Light

Light will make a projectile emit light in a circle 267 pixels in diameter as it flies, temporarily revealing darkness.

Each stack of it increases the brightness linearly by increasing the alpha channel of the particle by .55 and increasing the size of the particle by 2.5 pixels in all directions.

Tips

 * Because it is quite common early on this can be quite useful if you want to go into the Dark Cave if you can get a wand that can consistently cast it, though it should only be used as a guide to the max health that's there as using explosives is far more available and successful.
 * Drilling shot, while letting you attack enemies through walls, is much more effective alongside this modifier, as it lets you attack them without having to explore where they currently are, although a lot of spells already emit some light.
 * You can use this to identify threats and scope out an area although the light produced by this usually doesn't last long enough to take in that much information.

Trivia

 * Despite other modifiers having a mana drain of 0, and being objectively more useful, Light still has a mana drain of 1.
 * The outer third of the circle is almost always dim and has a very hard time illuminating anything, even with a hilarious amount of them on a wand at once.
 * The light created by the spell is actually just a particle which is used in a lot of other particles and spells that create light, like in explosions. The name of the particle is actually "explosion" not "light"

Gallery
A player casting a drill shot spark bolt with 1 light, and a player casting the same thing but with 132 light.