GAGB Chelsea Colour Filter 1990s

This filter represents an updated version of the 1970s GAGB Chelsea Colour Filter, housed in a later case material that appears less prone to yellowing. As the Gemmological Association of Great Britain adopted the name Gem-A around 2001, this unit is most plausibly dated to the 1990s.

The precise manufacturing date of this Chelsea Filter has not been determined.

This object is part of the museum archives; no examples are currently available for sale.