A process obtains an aged or faded effect on garments made of protein fibers such as wool, cashmere and silk. Granules of inert materials, which are particularly light in order not to damage very fine fibers, are introduced into a tumbler. The garments were previously treated with a chemical product commonly referred to as “dye retardant” for inhibiting dyeing of the fabric. The tumbler is pre-arranged so that the chemical product does not migrate through holes or openings. Raw confectioned garments that are to be treated, such as jerseys or outerwear, are introduced into the tumbler. The garments are extracted from the tumbler at the end of migration of the chemical product for inhibiting dyeing of the outer surface of the garments by the granules and steamed in an autoclave to fix the chemical process of the product for inhibiting dyeing of the outer surface of the garments. The garments are then dyed with a specific selection of dyes that must be defined each time according to the desired result.