For all the incredible technology packed into cameras, there is one missing element that will remain missing perhaps forever. The missing element? The combination of human eyesight and the brain’s image processor called the Visual Cortex.
The Visual Cortex
The Visual Cortex is located in the lower rear of your brain. It is here the real color perception magic happens – magic that goes way beyond the analysis capabilities of any camera on the planet. As you understand this human version of the camera’s image processor, your understanding of the photo process will come into clearer focus.
Medical experts tell us that more than 80% of what we experience enters our brain through our vision. Your eyes capture light’s amazing array of colors as the eye’s lens focuses light beams onto the panoramic viewing screen in the back of your eyeball called the retina.
Your brain is very forgiving. It focuses light entering through your eyes, and automatically color corrects almost every lighting condition and color cast en route to the Visual Cortex. Within seconds, your eyes and brain adjust to a wide range of lighting intensities and color influences and deliver very believable images to your mind. And it all happens without you even realizing it. No white balance to set, no color shifts to neutralize. Your brain’s magic intuition and forgiving nature do a crazy-good job of color correction for you.
Your camera records colors a bit more objectively. However, even when shooting RAW files, decisions about color still have to be made in the editing process. Your camera simply doesn’t have cognitive or reasoning skills and thus must be tutored to interpret what it “sees” accurately. You might say that your camera sees, but it doesn’t observe.
White balance and memory colors
When you visually observe a white sheet of paper in a daylight lighting (preferably outside, in natural light), the paper looks… white. Even when you observe that same white paper indoors under tungsten light, your brain recognizes that the paper is really white. This is because the human brain possesses what we call “memory colors;” a basic set of colors that are so familiar that even lighting variances cannot confuse.
Your camera cannot remember what color white is when it is captured under different types of lighting. It must be told every time. What your camera calls “memory” isn’t the same “memory” that your human brain possesses.
When you set your camera’s White Balance to Daylight and take a picture of the white paper outside, it indeed appears white. That is merely the way the camera’s image sensor is biased to record light under daylight (6500° Kelvin) color conditions. However, when you move inside and shoot the same white paper under tungsten lighting (using the same Daylight WB), the paper appears to the camera to be somewhat yellow.
Changing the camera’s WB setting to Auto White Balance (AWB) and shooting the paper under a typical table lamp light, the picture still appears slightly yellow. Even when you set the camera’s WB to Tungsten, the paper still fails to appear perfectly neutral white, though it appears much closer to white.
The truth is, there are colors in the visual spectrum that digital cameras record differently than film cameras did in the past. And neither technology captures and records the exact colors that the human eye sees or the mind perceives. This is why most captured images, for all their beauty, still lack the full sense of authenticity and depth that the human mind experiences from light observed in every scene.
Technically (and spectrally), in each case, the camera is telling the truth, just not the “truth” that we perceive with our eyes. This is, of course, a good example of why we shoot in raw format. When captured in raw format, all regimented color categories get ignored. Any color shifts can be corrected and lighting variances addressed in the post-processing stage.
As mentioned earlier, the can’t the camera see the white paper as white (the way our eyes do) regardless of the lighting situation because the camera doesn’t have an onboard reference registry of “memory colors” the way our brains do.
The brain automatically remaps each scene’s color cast to your brain’s “memory colors.” Think of these memory colors as preference presets in your brain’s color interpreter. These memory colors automatically compensate for variable lighting situations. The infinite Look Up Table (LUT) variables that would be needed for a camera to replicate this basic, natural brain function would have to be both immense and incredibly complex. No matter how smart digital devices become, they’ll never replace the magic of human interpretation.
So what have we learned? Your camera, for all its sophistication, cannot automatically correct color casts. It simply isn’t human. That means that your camera ultimately benefits from and makes use of your understanding of the behavior of light and color. Armed with this knowledge, you’ll produce images that more closely replicate color as your mind perceived it. Photography is a two-part process that requires the camera to do its job and for you to do yours. What is defined by the clinical term as “post-processing” is merely finishing the job that your camera started.
Moreover, this is a good thing. Your judgment and interpretation of the colors your mind saw when you captured the image can guide you as you tweak and make minor adjustments to your images. Don’t think of this as a burden. Recognize this as a gift. You, the photographer, are the producer of the image. Your camera is merely a tool that provides all the “raw” materials you’ll need to share what your mind observed when you captured the scene.
This is why photography is an art, and why this art requires an artist. You are that artist.
Celebrate the partnership you have with your camera. Together, you produce visual beauty.