Sometimes taking a neutral position on things isn’t really the safe thing to do – sometimes it’s actually downright destructive!
Your camera’s AWB, or Auto White Balance is a typical fallback lighting selection used by most of us because we assume that the camera is smarter than we are, or at least more capable of judging lighting conditions when in a hurry. But assuming that AWB will diagnose lighting and set the proper color temperature could be dangerous. Here’s why.
The first thing to understand is that in the language of RGB color, equal values of red, green, and blue (like red 128, green 128, and blue 128) produce an absolutely neutral gray color. The AWB algorithm in your camera always assumes that there is a detectable neutral gray component in the scene. It then examines the light reflecting from objects in the scene and locks onto the cluster of pixels whose values are closest to equal (regardless of how dissimilar). The AWB mandate then forces those colors to become absolutely neutral value.
This is all well and good IF that cluster of pixels actually is suppose to be neutral in color. The corrected values will then actually improve the balance of color in the image. But, if the scene doesn’t have any neutral component; if there is a bluish-somwhat-gray item in the scene but no actual gray item like the snow scene below, the image processor in your camera will dutifully change that bluish color to neutral gray, and shift all the other colors in the scene at the same time!
Your camera is not smart, it is just efficient and obedient. It will obey anything you tell it to do. It’s a machine, it is not a volitional entity. It will never be “intelligent” in the way that humans are intelligent. It can be programmed to follow a logical sequence, but it cannot “make decisions.” In the snow scene example, you would have given it a command to shift all colors, and it would have obeyed your command and produced bad color; all in the name of Auto White Balance. Hmmm. Don’t be stupid. You’re camera is stupid. You are the intelligent one. You must tell it what to do- NOT the other way around. Hrrumph!
In the same way, there is a time to use your 18% gray card, DataColor SpyderCube or ColorChecker Passport to reference true neutral gray in a scene and set the gray balance in your photos, and there is a time to keep those items in your camera bag. Truth is, neutralizing every image can suck the natural color right out of the scene.
As most of you already know, one of these gray balance tools placed in the photo scene (for an initial test shot) means that it can serve as the gray balance reference for correcting any color shifts in the image. This correction takes place after the capture; when the image is opened in Adobe Lightroom, Camera Raw or Photoshop. This is truly a great way to accurately set the gray balance within a series of photos taken during a single session. In raw interpreter software, all photos can be opened (including the test shot). When the White Balance tool is applied to the reference gray in the test image, all photos open at the time can be color corrected automatically. Great idea! Right?
Yes, unless… the scene contains “emotional” light- candle light, sunrise/sunset, late afternoon or early morning light, nightlife/neon, etc. If the scene to be captured contains this kind of emotional (or mood) lighting, that very mood that made you to capture the image to begin with can be neutered by White Balance.
Late afternoon Florida sun presented a very warm and rich lighting to this shot. I used the Neutral Balance eyedropper in the editing process, choosing the most neutral colored surface I could find to set the White Balance. As a result, I completely destroyed the warmth that attracted me to capture the image in the first place.
This shot was taken in Fairbanks Alaska on December 28th at 10PM, and captured the surreal lighting that occurs up there at this time of year. The cool shadows that are evident in the foreground are typical of moonlight reflecting off the snow. Setting the camera’s color mode to Daylight, allowing the tungsten lamplight to show warm lighting amidst the cold snow captured exactly what I saw. On the right, the camera’s white balance was set to AWB, assuming that this “automatic” setting would capture the colors of the image faithfully. Oops! AWB actually lost the shivering cold lighting altogether.
In both of the above cases, when white/neutral balance routines were employed, all the ambiance of both scenes was dutifully destroyed. By forcing each unique lighting to be neutralized, both the warmth of the Sun and the frigid look of the night snow were lost.
There is no single, always-right color balance setting on a camera. In fairness, most times, the AWB setting in the camera and gray balance in the editing stage work out very nicely. But occasionally the stupid camera and the powerful editing software needs smarter input. From you.
So what have we learned? There is a time for white-balance just as there is a time for political correctness, BUT to force the strict application of either in every situation can destroy the spirit of free expression. Use gray balance only when emotional/mood lighting isn’t the setting the scene and a gray component is. Too many dramatic scenes get neutered in the name of neutral balance. Protect innocent pixels.
This series is a small excerpt from my soon to be released book titled The Digital Image: From Capture to Presentation and Everywhere In-between. If you find this series helpful, imagine what the book will do for you.
That’s the way eye sees it. Feel free to leave a comment and keep the conversation going. Thanks for joining me this time. If you learned a little something, let me know and tell your friends. Sign up now to have these posts automatically sent to your email address (top right of this page).
See you next time, Herb
PS. if you have an iPad and are interested in learning about more about the fundamentals of color, light, and digital photography, I suggest that you take a look at my Accurate Color iBook in the iTunes Store