An Acid is a corrosive liquid. Acids occur naturally, for example in the human digestive system, and in lemons. Other acids are man-made. Acids vary in their corrosive strength, whilst some are weak and can be used in cooking, others are extremely dangerous and will dissolve metal and cause severe burns to human skin.

WARNING: Acids are an irritant to humans; skin contact should be avoided, skin and eyes should be protected when using acids.

Art Technique: Etching
Acid is commonly used by an artist during Printmaking prior to printing an etching. Acid is used to deep-etch an etched metal plate. By soaking the etched plate in an acid bath the etched area (scratched surface) on the plate will be eroded further. Acid-etching allows the artist to achieve a greater number of prints from a single etching plate before the plate deteriorates and the print quality therefore deteriorates too.