The Arcetri Infrared Instrumental Group is involved in design, building and testing the Spectrograph (SPG) of the instrument. The cold spectroraph of AMBER (indicated by the acronym SPG in AMBER documentation), besides operating the spectral dispersion of incoming beams, includes the following functions: . Formation of an image of the fiber outputs at cryogenic temperature and filtering of thermal radiation from this image by means of suitable spatial filters . ...