Tuesday, May 14, 2019

Continual light/flame - how common are they?

So I was prepping this adventure in a castle where I figured that several rooms would be dark - the servants have been prevented by mayhem (why the PCs are called in) from lighting or replacing candles, torches etc. Then I realized - silly me, this castle is owned by a powerful wizard, there should be continual flame spells everywhere.

(In several editions of D&D, there is a "continual light" spell - a light that lasts forever.  There is usually a cost (in 5e, it's 50 gp's worth of ruby dust), so you can't do it willy nilly.)

But then I started thinking about it... Continual flame spells are expensive and should be rare... or *are they*?

Let us consider not a mage or a rich noble, who of course can afford it, but a modest artisan. He's doing ok for himself, living a lifestyle of 1.5 gp a day (halfway between modest and comfortable by 5e standards). He needs light every evening in a single room, for 3 hours on average. Nothing extravagant. This, however, has a cost. If he uses a lantern or lamp, this is about 5 cp/night. Candles would cost him 3 cp/night (and shed less light). Torches are as cheap and shed more light, but the smoke... so let's stick with an oil lamp - he's has a little bit of money, after all.

At 5 cp a night, this adds up to about 18.25 gp a year. So in other words, a continual flame spell would pay for itself in less than 3 years! People in the middle ages were capable of long term planning - they did long term projects for great gains - building a fence, planting an orchard, or building a cathedral. Our artisan could, for example, limit himself to candles and in less than a decade, take the spare 2cp/night to buy the continual light, and save that 5 cp a night for other things.  The spell is safer (no fire risk) and sheds no smoke. And his light can be passed on to his children etc.  

I do have to note that this is just for the material cost, not the fee to the caster.  But even if the cost is doubled, it's still a good deal.

Given that continual light spells can be cast by low-level casters, I can see this as a common, harmless way to raise funds. Want to fund your magical research but low on funds?  Make some magical lamps and tell them to the local baron!  Temples could sell them too to the faithful, those cathedrals need maintenance - they might be hesitant to give magic to the masses, but (same as a potion of healing), what harm could *light* do? Even very humble peasants may have one - the "family continual flame", passed down from generation to generation - it was given to great grandfather Jeb by the bishop as a reward for his help in fighting off the goblins - or some other colorful story. 

Having continual flames everywhere may be too "magical" for the setting you want to create. But the economics tell us that, unless casters are *incredibly* rare, they should be all over the place.  

Another quick bit of number crunching.  In the kingdom of Notsomagicland, there are 10 million people, but only, at any given time, 100 casters (on average) capable of casting continual flame.  They only deign cast the spell once a year, and the spell has a duration of 1000 years (it's permanent, but accidents/loss happen).  So... with this limited number of casters, who rarely use their magic, there are 100 000 magical lights around at any given time... Now imagine if there are 1000 casters.  And they cast it 1/month... 

Given that in Yoon Suin, the ruling class are almost *all* spellcasters and it is a very large city... you're going to have a lot more than 100 casters.  But I think that in Yoon-Suin, continual flame would be seen as *boring*.  Oh sure your room is lit by continual flame.  I use candles... made with yakmen tallow.  You can smell their anger!

Interestingly, in Veins of the earth, light is incredibly precious underground, and 1 gp = 1 hour of light.  So a continual flame would be priceless.  I imagine for that game the spell would have to be modified, otherwise the economy doesn't make sense.  And that's ok!  Change away, it's your game.  


  1. That sounds like the kind of thing that will be the target of sumptuary laws "to prevent the ostentatious use of magical enchantments by persons of low breeding".

  2. I begin to see why older editions of D&D, despite exhorting the importance of carrying a light source, also felt safe assuming that players would always have one.

    The idea that "continual lights" might last 1000 years (or longer!) makes me think that there's a post-apocalyptic future to the D&D world where EVERYTHING glows and it's NEVER dark because the world has filled up with permanent, indestructable glowing objects. Kill any animal and light pours from the wounds due to all the indigestable enchantments it's eaten. Somewhere in the ocean is an entire island made of nothing but continual lights carried by the currents to one spot. And anyone who can manage to travel to one of the few dark places left in the world is in for a surprise - there are even lights in the sky, though you can't see them most places because the lights on the ground drown them out. It would combine the worst features of plastic pollution and light pollution from the real world.

    A single wizard who knows the "continual light" could rapidly fill the Veins with so many permanent, priceless lights that darkness is soon banished from the underworld, nothing more than a myth parents tell to their children.

    1. Literally light pollution! I love it. Although this would only occur if continual light is not vulnerable to dispel magic spells. This is where the "tiny details" of the version of D&D matter. For example, in 5e you couldn't take out the light spells by accident while trying to cast dispel magic on a foe, but in older editions you might.

      So a showdown in the town square might result in the party being fined several hundred GPs for destruction of lights....