The photographic process known as Bitumen of Judea is quite possibly the oldest modern photographic technique. The technique was first used by French lithographer Nicéphore Niépce in the 1820s. In 1826, using a tarlike material that covered a pewter plate, he took a picture of the countryside near his home. The process took 42 hours. Normally soluble in oils, the bitumen hardened (probably polymerized) and became insoluble on exposure to light. Coated and exposed copper plates were thus placed in a solvent which caused the image to appear, following which the copper was etched in acid, forming a printing plate.[1]:p.14