Infrared is literally a way to see the world in a different light. Many things look strikingly different. Here I will tell you enough about Infrared Photography to appreciate it. You may become interested enough to start taking your own Infrared Photos. I will help you get started with that too.
When I tell people I take Infrared photos, they often say “So, you are photographing heat.” No, that’s a misunderstanding.
There are special infrared cameras that do detect radiation from warm objects like people and vehicles. But infrared (IR) refers to a huge range of radiation; everything between red visible light and microwave radio waves. The infrared that people and warm objects give off is long wave IR. This kind of IR doesn’t go through glass! Not even glass in a lens. So to make an image requires exotic expensive equipment, and the pictures are blurry. However, we do have cheap thermal IR detectors that can open doors and turn on lights.
Near Infrared is the short wave IR that is just beyond visible red light in the spectrum. You can think of it as light of a color we can’t see. Since it is so much like visible light, ordinary lenses and cameras can be made to work with it, so we don’t need exotic equipment.
Back to the idea of heat. You know that if you get something hot enough it will give off visible light. Fire and old fashioned light bulb filaments, for example. At lower temperatures, but still very hot, things will glow in near-infrared. So I can photograph coals that no longer glow in a campfire and get a bright image.
Since we are not usually photographing such hot objects, we need a good source of infrared light to shine on our subjects. Like the sun. We live in a colorful world, meaning that things reflect different amounts of different colors of light.
Grass reflects green, but not much red or blue light. But it also reflects near infrared even better. This becomes obvious with the first infrared photo you take outdoors. If we could see infrared, we would call grass infrared, not green. The same is true of any green foliage.
A blue sky gives off practically no infrared, so it looks black. Clouds are great reflectors of all light, and look bright in infrared. Snow also. Snow and grass look practically the same in infrared. Since the blue sky is so dark, shadows look black in infrared, unless there are clouds to reflect some light.
You know how everything looks blue or hazy gray when you are high up on a mountain, tall building, or in an airplane? I love to look out airplane windows, but when I took photos everything was blue, light blue, or white. In infrared the blue haze goes away! I get nice, sharp, high-contrast pictures at all altitudes.
The next post will be about how to make infrared pictures, at least how I do it.