I’ve been doing some research on different types of vision, and apparently what we humans see is the visible wavelength of light – i.e. the colours you see in a rainbow. But many animals, and especially insects, see things we can’t. For example, the humble goldfish can see in both infrared and ultraviolet wavelengths.
Without getting too technical, think of wavelengths as a line of spaghetti of different lengths, from shortest to longest. The shortest bits are in the ultraviolet wavelength. The longest bits are in the infrared wavelength, and there in the middle are the colours we humans can see. Blue is longer than ultraviolet and red is shorter than infrared.
For the purposes of my research, infrared was what I was looking for, but what is it, and what does it look like?
We can’t see infrared, not with the naked eye, but we can feel it because infrared is basically the wavelength of ‘heat’. In visual terms, the colder something is, the darker it appears. The hotter something is, the brighter it looks.
Confused? Good, so was I. As a visual creature, I needed to be able to visualise something that is essentially, invisible. Luckily, we have developed special cameras that can:
- detect infrared wavelengths, and
- translate them into colours on the visible spectrum – i.e. into colours we can see.
Generally speaking, infrared cameras translate cold images into dark colours such as dark blue or dark purple. As areas of an image warm up, the heat is translated into brighter colours – from red to orange to yellow to white.
In the screenshot below, the infrared camera shows a cold frying pan on a stove top [the yellow labels are mine]:
To get an idea of what the camera sees as the pan heats up, please have a look at this short video on the National Geographic website:
It’s only a very short video [1.18 minutes] and well worth the look [if you have a phobia about mosquitoes, avert your eyes for the first twenty seconds or so]. Isn’t that amazing?
More on why I’m doing this research at a later date. 😀