Spy Toys: Seeing in the Dark

When writing our stories, we need to understand all aspects of our characters to help bring them to life on the page. Sometimes, that all important characterization is not about the way a character thinks or acts, but rather the toys that they have at their disposal. Let's face it, James Bond wouldn't be the captivating creature he is without all the gadgets and specially designed toys given to him by Q. Maxwell Smart would be nothing without his shoe phone. Batman would be just some spoiled billionaire without the famous gadget belt. And Judge Dread... Well, Judge Dread is Judge Dread, and he can do whatever he wants, even if it's blow up half the city.

But what about the men and women who are the real counterparts to our favorite spy-like fictional characters? Sure, they have their guns, the knives, and whatever other weapons they can get their hands on, but some gadgets at their disposal feel like they come out of science fiction. I'm talking about the toys they use to help them see their targets.

Some time ago (what honestly feels like ages), I wrote about the real technologies that spies use for imaging over long distances. A variant of that original blog post has been published in the book Putting the Science in Fiction, and I spoke a little more in depth about technologies on my radio show ConvoScience (along with a little more about the effects of the atmosphere on stellar light and satellite imaging on my personal blog).

While I could talk about the effects of the atmosphere on long-distance imaging until the cows came home, I thought it would be fun to talk about another series of imaging toys at the disposal of real assassins, spies and SAS. Today, it's about the toys (and techniques) they use to see in the dark.

The Developed Night Vision

Before we get into the toys, I thought it was important to mention something about natural night vision.

Humans, like animals, have an innate ability to see in the dark. Animals such as cats and wolves will always be able to see better in the dark than a human could, simply because their optic nerves work differently to the way ours do. However, some humans can see better in the dark than others. The reason: they work at it.

The amount of light that we need to discern detail is regulated by the iris and pupil of our eye — the color part of our eye and the black dot in the center. In low light levels, our iris retracts, making the pupil bigger and allowing more light through. In total darkness, our pupil can grow to almost the same size as the outer diameter of our iris. That's a lot of light. However, if we were to suddenly turn on the lights, our optic nerves get overloaded with light information, temporarily blinding us. It's not until the pupil becomes that smaller size (and our optic nerves recover from the over-stimulation) that we can see again, often with an after image of the world as we were blinded. Throw modern society into the mess, and you have a recipe for a population with poor night vision.

In the past, humans actually had exceptional night vision. The reason: they weren't surrounded by so much ambient light at night. Street lights weren't as bright, and indoor activities were conducted under firelight and candles. Today, our electronic world has resulted in these bright bulbs that actually destroy our natural night vision.

Those who work in fields such the military, intelligence agencies, and astronomy (yes, astronomy) actually know firsthand the harmful effects of certain lighting on night vision. Naval vessels will have the ability to illuminate the bridge with red lighting instead of white. Astronomical instruments on a telescope dome floor use red LEDs. And assassin/spy/SAS characters will always carry a flashlight with a red filter into the field.

I won't go into the detailed science as to why red filters are better to preserve night vision, not on this blog anyway (perhaps on my personal blog in the future), but for the moment, you will need to blindly accept that there is real science behind it.

Preserving/Improving Your Own Night Vision

Those in the intelligence community will work to maintain their night vision. My own night vision is pretty good too (I worked as an astronomer for over 10 years). Here are some things that you can do to help improve your natural night vision.

• Obtain a red filter for your flashlights. (Mine have a white and red LED settings, and I get grumpy with those with white-light flashlights when they shine them in my face.)
• At night, use low brightness settings on your backlit devices (i.e., computer monitors, phones).
• Play with the nightmode settings on your smart devices. (iPhone and iPad can set a reddish hue to backlighting, which is kinder on the eyes.)
• Use "warm" lightbulbs in your living areas of your home. These are redder lights look orange.
• Avoid situations where you're sitting in the dark staring at a bright screen. (Movie theaters are a nightmare for night vision.)
• In your car, set the lights on your dashboard to a dim setting (assuming you have the ability on your vehicle).
• If you are driving at night, pulling out from a well-lit area, find a dark spot and sit there for a while to give your eyes time to adjust.
• Don't look directly at streetlights or the headlights of on-coming vehicles when driving.

You will find a whole range of advice on the internet about diet and all that jazz, but just avoiding bright lights at night will provide noticeable improvement in your night vision.

When Natural Night Vision is Not Enough

Although those in the intelligence community work to maintain their natural night vision, sometimes, they need a little added assistance. Let's face it, cameras just don't cope in low light levels. If you want to get good night shots, you either need to use long exposure (which can result in image blur), or play with some other toys.

I hinted at it before that naval vessels use red lighting on their bridges for night maneuvers. Well, they're not alone. Military cargo planes will use red lights in their cargo areas at night too, but trying to take a picture... The red light alone is not enough. If you were to combine the red lighting with night vision goggles (NVG), instantly the detail pops out.

Your traditional NVGs, like the one used in the images above, works on the concept of light enhancement. Basically, they collect all the light that they can (just like your eye would), but through the magic of lenses and other electronics, they amplify that light, so you can see the details.

Okay, this is a serious oversimplification of the technology, but unless you're a science geek, you're probably not going to really care about the specifics. (When I get a chance, I'll go into the specifics of the science on my personal blog or my science radio show.)

There is a second kind of NVG that is much more fun to play with. This kind is based on thermal imaging. The idea is that all objects are either be heat producing or heat absorbing. Human beings and animals are heat producing.

There are different variants of thermal imaging systems available, focusing on different ranges of the electromagnetic spectrum.  The most common thermal imaging systems use are for infrared.