A method of making a fiberoptic light guide utilizes a hollow glass cladding blackened by chemical reduction. The cladding has a predetermined lead content and is heated to an elevated temperature in an atmosphere of substantially 100% hydrogen gas in a furnace. The blackening step is accomplished before or after a bundle of optic fibers is inserted within the cladding and is drawn to produce a fused fiberoptic rod. The blackening step provides the cladding with a black opaque nature that inhibits the transmission of light transversely through the cladding.