Vision and Light

The most fundamental tasks of adventuring — noticing danger, finding hidden objects, hitting an enemy in combat, and targeting a spell, to name just a few — rely heavily on a character’s ability to see. Darkness and other effects that obscure vision can prove a significant hindrance.

A given area might be lightly or heavily obscured. In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have Disadvantage on Wisdom (Perception) checks that rely on sight.

A heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the Blinded condition (see Appendix A) when trying to see something in that area.

The presence or absence of light in an environment creates three categories of illumination: bright light, dim light, and darkness.

Bright light lets most creatures see normally. Even gloomy days provide bright light, as do torches, lanterns, fires, and other sources of illumination within a specific radius.

Dim light, also called shadows, creates a lightly obscured area. An area of dim light is usually a boundary between a source of bright light, such as a torch, and surrounding darkness. The soft light of twilight and dawn also counts as dim light. A particularly brilliant full moon might bathe the land in dim light.

Darkness creates a heavily obscured area. Characters face darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon or a subterranean vault, or in an area of magical darkness.

Darkvision

Many creatures in fantasy gaming worlds, especially those that dwell underground, have Darkvision. Within a specified range, a creature with Darkvision can see in dim light as if it were bright light and in darkness as if it were dim light, so areas of darkness are only lightly obscured as far as that creature is concerned. However, the creature can’t discern color in that darkness, only shades of gray.

Passive Checks

A passive check is a special kind of ability check that doesn’t involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster.

Here’s how to determine a character’s total for a passive check:

10 + all modifiers that normally apply to the check

If the character has Advantage on the check, add 5. For Disadvantage, subtract 5. The game refers to a passive check total as a score.

For example, if a 1st-level character has a Wisdom of 15 and proficiency in Perception, he or she has a passive Wisdom (Perception) score of 14.

The rules on hiding in the “Dexterity” section below rely on passive checks, as do the exploration rules in chapter 8, “Adventuring.”