Blacksmiths work primarily with wrought iron and steel. The "black" in "blacksmith" refers to the black fire scale, a layer of oxides that forms on the surface of the metal during heating. The word "smith" derives from an old word, "smite" (to hit). Thus, a blacksmith is a person who hits black metal.^[1]
Blacksmiths work by heating pieces of wrought iron or steel, until the metal becomes soft enough to be shaped with hand tools, such as a hammer, anvil and chisel. Heating is accomplished by the use of a forge fueled by propane, natural gas, coal, charcoal, coke or oil.
Some modern blacksmiths may also employ an oxyacetylene or similar blowtorch for more localized heating. Induction heating methods are gaining popularity among modern blacksmiths.
Color is important for indicating the temperature and workability of the metal: As iron is heated to increasing temperatures, it first glows red, then orange, yellow, and finally white. The ideal heat for most forging is the bright yellow-orange color appropriately known as a "forging heat". Because they must be able to see the glowing color of the metal, some blacksmiths work in dim, low-light conditions. Most work in well-lit conditions. The key is to have consistent lighting which is not too bright. Direct sunlight obscures the colors.
The techniques of smithing may be roughly divided into forging (sometimes called "sculpting"), welding, heat treating, and finishing.