Around 1900, blacksmiths in Thiers, during the golden age of traditional hand forging, commonly wore the “Bleu de Travail” work vest. This durable and practical garment, exposed daily to carbon dust, fire, and cooling water during their labor, gradually developed a distinctive aged patina and layered coloration. It not only bore the traces of industrial work but also became a representative garment embodying both craftsmanship and utilitarian design of that era.