Note: this does not apply to the Light attribute of Projectiles.
The Light attribute was added to the tConfig Tile class in version 0.27.1. Its purpose is to specify the amount and color of light emitted by a custom tile in the .ini file of that tile.The format of the attribute is
The values of the attribute are interpreted as float values representing the RGB values of the color of the light emitted; integer values may be specified but may have unintended results (see Examples below). They are intended to be in the range 0.0 to 1.0, with light=1.0,1.0,1.0 representing white light that approximates the amount of light emitted by a Torch from vanilla Terraria. light=0.0,0.0,0.0 is effectively no light at all. Values greater than 1.0 make the area of illumination bigger (brighter), values less than 1.0 make the area of illumination smaller (dimmer).
To convert RGB values from 0-255 format, simply divide each value by 255 and use the (rounded float) result. Example:
255,75,175 -> 1.0,0.29,0.69
The lighted=True is required to for the tile to actually emit light; without it, or set to False, the tile will not be lighted. The same is true if the lighted attribute is specified but the light attribute is not. (When an .ini file for a vanilla Terraria tile contains lighted=True, it means the tile emits light as specified within the vanilla game code.)