Lithographic tusche in stick form by Charbonnel.
Mixing can be made with water (distilled water ideally), turpentine or petroleum solvent in a dish. Warming the dish makes the process easier.
Tusche mixed with water flows easily and dries slowly.
Tusche mixed with turpentine is more viscious and penetrates deeplier in the stone. The image so produced is deeplier seated and more resistant to etching. The image prints also darker than the drawing on the stone.