What Exactly is Accurate Color?
Cameras don't see color the way we do. Being much more sensitive to the color of light, it can be all too easy to end up with images possessed with an unwelcome hue. You can adjust the white balance correct color, but what exactly is accurate color?
It seems obvious enough. Something is red. Something else is blue. The color of a third thing is somewhere in between. Anyone who ever spent an afternoon exploring a box of crayons while growing up will be familiar enough with the concept.
Objects get their color by reflecting certain wavelengths of light and absorbing others. An object looks red reflects red light, absorbing the rest of the spectrum. Ditto with the other colors in that box of crayons. A white object reflects all wavelengths. A black one absorbs all wavelengths, which explains why a dark colored car gets so hot when you leave it in a parking lot for a few hours.
But I digress — back to photography.
You get up early to capture some amazing images at sunrise, or sit admiring a scenic vista late in the afternoon, camera at the ready, waiting to augment it with the golden hour light of sunset. You want your images to come out perfectly so you carefully adjust the white balance before the action starts. Perhaps you even use a gray card because you're serious about getting accurate color. But regardless, when you look at the resulting images, your white balance adjustment has magically compensated for warm tones of the sun leaving you with images that could have been shot most any time. What went wrong?
To answer that question, we need to revisit the topic of how objects get their color. Those certain wavelengths I mentioned that get absorbed or reflected come from the light shining on an object. If you shoot when the light is a warm, radiant hue, objects will look different than they will under the cool blue light of a cloudy day. The purpose of the white balance adjustment on your camera is to make objects look reasonably the same under both extremes. But just because you can do this, why would you want to?
What actually is "accurate color?" Is it the color of the object you are photographing, or the color of the light shining on it. The two interact with each other to yield the final result of what you see or what your camera sees. If you're a portrait photographer you likely want skin tones to come out correct in any light. As a nature photographer, I want the golden color of sunrise or sunset to show reflecting off what I am shooting. That's why I'm there at that hour after all. As I wrote recently, it's the lighting that makes the photograph.
Here's something else worth thinking about: since a camera sees color temperature differently than you do, and different camera sensors and different films (remember film?) record color differently, is there really one single answer to what something should "look like" even if you decide you want the color of the light to influence the result? How much should it influence it? It would seem there is some leeway in this. Unless you go overboard, you can adjust the white balance at will to make an image look good. In this sense, accurate color becomes simply color that looks good.
When shooting raw, the camera white balance setting actually becomes somewhat irrelevant since you can adjust it after the fact on your computer. Even when using a raw converter that defaults to the white balance as shot, you can change it without degrading the image due to the nature of raw image formats. Because of this, the simplest approach is to leave the camera on auto white balance and forget about it. You can then adjust things as you want when developing your images in Lightroom. The camera setting does matter if you shoot jpeg since then the raw conversion happens in your camera rather than your computer. This fact is a good reason for shooting raw when the lighting conditions are changing rapidly but if you nail the exposure and white balance in the field, jpeg can be easier.
Either way, you get to decide how you want the colors to look.