Color & White Balance Primer

Consider this to be background reading.  You can make images with good color without knowing everything mentioned here – if you read all of the other color sections. However, reading this primer will help you to understand why certain recommendations are made later.
For starters, here’s an excellent article on white balance from the site of Ron Bigelow.
Next, a little background on color and light – the color you see in your captured images originates with the light reflected by objects in your scene, and

  • The captured result is as “seen” and rendered by your camera’s sensor (which may not agree with what your eyes see)
    • Your camera must estimate or be told the temperature of the light (this is what white balance does)
    • In Auto-WB the camera makes a new estimate with every shot
      • and the light does change constantly, especially outdoors
      • and you may not want every image made at a given shoot to each have different colors
        • thus necessitating each image to require its own post-processing correction
        • rather than just fix one image and “copy” the same correction to every other image
      • Better to “give” the camera a fixed estimate, such as cloudy rather than have it continually “estimate” via Auto
        • “Give” a setting that is closest to the actual lighting
        • For example, don’t use tungsten outdoors
    • Poor temperature estimate = poor colors
  • The “real color” may or may not be the same as seen by your eyes
    • What the camera sees is usually closer to the “real” color (as determined by the laws of physics – enough said) than what your eyes see
    • The color that you think is there is just that, what you “think” –
      • It is what your brain and sensory system have adapted your visual senses to “think” is the actual color
      • It may not be the “real” color
      • The “real” color is affected by the temperature of the light
        • Tungsten bulbs (your ordinary bulb) have a warm orange-like tint. A piece of white paper reflects this orange color. Your camera sees the orange (unless you set WB to tungsten to compensate). BUT – You see white! Why? Because your brain is conditioned to show you white when it knows that the paper is white. Your brain compensates while the camera simply reports the “facts”.
      • For an amazing demo of your mind & eyes fooling you, check out this 5 minute video, Can you really trust your eyes? – especially the last 2 minutes
  • Ed, You often mention “neutral”. What is that?
    • Your camera captures three colors – Red, Green, & Blue (often called the RGB color model).
      • These three are combined to create every other color & tone produced in the camera’s final captured image.
      • Every final color is made up of from 0 to 255 parts of each of the three
        • 255,0, 0 is red;  255,255,0 is yellow; and so on for a total of 16,777,216 combinations
        • Go here & experiment on your own
    • Neutral is any color where the RGB components are all the same
      • 0,0,0 is black; 255,255,255 is white; 128,128,128 is middle gray; and so on for any of the 256 possible neutral values
      • If you need to fix colors in post processing the simplest and most accurate way requires a neutral reference
        • Which you can click on so your photo editing program can say – “Aha! There’s something neutral“.
        • Without a known neutral reference, all bets are off.
        • You don’t need a reference in each and every photo
          • just each and every one that’s in a different lighting situation
          • most programs will allow you to save the reference image’s correction for use in the rest of your photos
          • so the bride doesn’t always have to have a reference card in front of her face 😉

Continue to Color, Part 1

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