The Glow Around The Corner

One of the few sources of colored light that this article does NOT discuss is this icon of 1980s style, the Plasma Ball. Image by Bernhard Renner from Pixabay, cropped by Mike
Just to prove that the recent two-and-a-half-part article RPGs In Technicolor (part 1,part 2, part 2a) weren’t the last word on the subject, I thought of this topic of discussion.
Picture a room in which your character is located. A partially-closed door leads to a corridor beyond. Somewhere down that corridor, something is glowing in the night, casting beams of light through the crack at the bottom of the door.
The color and behavior of the glow will play a pivotal role in interpreting this situation. And the genre/time period of the setting will also make a big difference.
Here’s a quick list of contender – they aren’t the only choices, but they are a good start:
- Red Glow, ebbing and flowing
- Red Glow, steady
- Yellow Glow, ebbing and flowing
- Yellow Glow, steady
- Blue or Blue-white glow, ebbing and flowing
- Blue Glow, steady
- Green Glow, ebbing and flowing
- Green glow, steady
- Purple Glow, ebbing and flowing
- Purple Glow, steady
- White Glow, ebbing and flowing
- White Glow, steady
- Black Glow, ebbing and flowing
- Black Glow, steady

Image by Kirsten Mang from Pixabay
Combustion
The first one is fairly universally associated with fire. And yet, when you look at the light a fire gives off, it’s more yellow-white than anything else. Sure, some really intense fires have sheets of flame that are red – I’m having flashbacks to the movie Backdraft.
But it should also be well-known to anyone who has done high-school chemistry that different substances burn with different colors. The bright blue of a Sulfur fire, for example, can be mesmerizing – until you smell the chemical product! Natural Gas has a blue color to it’s flame. Sugar burns a slightly green color. This principle is sometimes used in mixing additional compounds into candles to change the color of their light, and is used all the time in creating fireworks.
Matter of fact, if you want to research this aspect of the subject more deeply than I have done, the chemistry of fireworks is probably your easiest entry point.
Readers may also find this Wikipedia page on Colored Fire to be of value.
In digging up that link, Google also presented me with a quotation from the Wikipedia page on Flame: “The colder part of a diffusion (incomplete combustion) flame will be red, transitioning to orange, yellow, and white as the temperature increases as evidenced by changes in the black-body radiation spectrum. For a given flame’s region, the closer to white on this scale, the hotter that section of the flame is.”
Right, so that scratches several items off our list (or, perhaps better, ticks several items). If your character saw those down the corridor, he’s probably going to think Fire. Depending on the setting, it might be a Fire Elemental or a Demon, but he’ll assume something is burning.

Image by Julia Kaufmann from Pixabay, cropped by Mike
Electrical Phenomena
Blue and Blue-white are also associated with electricity, and especially to electrical sparks. This association comes from the biggest sparks of them all, Lightning bolts.
For some reason, children always seem to think that lightning is yellow – an odd thought that just came to mind. Maybe in your world, there’s something to that, some deep racial memory that observation leads the rest of us to set aside?
In general, electrical phenomena are steady or momentary. The steady ‘burn’ of a light-bulb, for example. Quite often, when such are not steady, that’s indicative of a problem of some kind – anything from a neon tube that’s about to burn out, all the way up to electrical arcing.
Characters would obviously interpret this accordingly, and use it as a basis for action. But it’s not the only source of Blue Glows that we might want to consider.

Reactor core of the Idaho National Laboratory’s Advanced Test Reactor (ATR). By Argonne National Laboratory – originally posted to Flickr as Advanced Test Reactor core, Idaho National LaboratoryUploaded using F2ComButton, CC BY-SA 2.0, Link
Radioactive Decay
Okay, now things are getting serious. This is a steady bluish green glow, and relatively dim, and it’s called Cherenkov Radiation (sometimes spelt Cerenkov Radiation). It can also look like a bluish purple.
Cherenkov radiation is, according to Wikipedia, “electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium at a speed greater than the phase velocity (speed of propagation of a wave in a medium) of light in that medium.”
So… take water and add a radiation source. But (and a lot of people don’t realize this), light in air is 89,911 meters per second slower than in vacuum – and so Cherenkov Radiation can also occur in air.
Something radioactive this way comes? That’s either cause for concern, or cause for Really Major Worry, depending on genre.

