A filter holder is disclosed comprising a base for supporting the filter holder on a work surface and a holder arm attached to the base. The holder arm comprises a base end and an indexing axis passing through the base end. A rotor is rotatably connected to the base end and comprises a plurality of filter cradles each arranged generally parallel to the indexing axis and affixed to the rotor such that, when the holder arm is in the indexing position, the rotor is rotatable about the indexing axis to move a selected filter cradle into a loading position.