Photographic film cassette and light-trapping method for the same

A photographic film cassette including a spool with photographic film wound thereon, a cassette shell for containing said spool rotatably, and a pair of light-trapping ribbons attached to an inside of a photographic film passageway of said cassette shell for preventing light from entering said cassette shell through said passageway, rotation of said spool in an unwinding direction causing a leader of said photographic film to advance outward from said passageway between said pair of ribbons, wherein:

• said ribbons are a warp pile fabric woven from warp threads, weft threads and warp pile threads, and being constructed such that a first warp thread of one pair of warp threads juxtaposed to one pile thread passes above and across a weft thread, said one pile thread passing below and across said weft thread, and that a second warp thread of said one pair of warp threads passes below and across said weft thread;
• said pile threads being slanted in a predetermined direction relative to a ground constituted of said warp and weft threads, which is towards said second warp thread and along said weft threads;
• and
• said ribbons being oriented so that said pile threads slant toward and outside of said cassette shell.