A 1950s Radium Dial, previously exposed to UV-A light. Image by Own work, CC BY-SA 3.0, Link, cropped and slight color adjustment by Mike
Other colors are possible. Radium glow is generally thought to be green, and this is the basis of a myth that everything radioactive glows a steady greenish color: Where Did the Myth That Radiation Glows Green Come From – Mental Floss – “When mixed with phosphorescent copper-doped zinc sulfide, radium emits a characteristic greenish-blue glow,” says the article.
Most modern glow-in-the-dark items don’t use radioactivity, they use photo-luminescence, in which sunlight drives an electrochemical reaction which ‘charges up’ the glow, which is then released in the absence of light (i.e. darkness) to make the object glow a specific frequency (dependent on the compound). These are often a very similar color to ‘radium green’, but I’ve also seen everything from lime green to bright yellow.
Anyway, without the phosphor (the added chemicals that glow), radium excites the nitrogen in the air enough that the radium glows – a pale blue, similar to that of an electric arc.
But this would be a far steadier glow than any electrical arcing, which characteristically seeks out the path of least resistance, which varies constantly, and so dances around all over the place.
But we’re still not done with blue. Or with electricity.

One of the most famous displays of neon lighting adorns the Las Vegas strip. It actually looked a lot like this when I was there, back in the mid-70s – I’ve played video games in the Golden Nugget (I was under-aged, so no poker machines permitted). This photo is from 2013, long after the hotel we stayed in (The Flamingo Hilton) was knocked down and replaced. Image by romanov from Pixabay
Neon Lighting
One of the most common sources of colored light in the 20th century is neon lighting – in which the gases within the glass tube (usually neon, hence the term, but not always) glows in different colors. Another way is to put neon into a tube made of colored glass.
The resulting effect is a stock image in Noir formats. Pools of colored light, shadows in light, characters silhouetted by colored light – the list goes on and on.
Neon lighting isn’t dramatic or threatening in and of itself – it’s all in what you do with it.
Sci-Fi Lighting
Time for a drop-in section, I haven’t done one of those for a while! While searching for the image that heads this article, I came across the picture below. The careful use of illuminated elements – neon or otherwise – can be a great establisher of a sci-fi environment.
And I don’t know anyone who doesn’t react when a bank of green LEDs suddenly turn red, or worse still, flashing red!

Image by Artie_Navarre from Pixabay, cropped by Mike
Spectral Phenomena
Ghosts, Specters, and other sorts of spectral phenomena are frequently described or depicted as having a blue-white glow. Quite where this comes from, I’m not sure. Neither is anyone else, I don’t think.
It’s certainly a more common phenomenon in modern depictions, but that comes from two associations: first, we’re more familiar with, and accustomed to, glowing phenomena; and second, thought is electrical (well actually, it’s electrochemical) and electricity is blue-white. Frankenstein’s monster was given life by lightning, and there are the experiments with frog legs and electricity conducted in the early days of electrical experimentation that inspired Mary Shelley. So at least part of the story will be the association with electricity.
Part of it will be that artists typically want some means of showing that this is a non-corporeal being, and one successful metaphor for doing so has caught on. Since the number of artists and the number of subjects being depicted has increased exponentially since the 19th century, there has been more of everything produced – and so examples abound, and a popular zeitgeist has been established. Closely-related to this thought is that the spectral glow is dramatic and contrasts strongly with a darkened scene – it could almost be described as melodrama in art – and this also encourages this depiction.

Image by Artie_Navarre from Pixabay
So powerful is this association that the term “ghostly glow” is still in use today. It is, perhaps, noteworthy that many depictions of Death also show him glowing…
Someone once suggested that it was because ghosts should only show up in moonlight, but I reject that premise – moonlight is more bone yellow-white in color, and is rarely strong enough to show any color at all (we see black-and-white in the absence of sufficiently strong light, or perhaps that should be black-and-gray!)

