Abstract: The process for producing patterns on ground dye colored textile fiber pile substrates, particularly wherein the pile fibers are in the form of yarns comprised predominantly of polyamide fiber, and wherein at least some of the ground dye component is at least partially color dischargeable and selected from vat, reactive, direct, acid, premetallized or mordant dyes, the process comprising contacting selected portions of the colored pile fibers with a reducing system which optionally can contain one or more reduction resistant dye or pigment materials for in situ coloring of the substrates, the contacting being characterized by jet forcing the reducing system interstitially of the pile fibers to deposit the reducing system thereon substantially below the surface thereof, and to effect the color discharge of at least a portion of the ground dye component.