look for the union label‘ is an online ‘celebration of union logos and emblems’ compiled by jeff rosen and susan parker sherwood of the labor archives and research center at san francisco state university. the site chronicles workers union labels of the USA and provides insight into some of their origins and applications.

USA workers union labels archive

‘the use of emblems to denote workers in a particular craft predates the advent of the modern union label by many centuries.  craft guilds, which had become widespread as a form of organization by the 1400s, often decorated their halls and seals with a visual symbol of either the tools or the product of their art – or both. the elements that once graced the coat of arms of a craft guild were incorporated into the mark of a labor union.’ more

via manystuff