Image by Enrique Meseguer from Pixabay, slight crop by Mike
Magic
Now we’re getting down to the creatively-interesting stuff!
In many campaigns (perhaps inspired by Octarine, Terry Pratchett’s literary creation) give a distinctive color to magic in its various forms.
In particular, one GM caused great hilarity at his table when he decided that “Detect Magic” caused magic items to glow with Cherenkov Radiation. The players immediately decided that much of their booty was radioactive and had to be safely disposed of… more than twenty years later, he still dines out occasionally on that story (which continues on for quite some time).
Personally, I think Pratchett may have been inspired by the Troxler Effect optical illusion that I featured in A Sharp Lookout: How Much Can You Adventure?, in which an afterimage creates a color that doesn’t really exist. In the example shown there, the absence of a purple causes a yellowish-green spot to appear when you stare at the cross for a few seconds. Part of the appeal of this theory, I must add, is due to the hilarity of the notion of would-be Wizards looking at everything cross-eyed, something that I feel would probably have appealed to Terry!
Just to be distinctive, and because there don’t seem to be very many natural phenomena staking out the space, I frequently use violet/purple glows as the color of magic.
Clerical Magic gets a white, gray/green or black glow according to the alignment of the caster or his power source.
But I am just as capable of saying that there’s no visible aura or radiance and someone who appears to be using somatic gestures in the casting of a spell might just be waving his arms around.
(I had some players really going for a while with this and a gifted actor wearing a ring of permanent Unseen Servant once. They decided that he must be the most skilled practitioner of Telekinesis (the spell) ever. I don’t recall them ever discovering the truth – that he was a con-man taking them for a ride. Might have happened, it was a long time ago, but I don’t remember it.)
The glows achieved several things by implication. They implied that there was some commonality between the mechanisms (because every spellcaster had a glow). They implied that there were differences, because the glows were all different in color. They implied that there was an absolute morality that was reflected in the casting of clerical magic, but that there was something special about Druids and Rangers (who got Green), while Wizards sort of skated above the whole Absolute Morality issue – implying that it didn’t apply to everyone. In fact, as I recall, this was a world in which the Gods could do anything, except break the strictures of their inherent morality. They were absolutes and primal forces. But whenever they did something, this always led to them going too far and causing all sorts of unwanted side-effects – so they had to work through mortal intermediaries to impose constraints on their divine power. This was also a world in which the gods were children (because nothing could really make them grow up) who were doing their best to pretend to be the grownups in the room – they were in awe of Wisdom, which is why they tied access to their powers to that stat – that, and the fact that it meant that their followers would use their powers Wisely, at least most of the time – the one thing that the Gods couldn’t do themselves.
In the end, though, all this comes back to “Detect Magic”. Back in the AD&D days, when I started playing, it was a “Universal” Divination spell that permitted the caster to become aware of what was magical and what was not. Details were limited, as though it were obvious what was meant.
Endless hours could (and were) spent deliberating on the significance, impact, and specifics that weren’t covered. “I cast an illusion spell on Harry, does he now detect as Magical?” sort of thing.
Later editions cleaned things up quite a bit, but locked users into one specific interpretation. That’s quite common, and one of the driving forces behind “Old School Gaming” – in which the GM’s/Players preferred meta-framework doesn’t match the one used by the writers of Edition X. If there are only a few differences that you can’t live with, you can House Rule your way around the problem; if they are more substantial and numerous, you may need to retreat to an earlier edition (perhaps importing some parts of the later edition that you did like.
On its surface, this presents a continuity between D&D (1st Ed) and all subsequent generations of the rules, as though they were arrayed on an arc around it, each generation bound to both the original source material and to the edition that preceded it. The reality is a little more complicated, but let’s go with that. Campaigns and preferences can fall anywhere within the resulting field. Your game might be mostly 3.x, with a little 5e (ignoring 4e, rightly or wrongly) and a little 2e thrown in, and a slightly old-school attitude. This would be positioned somewhere near the higher side of the 3.x arc (the one closest to 4e, which is blacked out because this GM is ignoring it), and hence to 5e, and about 1/3 of the way towards the hub, where lives original D&D.
You can complicate this simple metaphor in all sorts of ways, but that’s good enough for this purpose, which is simply to state, there are no wrong answers. At least, not inherently wrong. They are all sorts of wrong answers on a playing group by playing group basis, according to personal preferences. A similar selection – a set of acceptable answers – describes GM-by-GM preferences – what a given GM finds acceptable and what he doesn’t. Where the two sets overlap (and there is no certainty that they will) is the right place to locate a campaign for that specific GM and that specific playing group. There may be (and usually are) multiple such overlaps, or there may be just one. That doesn’t matter.
Nor are there any absolutes here – if the GM is skilled enough, if his game is entertaining enough, players will stick with it even if it is not their preferred genre, sub-genre, rules interpretation, or color of the week. Skill and talent can overcome any such difference – only the heights that have to be scaled, vary.
Another of the oft-debated questions was “If I cast Detect Magic on a Magic Shield, does Phil (playing another Wizard) also see the glow? Does Harvey (playing a Cleric)? Does Walter (playing a fighter)?”
The answer to this question has big implications – if it’s a ‘yes’ all round, either the GM is being lazy or economical (because such things as differences of perception always slow things down), or the spell has had some temporarily-transformative effect on the magic of the item. If the answer is ‘no’ to any one of those questions, then limitations on perceptions begin to play a role. And if the answer is ‘no’ to all of them, then the spell has affected the caster’s perceptions and not the item at all – in which case, the caster should be able to look at other items and discern them as magical, something that does not happen if it’s the target that is somehow transformed. “Yes” answers all round remove one restriction on the spell but impose another. It’s a personal choice, but can be a simple way of differentiating one campaign from another – and it can be fun exploring the implications!

