System and method for controlling light in a facility

A system for controlling light in a facility having a facility frame, a first facility end, a second facility end, a facility floor and opaque/reflective facility walls, the system comprising:

• at least one rail longitudinally affixable to an inner portion of the facility frame between the first facility end and the second facility end and elevated by a rail-height above the facility floor;
• and
• at least one opaque/reflective covering tightly and opaquely affixable to the inner portion of the facility frame and elevated by a cover-height above the facility floor in a first plane that faces the facility floor and slidably connectable to the at least one rail, the at least one opaque/reflective covering being extendable along the at least one rail between a first covering position and a second covering position to opaquely cover respective at least one longitudinal section of the facility in the first plane when in the second covering position, without substantially covering the opaque/reflective facility walls, to thereby prevent light transmittance into the facility.