Fold-forming is a technique of metalworking whereby metal is folded, repeatedly forged and annealed, and unfolded; at which stage it generally has a dramatic new three-dimensional form.
The technique was invented in the late 1980s by Charles Lewton-Brain, an English-born goldsmith who lived and studied in Tanzania, the United States, and Germany before moving to Canada. Outside of the Industrial Revolution, the method represents the first major innovation in metalworking in thousands of years. It can best be described as a combination of origami and traditional metalworking. By 1991, Lewton-Brain was winning awards for the technique and in 1997 workshops demonstrating the technique were at the core of the "Touch the Future" portion of the JCK International Jewelry Show in Orlando, Florida.
Hundreds of folds have now been categorized, and techniques now include use of traditional forging tools, rolling mills, and embedding wire and other objects into the folds.