Image by Aaron Escobar, CC BY 2.0, via Wikimedia Commons, crop and color manipulated by Mike
Televised Aberrations
Anyway, getting back to the main topic of discussion, what does that leave? Not much. But most of the processes described have referred to natural phenomena that vary in intensity from moment to moment, causing flickering. One could argue that the magic glows may be steady, but I’ve always preferred to think that the glows were strongest at the fingertips or from the palms of the hands – which means that if those hands are waving around, the light will appear to flicker when it is cast upon a surface and not perceived directly.
I have good reason for this preference: it gives me more license for description. With a steady glow, once you’ve mentioned the fact and added the color (if that’s significant), that’s the end of it. Getting more specific gives me more description that I can use.
But I haven’t yet mentioned one source of flickering light that I see almost every day – a television in another room. The light is usually flickering white – but it’s very dependent on the images on the screen. Something underwater is predominantly blue, for example.
A very mundane explanation for a glow, in stark contrast to the reasons for alarm suggested earlier.

Closeup of a CRT Screen, Image By Marcin Floryan – Self-photographed, Public Domain, via Wikipedia Commons, cropped by Mike
Televisions make colors – or at least, they used to – with arrays of dots of different colors. That may have changed with newer technologies – but our eyes haven’t changed, so the general principles still seem to apply.
So, have you ever seen a color TV in which something has gone bung and the screen is suddenly monochrome? All green, or blue, or red? I certainly have, and while it doesn’t happen often, it can be a source of monochrome glow – it can even flicker!
But a more likely explanation is some sort of screen saver. These have fallen out of favor lately, because modern screens are not as susceptible to burn-in damage, but there was a time when they were ubiquitous.
UFOs & Aliens
A lot of these are supposed to glow. Sometimes different colors.
One of the most memorable uses of light on a cinema screen comes in the classic Close Encounters Of The Third Kind – a strong moving light or lights behind a venetian blind in the abduction scene.

This screen-grab from Amazing Stories dot com. The Film is © 1977 Columbia Pictures; usage here is for review purposes and claimed as Fair Use.
Glows That Tease
And that brings me to the ultimate value of a glow – it teases without showing a thread directly. This can be a lot scarier, a lot more dramatic, and a lot more exciting. It’s akin to hearing a scraping sound from the wall beyond your room, as though someone were trying to claw their way through (or out). But a glow implies that the source of the glow has access to you, whenever it wants, and so can be more threatening. Other senses can also be used, but far less effectively a lot of the time – witness the Original-series Star Trek episode Obsession, in which Kirk becomes obsessed with destroying a cloud-like hostile entity which he recognizes by a ‘sickening, honey-sweet’ scent. Unfortunately, while that is a reasonable signature of sorts, it isn’t particularly threatening – but nothing is made of that subterfuge.
But scent can be threatening – I don’t remember the reference, but the phrase “the stink of a charnel house” lives with me. Attempting to attribute it, a google search found this story about an Ohio ghost with the smell of blood and decay that the term conjures up from the website Haunted Ohio.
But even more threatening than the scent alone would be, would be to establish the connection between an apparition and the scent of death. This would tend to hyper-sensitize even the staunchest of military men, triggering them every time they were exposed to the scent – whether it was from the kitchens, or a dog’s feeding ground. If subtle enough, they might even be triggered to full alert without even recognizing the cause.

Image by PublicDomainPictures from Pixabay, contrast and tonal values tweaked by Mike
A formidable narrative weapon. And one that proves, once and for all, that there’s more to glows than meets the eye. What do glows of different color mean in your world?
Glows will always be threatening until proven otherwise. Don’t neglect them and don’t ignore them! There’s a glow coming from the alleyway you are approaching, and a chill wind in the air…
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