The transmission vs surface density (thickness) relationship has been determined for thin antimony films. Data are given for both white and monochromatic light (4500, 5380, and 6650 Å). The results are more accurate than those usually tabulated since the surface densities were determined directly from these films. These films were primarily evaporated from evenly coated thin nickel rings, giving films of extreme uniformity. Holland's surface density distribution for films from ring evaporators was found to give an accurate representation of these films. Films of the largest area of constant thickness were produced when the ratio of the evaporation distance to the ring's inner radius was approximately 1.3.