The Hadal Zone, named for the Greek underworld, Hades, is the deepest oceanic zone, below the Sunlight Zone, the Twilight Zone, the Midnight Zone and the Abyss. Hadal blue and hadal green are the deepest colours achievable through reactive dyeing, darker than any natural dye. As with natural dyeing, though, the whole garment is dyed after sewing, showing subtle variations in tone and depth between different fabrics and garment constructions.