Toshiba has teamed up with Swiss chemical company Clariant International to develop a dye that is necessary for dual-layer recordable HD-DVD discs capable of storing 30GB of data.

HD-DVD is one of two next-generation optical disc formats that are competing to replace today's DVDs. The other format is Blu-ray Disc.

In addition to developing the dye, which is used on each recording layer, the two companies say they have produced prototype dual-layer discs and verified that they work.

At present, the highest capacity HD-DVD-R discs that have been standardised are single-layer 15GB discs. The two companies have already proposed the dual-layer disc to the DVD Forum standards body with the hope that approval will come by the end of this year.

Two other formats make up the HD-DVD family. The read-only HD-DVD-ROM format will be used for pre-recorded content like movies and has already been standardised at 15GB single-layer and 30GB dual-layer.

A triple-layer version capable of storing 45GB is going through the standardisation process. There is also a rewritable format called HD-DVD-RW that has been standardised at 20GB. A future version of the rewritable disc that can hold around 32GB is under development.