The setting in the image capture and editing processes known as White Balance is a curious one indeed. The human light perception system is so complex, and so intuitive, that we don’t totally understand how it even works. All human color correction happens so automatically that we sometimes don’t appreciate how worry-free it really is.
As photographers this natural phenomenon becomes more apparent when we deal with the limitations of our cameras to capture and sort out the variety of lighting conditions that occur constantly. Our cameras cannot deal with nature’s lighting changes subjectively, and intuitively like our minds can. This is because camera image processors are machines, and they can only record light objectively. And the white balance controls in both our cameras and our editing software are built purely upon broad assumptions. Therein lies the problem. We assume that our cameras can see light the same intuitive fashion that our eyes do. But that’s a bad assumption.
Your eyes adapt to color temperature changes constantly. To prove this just put on sunglasses that have a slight color tint. While this tint is noticeable for a moment, in just a few seconds the color processor in your visual cortex will recalibrate the scene and completely eliminate the color cast. Any object that your mind recognizes as typically white will appear white even if the color of the light reflecting from it has a color cast.
This is because your eyes and your brain enjoy what we call Memory Colors. Memory Colors are colors that you have seen so often that they are registered in your brain in some form of human reference system. Even if the lighting on an object is less than optimal, your memory colors automatically remove the color cast in your mind.
When the camera sees a color cast it records that color cast quite objectively. Golden hour photographs exhibit a warm cast and as long as our camera’s white balance is set to Daylight, that warm color cast will seem natural. But at the same time, Daylight WB photographs shot in overcast situations will exhibit a slight blue cast that will appear cool and unnatural. To record colors that appear natural, we must set the camera’s WB to Cloudy, which tunes out the bluish cast. If images are captured in the shadow under overcast lighting, the appearance will be even more blue unless we set the WB to Shade. Now that ain’t natural!
Thank you Lord for the gifts of Memory Colors and true Auto White Balance. Remember, you gotta be smart because your camera is capable, but it really isn’t smart! Coming soon: The GottaKnow Video Series. The online video series that will make you bright about light and color savvy. Get Smart. Your camera is depending on it.
That’s the way eye sees it. Feel free to leave a comment and keep the conversation going. If you saw this post listed on a LI group page, add a comment to the listing in that group! Thanks for joining me. If you like this blog, let me know and tell your friends.
See you next time, Herb
PS. if you have an iPad and are interested in learning about more about the fundamentals of digital photography, I suggest that you take a look at my Accurate Color iBook in the iTunes Store