Nature is full of colors. However, color is not an invariable property of an object. The color of something will change depending on a variety of factors, including the wavelengths of light striking the object, the absorption and reflection of those wavelengths by the object, and finally, our own eyes. In this article, I’ll show you how colors can vary with one subject in particular – hummingbirds – and how I approach photography with structural colors in mind.
First of all, I have a simple question for you: how does color perception occur? Well, simple can be misleading. Color is a complex phenomenon. But it starts with a source of light like the sun.
Every moment, the Sun emits photons that have to travel about 150 million kilometers in the vacuum of space before they finally reach Earth. After about eight minutes, they collide with objects around us. Depending on the nature of the object’s surface, some photons are reflected, and the rest are absorbed. With 6 million receptors in the retina of our eyes, we pick up these reflected photons, and our brain translates them into objects – shapes, sizes and colors.
Take even the most colorful hummingbird into a dark room, and its color will fade like leaves in autumn. Where there is no light, there is no color. But let’s bring the hummingbird back into the daylight.
Our eyes can only catch a narrow slice of electromagnetic waves ranging from about 380 to 700 nm. These different waves appear as colors to our eyes. There is violet at one end (about 380–450 nm) and red at the other end (about 610–700 nm). In between are blue, green, yellow and orange – while most interestingly, magenta stands as a combination of red and blue wavelengths, and does not have its own wavelength of light.
You may not be surprised to learn that many animals, such as birds and some insects, can see a much wider range of colors than we can. But other people may envy our color perception. Horses can only see a combination of yellow and blue, while the humble mantis shrimp can see both UV and IR light without breaking a sweat.
On the other side of this discussion is the light that animals reflect. Have you heard of the green plant pigment, chlorophyll? Or the pigment melanin which affects our skin color as humans? There are only two of the many colors on the tree of life. Animals have carotenoids, lipochromes, porphyrins and other pigments that give them unique colors. These pigments aren’t just for show – they may be essential for survival. Among other benefits, pigmentation helps an animal disguise itself, attract a mate, or warn potential predators about danger.
However, pigmentation is not the only way a living thing can change its color. The surface of the animal also has a structure – which structural color – And this is my reason for writing this article. The surface structures of many animals, including hummingbirds, can act as sophisticated (and microscopic) mirrors. If you zoom in enough on a hummingbird’s wing or a beetle’s shell, you’ll see an intricate maze of microscopic pores that give the animal its structural color. Butterflies, peacocks, ducks and many others have similar types of characteristics.
If you want to study these delicate structures, a normal microscope won’t help. After all, light-absorbing pores are only a few hundred nanometers across, so you’ll need a scanning electron microscope that can produce magnifications of more than 1,000 times. I don’t have such a microscope, but science photographer Petr Jan Juracka does. Here You can see his unique pictures of butterfly wings and read some interesting things about them.
Unlike pigments, which typically deteriorate quickly over time, structural colors can last for ages. Fossils of long-extinct beetles have been found there that still retain their original color.
Let me return to the mirror analogy. Structures on the surface of an animal, due to their spatial arrangement, are able to reflect colors in the desired direction. It is like reflecting a beam of light from a mirror into someone’s eye. A slight change in angle, and the light (or color in this case) gets deflected elsewhere. Some birds, such as hummingbirds and birds-of-paradise, also use this effect to communicate.
That’s right, birds don’t have feathers just for flying or to protect themselves from harsh environments. Feather color also plays an important role in camouflage, reproduction, and defending the territory from unwanted visitors. Consider brown violets. By spreading their colorful “ears” and adopting an expressive posture, they can send a clear message that the intruder is not welcome.
Finally, let’s look at pigment and structural colors from a photographer’s perspective. With structural colors, the direction of light plays a big role, and if animals simply turn their heads, or the lighting changes slightly, their appearance can change significantly. Pigment colors, on the other hand, are much more predictable. The yellow color of the tanager (a pigment color) will be yellow from all angles, and will remain yellow even if I use artificial flash on it.
And here I come back to the title of this article, “Compositional Color: The Art of Photographing Hummingbirds.” In the pair of photos below, I want to show you what your hummingbird photos will look like if you use a flash attached to your camera. (Let’s ignore the other effects of the flash on the scene you’re photographing and focus only on the hummingbird.)
Note that the color of a bird with flash is very different from natural light. In particular, the green color of the feathers fades to bronze under the influence of flash. Many colors are completely lost. This is because suddenly, several microscopic mirrors are directed in the direction of your camera, making the bird jump unnaturally from its surroundings.
So, what to do when photographing hummingbirds or other animals with structural colors? Look for diffused light and don’t be afraid to increase the ISO. Or, if you use a flash to photograph a hummingbird, do so with a large diffuser – and use multiple off-camera flashes if possible.
In my opinion, hummingbird photographs come out best in diffused sunlight. Of course, it’s possible to photograph them in direct sunlight or with a flash and still get good results. But if you’re not careful, harsh lighting can hide these beautiful structural colors.
