Since making their first appearances around 7000-2000 BCE, we’ve been going to some of the greatest lengths to bring out the best and brightest in fabric dyes. Mordants (metal salts) were the earliest forms of fabric dyes additives. Used to prevent colors from washing or light-bleaching out, fabric dye additives (mordants) were applied during the dyeing process. The most common forms of dye additives were aluminum and iron salts. Eventually, copper, tin, and chrome became some of the most widely-used fabric dye additives. Today, additives are as common to the dyeing process as fabric dyes themselves.