Light
Light decides what you can see in the dark places of the world. It is part of the rules, not just decoration.
What light is
Every cell has a light level with four channels: red, green, blue, and ultraviolet (UV). For each channel, 255 means fully lit: a surface then shows its true color. More than 255 is overbright, and the surface brightens a little further. Colored light is real: a red crystal lights its surroundings red, and a surface lit only by red light shows only red.
A cell’s light is the sum of:
- the level’s ambient light (zero in most dungeons, so they are dark),
- sunlight, moonlight, and sky light under the open sky, dimmed by clouds (see Sun, moon, and sky and Weather),
- every light source that reaches the cell, and
- a little bounced light.
A special room can change that. A shadowed room drains all of it, and a sanctuary adds a faint warm glow of its own.
Light sources
Light comes from wall torches, braziers, lamps, magical crystals, glowing fungus, runes, lava, the altar, creatures that carry a torch, your own lantern, and the faint light of a spell circle around anyone with a buff or a hex on them. Each source has a color (its red, green, blue, and UV at the source), a brightness there (as normal eyes see it; see vision), and a reach in cells:
| Light | Reaches | Kind | Colour (red, green, blue, UV) | Brightness |
|---|---|---|---|---|
| Torch carried by a balor or a burning skull or a kobold or a nightmare | 6 cells | visible | 300, 180, 90, 0 | 198 |
| Wall torch | 7 cells | visible | 280, 170, 90, 0 | 187 |
| Brazier | 8 cells | visible | 360, 210, 100, 0 | 233 |
| Lamp | 6 cells | visible | 230, 200, 150, 0 | 202 |
| Candlestick | 4 cells | visible | 250, 195, 120, 0 | 201 |
| Arrow fire | 5 cells | visible | 260, 145, 60, 0 | 162 |
| Your lantern | 5 cells | visible | 250, 215, 160, 0 | 218 |
| Your lantern (Kindled, Lamplighter) | 6 cells | visible | 265, 228, 170, 0 | 231 |
| Lantern hooded carried by an animated lantern | 2 cells | visible | 125, 108, 80, 0 | 109 |
| Altar | 5 cells | visible | 220, 180, 90, 0 | 181 |
| Altar good | 4 cells | visible | 240, 190, 80, 0 | 192 |
| Forgotten altar | 4 cells | visible | 180, 180, 190, 0 | 180 |
| Altar evil | 4 cells | visible | 240, 50, 40, 0 | 89 |
| Light crystal (red) | 7 cells | visible | 340, 50, 40, 0 | 110 |
| Light crystal (green) | 7 cells | visible | 60, 300, 80, 0 | 233 |
| Light crystal (blue) | 7 cells | visible | 60, 110, 380, 0 | 119 |
| Light crystal (amber) | 7 cells | visible | 320, 220, 40, 0 | 227 |
| Crystal portal | 5 cells | visible | 180, 110, 320, 0 | 140 |
| Wisp carried by a corpse candle or a will-o’-wisp | 3 cells | visible | 110, 190, 170, 0 | 171 |
| Storm carried by an elder lightning elemental or a greater lightning elemental or a lesser lightning elemental or a lightning elemental or a thunderhead | 4 cells | visible | 150, 170, 360, 0 | 179 |
| Glowing fungus | 3 cells | visible | 0, 24, 13, 0 | 18 |
| Faint rune | 4 cells | UV only: invisible without UV sight | 0, 0, 0, 180 | 0 |
| Lava | 4 cells | visible | 300, 110, 30, 0 | 144 |
| Ember carried by a fire troll or a hand of glory | 1 cell | visible | 180, 110, 50, 0 | 120 |
| Ember full carried by an ember mote | 2 cells | visible | 200, 125, 60, 0 | 135 |
| Ember glow | 2 cells | visible | 170, 60, 35, 0 | 81 |
| Faintly glowing magic item (Radiant, of Light) | 2 cells | visible | 70, 80, 105, 0 | 79 |
| You, while Branded | 3 cells | visible | 95, 105, 140, 0 | 105 |
| Brightly glowing magic item (Radiant, of Light) | 4 cells | visible | 125, 135, 175, 0 | 135 |
| You, while Lit | 6 cells | visible | 235, 235, 250, 0 | 236 |
| Spell circle, evocation (anyone stunned) | 1 cell | visible and UV | 70, 38, 16, 90 | 43 |
| Spell circle, necromancy (anyone weakened) | 1 cell | visible and UV | 48, 36, 64, 90 | 40 |
| Spell circle, abjuration (anyone blessed, glamoured, silenced) | 1 cell | visible and UV | 32, 48, 68, 90 | 46 |
| Spell circle, restoration (anyone renewing) | 1 cell | visible and UV | 66, 52, 20, 90 | 52 |
| Spell circle, transmutation (anyone hasted, barkskin, water-borne, cat-eyed, sluggish, webbed) | 1 cell | visible and UV | 30, 56, 30, 90 | 48 |
| Spell circle, enchantment (anyone bound, hexed, drowsy, pinned, frightened, transfixed) | 1 cell | visible and UV | 62, 34, 54, 90 | 41 |
| Spell circle, divination (anyone quick-sensed, seeing) | 1 cell | visible and UV | 46, 46, 54, 90 | 46 |
Light is strongest at the source and fades smoothly to nothing at the edge of its reach. Walls, closed doors, and anything else that blocks sight, such as trees and boulders, stop light. A light source in a cell that blocks sight, such as one on a closed door, gives no light at all.
Shadows come from the same rule. A pillar or a wall casts a shadow behind it, away from the light, and the cells there get none of that light.
Bounce
Surfaces reflect a little light. Lit floor and walls glow faintly into the cells next to them, in a tint that depends on the surface: a grassy meadow bounces green-yellow, water bounces blue. Bounce never crosses a wall, reaches only three cells from the surface, and is never more than about an eighth of the direct light.
Walls
A source lights a wall the way it would light a floor cell at the same distance, but only where you can see a face of the wall that the source lights. So light never seems to leak through walls.
What is only for show
Some effects look like light but never change what you can see:
- Flicker. Torches and fires flicker and drift in color, and lamps burn more calmly. Magical light (crystals, runes, fungus) holds perfectly steady. Flicker can be switched off in the settings.
- Creature shadows. Creatures, you included, cast soft shadows. They are only drawn: a creature cannot hide in another creature’s shadow, and nobody sees you any less for standing in one.
- Glow and particles. Sparks over a brazier or the glow of a rune are decoration.
- Falling rain. The drops are decoration; the clouds that dim the light are not (see Weather).
Each of these except creature shadows has its own switch in the settings, and reduced effects turns them all off. Creature shadows are always drawn.
See also: Sight and memory, Vision types, and Your lantern.