A modified synthetic polymer filament and multifilament yarn of polyamide or polyester filament containing a carbon black polymer additive, and fabrics from these yarns, are disclosed. These melt spun filaments are especially well-suited for use in garments and equipment where a modified Near Infrared Reflectance (NIR) signature is desired. The yarn and fabrics made from this yarn may be advantageously dyed or printed to provide a camouflage fabric for use in desert sand dominated environments, urban environments and multi-terrain environments.