The Effects of Light on Combat

by Joe Wetzel (joewetzel at gmail dot com)

Recently, our gaming group experimented with a mapping program instead of drawing out the maps. The mapping program had the option to only let players see to the edge of their light sources. This restriction had interesting effects on our game’s dynamic.

Our group’s fighter who would usually charge into battle always stopped at the edge of the lit area. Other characters could not shoot at foes outside of the light without a major penalty. It would be a shot in the dark. Literally. Ok, sorry about that.

A character shooting even just outside the area of light would barely see the target if he would see anything at all. If you’ve ever gone camping you can understand this: When you’re near the campfire you can see things in the light well, but there seems to be a point where you can just barely make out an object if you really concentrate.

But the game system actually handles the issue of light by breaking things down into three categories:

• Bright light: All characters see clearly and creatures can only hide in bright areas if they are invisible or have cover.
• Shadowy illumination: A character can see dimly. Targets within the area have concealment, so there is typically a 20% miss chance. A creature in the shadowy area can make a Hide check to conceal itself.
• Darkness: In areas of darkness creatures without darkvision are blinded. The blinded creature has a 50% miss chance, loses his Dexterity bonus to AC, moves at half speed, and takes a -4 penalty on Search and most Strength and Dexterity checks, according to the System Reference Document.

The table titled “Table: Light Sources, Illumination Areas, and Durations” lists the area for most light sources’ bright and shadowy areas.

Table: Light Sources, Illumination areas, and Durations.

Item	Bright	Shadowy	Duration
Candle	n/a, only shadowy light	5 ft. radius	1 hour
Lamp, Common	15 ft. radius	30 ft. radius	6 hours/pint
Lamp, Bullseye	60 ft. cone	120 ft. cone	6 hours/pint
Lamp, Hooded	30 ft. radius	60 ft. radius	6 hours/pint
Torch	20 ft. radius	40 ft. radius	1 hour
Spell	Bright	Shadowy	Duration
Continual Flame	20 ft. radius	40 ft. radius	Permanent
Dancing Lights (Torches)	20 ft. radius each	40 ft. radius each	1 minute
Daylight	60 ft. radius	120 ft. radius	30 minutes
Light	20 ft. radius	40 ft. radius	10 minutes

But there is another factor to consider: some races and magic items have darkvision or low-light vision. Dwarves and Half-orcs have darkvision, so they can see without light. The presence of light does not spoil darkvision. Elves, gnomes, and half-eves have low-light vision which doubles the bright light and shadowy illumination ranges for that creature. Therefore these creatures using a torch would see targets 40 feet away in bright and they could see targets up to 80 feet away from the torch in Shadowy conditions.

That’s all by the book. But one more rule should be considered. If a creature is at the edge of the bright light range, and a target is directly in front of him just outside of the bright light range, should the target gain a 20% miss chance. Light simply doesn’t work in bands (bright light, then a sudden shift to shadowy illumination, then a sudden shift to complete darkness), yet for simplicity the game system has to have these categories.

Fortunately the rules for concealment include a clause that states, “Certain situations may provide more or less than typical concealment, and modify the miss chance accordingly.” Therefore I would argue that if a target is in the shadowy area and just within reach of the attacker there should be no miss chance or it should only be 5-10%.

However, I wouldn’t lower the penalties for the same situation at the border of the shadowy illumination and darkness areas. In this case the creatures are far enough from the light that they might have a general idea that their target is in a particular square and the shadowy creature might even be able to make out a bit of the creature in darkness, but the penalties (specifically the 50% miss chance) still fits the situation well.

The text above uses content published under the Open Game License.