|From a site that sells reproductions.|
Candles were expensive—depending upon what kind of candles they were, that is. A chandler, or candle-maker, produced one of two types: tallow or wax candles.
Tallow candles were made by rendering animal fat and dipping the wick (made from a braided string) into it. The fat would cool and harden, and you would then dip the result into the melted tallow again, pulling it out when a new layer of fat was deposited and before the original layer re-melted.
Tallow candles were cheaper than beeswax candles. Many households had their own livestock and could produce their own fat. To make a lot of tallow candles, however, required a lot of tallow. Tallow was also used for soap, and the household's animal fat had to be divided up between candle-making and soap-making. Professional tallow chandlers would procure large amounts of tallow by dealing with butchers, and could produce and sell tallow candles in large quantities.
Tallow candles were a yellowish color because of their source material, and although they provided light, they also produced an unpleasant odor. Not only that, they were a draw for rodents, who loved to gnaw on what was essentially congealed animal fat. For that reason, those who could afford it would purchase candles made from beeswax.
Beeswax was more difficult to come by, since it had to come from hives. You would not want to devastate the hive by taking all its wax and causing harm to the bees, so you had to carefully harvest the wax. Wax candles were lighter in color, depending on their treatment. Initially yellowish, if the blocks of wax were left out in the sun long enough, they bleached white.
Wax candles did not give off the odor of burning animal fat, and were much preferred by churches and wealthier households. It was possible to supplement the wax with some tallow. Later laws put an upper limit to the amount of tallow that was allowed in wax candles, however.