  Results of absolute light output measurements on strontium and barium
fluoride doped with PrF$_3$ and CeF$_3$ are presented and compared with
scintillators having well-known light output (NaI-Tl, CsI-Tl, BGO). For pure
SrF$_2$ crystal we obtain a value of about 28600 photons/MeV.
