What Color is That Tail You're Chasing?
As should be obvious, a big part of color photography is the color. So why is it so difficult to get the colors to come out right?
It would be nice if there were a straightforward answer to this problem. It's always nice to have a silver bullet — some magic remedy that will solve everything. Such hopes typically remain unfulfilled, and this time is no different. When you get down to it, color is more complicated than it seems.
Artists visualize color using a wheel with the various hues arranged around the circumference. For today's trivia tidbit, it was none other than Isaac Newton who invented the color wheel in 1666. He had seen that the sequence of colors in the rainbow was always the same. And like Newton always did, his mind wandered. Newton and his collaborator A.H. Munsell likened the sequence of colors in the spectrum to musical notes that always return to the same tone but an octave higher. Like notes, wherever you start on the color wheel, the sequence ranges through the spectrum to return to where you started. It's a testament to how clever that was that we all use color wheels to this day.
But as convenient as this may seem, it doesn't reflect reality. The colors in the rainbow do not repeat but represent but a small slice in the overall electromagnetic spectrum. Once you go past orange and red, you proceed into the infrared and radio waves. On the other side of indigo and violet, the frequencies continue into the ultraviolet and X-rays. It doesn't return to red. The spectrum is linear, not circular. If you're up for some more trivia, this explains why the color purple is so rare in nature. Something has to reflect both blue and red hues, frequencies on opposite ends of the visible spectrum, to produce that regal purple so prized over the centuries.
In reality, nearly everything reflects a combination of frequencies in various intensities. If you use a prism, you can separate sunlight into its components. But you're unlikely to find many real-world objects so pure. Just like with purple, it's the combination of frequencies that count. Something that reflects pure blue and pure yellow will appear to us as green, and so on. Even the simplest object contains multiple chemical elements. Put together some admixture of chemicals, and the combination determines what color we see.
And the plot thickens further. Things get their color based on the light they either reflect or emit. Very few objects are luminescent, so most have to rely on reflecting ambient light to be seen. And light sources have a color spectrum, too. That perfect spectrum projected by the midday sun will look different at sunset or twilight. If the source is artificial light, it will look even more different. The white balance control on a camera can help you compensate if you prefer daylight balance regardless of the light source. Sometimes, you want the added color. Advertisers add a splash of colored light to catch our attention. Some photographers have difficultly with sunset photos because they don't disable the auto-white balance on their camera. Unless you know how color temperature works, you're at the mercy of your camera defaults.
Even still, color can be problematic. Objects can only reflect the light that is falling on them. They, too, are at the mercy of color temperature. Something that primarily reflects green light will appear almost black when illuminated by light that is pure red. All it has to work with is red light, and it doesn't reflect any red.
Objects reflect various wavelengths and intensities across the frequency. And light sources have their spectrums, too. Put the two together, and you end up with a color problem known as metamerism. If two things appear the same color under one light source but different colors when the light is changed, that is metamerism. The people who make pigments for inkjet printer inks know all about metamerism. Devising better ways to solve the problem is something that keeps them up at night. A bit more trivia for you: the people who make paint for new car models love metamerism. It's how they create those iridescent paints that make cars look green sometimes and blue at others. These people are getting almost too good at metamerism and need to sleep more at night.
And color gets stranger still. In 2015, a social phenomenon spread across the internet as a photo of a dress. The attire wasn't scandalous, but its color was curiously hard to nail down. To some people, it appeared as white and gold, and to others as black and blue. Scientists are still arguing over the explanation. My money is that metamerism plays a big part, but apparently, it's more complicated than that. And you thought you had color problems.
As a photographer today, the problems with color are only just beginning when you press the shutter. It isn't just the light shining on your subject and what wavelengths it reflects that determine color. We can only see our photographic masterpieces on an LCD monitor or other medium. I wouldn't trust critical color decisions to the camera-back display, but thankfully I don't have to since I shoot in raw. But I'm dependent on the color accuracy of my desktop monitor when I later adjust color in Lightroom. A perfect monitor would be capable of displaying uniform and accurate gradients regardless of color. But while the gamut of monitors is improving, their accuracy is still far from perfect. If you want to see the color you shot, profile your monitor so your computer can compensate for any unevenness it may have. If you haven't done so yet, you can rid yourself of many color woes by profiling your monitor.
Technically, you can profile your printer to make sure it's accurate as well, but I generally don't recommend it. Those guys who get paid to make better printers and ink have a lot bigger budget for printer profiling than I do. You can rid yourself of another huge chunk of color woes by sticking with manufacturer combinations of paper and ink rather than mixing and matching based on price or advertising hype. Once you understand the color management controls in your printer's driver settings and can consistently get prints that match your profiled monitor, you can dabble in third-party papers. But make sure you download and use their ICC color profiles, or you'll be back chasing your tail trying to get good color.
There's one other point worth making here. To see the most accurate color possible, don't have the room lighting excessively bright. Editing with too dim light can be hard on your eyes, but doing so with too bright lighting can create problems for your monitor. That ambient room lighting is shining on your monitor display. There's no sense in creating undue competition with the light and colors emanating from your monitor. Likewise, don't go too crazy with the paint color on the walls. Like with that dress, human color-vision is easily led astray. I'm not about to do as some recommend and paint the walls medium-toned, neutral gray, but I wouldn't want to try optimizing images with wildly saturated wall paint either.
Ultimately, the color we see and react to is both physical and psychological. Not everyone will respond the same based on color. Don't believe me? If not, there would be little point in asking what someone's favorite color is. Variety is the spice of life. But not everything about color needs to remain such a mystery.