Options

Everything has sensible defaults. Client options live in the in-game config screen, the config file, and Sodium's Video Settings.

Client

Option	Default	What it does
mode	LAMB	Rendering backend: LAMB, VEIL or OFF. A mode whose mod is absent lights nothing and says so on screen; your choice is kept, so installing the mod later just works.
luminanceMultiplier	1.0	Overall brightness, up to 2.0.
updateInterval	0	Milliseconds between updates of the light a build casts outward. 0 is every tick, smoothest; higher costs less.
worldUpdateInterval	0	The same, for light cast back onto a build.
showStatusOverlay	on	Show a short message in the bottom-right when something needs attention (no backend installed, a backend missing, a feature that disabled itself). Click its x to dismiss. Everything shown also goes to the log.
enableContraptionDynamicLight	on	A Create contraption casts the light it carries.
enableSubLevelDynamicLight	on	A Sable sub-level casts the light it carries, including a carried beacon's beam.
enableWorldToContraptionLambLight	on	World light shines onto Create contraptions. Needs Create's Flywheel backend.
enableWorldToSubLevelLambLight	on	World light shines onto Sable sub-levels, dynamic sources and static blocks alike.
enableWorldToFlywheelLight	on	World light shines onto Flywheel-rendered blocks and entities. Needs Flywheel 1.0.6+, works without Create.
enableWorldToStructureVeilLight	on	VEIL mode only: world light shines onto contraptions and sub-levels.
enableSubLevelOcclusion	on	A sealed room inside a Sable sub-level holds its light in and keeps outside light out, in both directions. Needs Sable.

Client, coloured light

Option	Default	What it does
enableColoredLight	off	Every glowing block lights the world in its own colour, and overlapping lights blend. Turns itself off while a shaderpack is loaded.
colorIntensity	1.0	How far a colour departs from white. Below 1 washes towards white, above 1 deepens, 0 leaves every light white.
colorfulCandles	on	Dyed candles glow the colour of their wax. Off gives every candle a warm flame.
deriveColorFromTexture	on	Blocks with no colour of their own take one from their texture. Off gives them a warm torch glow instead.
animatedLightColors	on	Let a resource pack give a block a colour that cycles. Off holds every such light at the average of its colours.

More on how colours are chosen in How colours work.

Client, Iris fixes

Sable sub-levels are lit incorrectly whenever Iris is installed. These restore them, and are applied by a bundled "Contraption Lights Fixes" mod that ships inside Contraption Lights and appears as its own entry in the mod list. All three need Sable, Iris and Veil installed.

Option	Default	What it does
fixSubLevelShading	on	Restore directional face shading, which otherwise looks flat and too bright. Follows the build as it tilts, with or without a shaderpack.
fixSubLevelSkyLight	on	Go dark in caves and underground instead of staying lit as if under open sky.
fixSubLevelAmbientOcclusion	on	Shade corners and recesses the way the shaderpack shades the world's, instead of washing them out and dimming glowing blocks. Only with a shaderpack loaded, and only for packs that handle ambient occlusion themselves.

Shading and sky light take effect immediately; ambient occlusion applies to sections as they rebuild.

Server

Option	Default	What it does
enableContraptionLightBlock	off	Place real light blocks as a Create contraption moves.
enableSubLevelLightBlock	off	Place real light blocks as a Sable sub-level moves.
enableSubLevelLightBlockOcclusion	on	A light inside a sealed room on a Sable sub-level places no light block in the world outside.
minLightBlockEmission	1	Only place a light block for sources at least this bright, to place fewer of them.
lightBlockMergeTolerance	1	Lights next to each other share one light block when no spot ends up more than this many light levels darker. 0 shares only where nothing gets darker.
maxLightBlockChangesPerTick	0	Most light blocks placed, changed or removed per tick in each dimension, the rest following on later ticks. 0 is no limit.

Light blocks go into air and water, and are only ever removed by the mod that placed them. Players who also run the mod with coloured light on see them in their source's colour.

Light blocks and the client mod together. Where the server's light blocks and a player's own light overlap, the brighter one wins, so a build looks the same as with either alone. Light blocks move a whole block at a time, so on a fast build they can sit slightly off the player's smoothly moving light, and each step makes the client rebuild the chunk sections around it, which costs a little frame rate with many moving lights.