What do Luke’s Lightsaber, the main deflector dish of the USS Enterprise-D, and J.J. Abrams’ ubiquitous lens flare have in common?
What characteristic do the engine of the Millenium Falcon, Dr. Manhattan of the Watchman, and the diva of the Fifth Element share?
I’ll make it easier. What color unites the N’avi of Avatar, the light-cycles of Tron: Legacy, and the cover art of Prometheus?
The answer to the riddle: All of these things are electric blue. I’ve written in the past about how electric blue is a kind of signal of science fiction, one that shows up in a statistically robust way when performing an unbiased analysis of the color spectrum of movies. Electric blue can be found in your major sci-fi franchises:
And in the box art of minor box-office bombs:
In your kitschy classics:
And reaching across media:
Once you are aware of the pattern, you begin to see it everywhere. Gaze upon, for example, the box art for the list of top science-fiction films on IMDB. Electric blue is such an all-pervading signature of science fiction that it can scarcely be ignored.
I realize that the above screenshots show a range of colors, not a single hue. It is fair to wonder where electric blue stops and some other color begins. Perhaps I am merely calling things electric blue which aren’t. Furthermore, even if you are willing to allow that electric blue is a characteristic of many science fiction films, left unanswered is the question of why. I intend to approach both of these quandaries herein.
To scrutinize electric blue further, I digitized one of the bluest movies I could find. I picked Tron: Legacy not because it’s a good movie (more on this later), but rather because its usage of that particular portion of the color spectrum seemed like a very considered choice. Indeed, everything visual and auditory in TL is carefully and audaciously curated. Along with the color palette, the design of each object in the world of TL is exquisitely conscious, and perhaps overly geometric:
Never mind, for now, that the visual artistry of this movie is about the only thing it had going for it; that’s all I’m interested in anyway.
The way I digitized it is like this: I took a picture of the movie, as it was playing, once per second. Then I read those pictures (more than 7000 of them) into the computer’s memory, sampling 160 individual pixels per picture, which gives me a very sizable, and hopefully representative, subset of all of the colors in the movie.
Colors, as perceived by the computer, occupy a three-dimensional space. They consist of mixtures of red, green, and blue, and the precise blend of these three numbers determines where they sit in this space. We can visualize that by looking at a plot of Tron’s colorspace:
There’s a graph you can manipulate here. One whole half of Tron’s colors falls somewhere along the continuum of what I, subjectively, would call electric blue (the other half, in some neon shade of orange, is for the bad guys. Here’s to simplicity.). You ought to be able to observe the enrichment of electric blue I’m talking about, which corresponds to details like the identity discs that (for some reason) the people in Tron use to fight each other:
I’ve long wondered why the various science fiction artists picked this sub-spectrum of colors. What, in particular, about electric blue makes it so useful for the denotation of science? The particular shades or colors aren’t especially rare in nature, often being found in the sky or the surface of large bodies of water. In other words, electric blue isn’t unique because of its rarity in the natural world.
Of course, I recognize the possibility that electric blue doesn’t have any connotations but the ones that have been built for it. In other words, it is entirely possible that electric blue signifies science fiction not due to any particularly compelling reason, but rather just by convention. Once famous artists (George Lucas, or Stanley Kubrick, or whomever) began to use it, maybe it just caught on.
However, I don’t think that’s the case (or at least not solely the case). I recently stumbled across a picture which makes the case in pixels far more articulately than I could make in words. Here is that picture:
This photo depicts a nuclear reactor, and so long as you are not colorblind or an incorrigible skeptic, you will see an immediate correspondence in the spectrum of this picture and Tron and the handful of other illustrations of electric blue I provided above. Here is a picture of the color spectrum of this picture, computed in the same way I analyzed the movie, to compare against Tron: Legacy.
The shape of the color spectrum is a peculiar, twisting curve, undoubtedly the result of some arcane, mind-bending property of physics I will never understand. Yet, it matches the particulars of not just Tron, but a whole gamut of science fiction movies. Specifically, the upper reaches of the spectrum, where the blue fades into white, seem to me the most commonly used (and these colors correspond to the heart of the reactor in the above picture).
Brief science interlude: this light is a product of what’s called Cherenkov radiation. Cherenkov radiation is a consequence of the process of radioactive decay that powers nuclear reactors. As particles are broken apart, the high-energy products shoot away from the reactor core. They then enter the pool of water surrounding the reactor. Water constrains the speed of light to about 3/4ths of its velocity in a vacuum. As the celeritous particles hit the water, they must slow down, and in so doing, they destabilize the water, which in turns emits high-frequency radiation in the visual spectrum–a fancy way to say ‘blue light’. This phenomenon is the analog of a sonic boom, but instead of being a consequence of the speed of sound, it comes from the speed of light. (Don’t mistake me for an expert: I base this knowledge completely on cursory internet reading).
I recognize that so far, I’ve been primarily hand-waving, that is to say, making rhetorical arguments on the basis of intuition. But one of the advantages of having quantitative measurements of colorspace is that we can do better than that. I can actually show you how similar science fiction is to Cherenkov radiation. So here is a plot of the colorspace of Tron: Legacy, with brown spheres overlaid upon it corresponding to the position of the colorspace of the radiation.
It’s not a perfect fit, by any means. As I suspected, you see the greatest overlap at the brightest corner of colorspace, where the teal-shaded electric blue turns into pure white. I would contend that the shared overlap is significant, nonetheless.
I did some research into when the first pictures of Cherenkov radiation appeared. Cherenkov, the physicist who first empirically demonstrated the radiation and for whom it was named, won a Nobel for his efforts in 1958, and so I strongly suspect that the earliest pictures of the eerie azure glow must date from somewhere near that time. That puts it close enough to when some of these movies (Star Trek/Star Wars) were coming out that I can at least imagine it having an influence on the mind of the visual designers of those films.
I won’t say that Cherenkov radiation is the sole source of the auteur’s fascination with electric blue. As I mentioned above, probably a great deal of its appeal is that the shade has been co-opted previously to symbolize the effects of science fiction. Even so, there is something undeniably futuristic about Cherenkov radiation, something beautiful and ghostly to the pale blue light. That nuclear reactors should emit this weird color is a rare quirk of fate. That filmmakers should have adopted the colorspace in and immediately around it to serve their own purposes is, I suspect, more than coincidence.
Update: I am not the first to have noticed the correspondence between Cherenkov radiation and Dr. Manhattan’s odd coloration. Physics professor Jim Kakalios apparently speculated in the same direction in an interview of which I was unaware when I first published this piece.