Abstract: A dust free container is disclosed herein for storing an optical membrane assembly such as a pellicle after the assembly is manufactured but before the latter is placed into use. The optical membrane assembly is one which includes a circumferential frame having a front side and a back side and an optical membrane mounted to and extending across the entire extent of the frame. The container, which is preferably black in color along substantially its entire extent, includes a base member defining an upwardly facing circumferential shoulder. This shoulder supports the front side of the circumferential frame forming part of the overall membrane assembly along its entire extent such that the front face of the optical membrane is maintained in spatial relationship with the rest of the base member.