Through this thaumaturgical ritual, the practitioner can pour a special pitch-black oil into a pool of water and make the water solid black. The water will become completely opaque but it has no other effect. It will remain black until the effect is dispelled, the water evaporates, or the water is diluted with a larger body of normal water.
One pint covers a small swimming pool size area. It last for a week and a large amount can be prepared at one time.