a real guitar!

Guitar Apprentice

The point should be made, this is not a true video game, as you do not have feedback coming from the game as you are playing.  You use a much more sensitive device for that feedback, your own ears.  The game will not teach you to read music, but it does allow for a new and creative way to improve muscle memory as you practice.  This week Gibson is offering the Beatle’s song “Get Back” for free.  More songs are available through their catalog.  I’ll be interested to see if this idea takes off.  I’ve been waiting a long time to see how it would play out.
I haven’t been this amped about the useful side of video games since the Phillip’s CD-Interactive released the Kodak sponsored video game system on 35mm Photography.


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  1. Thanks for the explanation and how you can fiddle with your camera settings to obtain different results .

  2. You will forgive me for being a bit smug every time I hear someone back in the States talk about how summer is nearly over and how Fall is just around the corner…and then of course how WINTER is next!!! Because I now have endless SUMMER! Oh sorry….I get a little carried was such a bad winter last winter…yes, it IS nice to know how to adjust the light…your way is much easier than moving to another country….
    Sonya Lenzo

  3. Kevin Bettencourt

    This article was filled with specifics That I had to read a couple of times over and I think I’ve got it.
    As far as Guitar Apprentice, I checked it out and after playing and teaching guitar for almost 20 years, this is the best innovation to learn how to play guitar I’ve ever seen.

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  4. Clare Delaney

    I had learnt about white balace on an ‘intro to digital photography’ course, but they didn’t explain it as well as you do. Thanks Dewayne!

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  5. dewayne, yor explaination of light and how it works in pictures is fantastic. Thanks for sharing more expert photography advice.
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  6. I never heard of Kelvin degrees or knew about the white balancing settings and so many other things…!

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