Can anyone tell if this is a V54 model light head, if this needs compensation filters (along with contrast filters) for b&w printing? I can't identify the model of this unit. It's old, but I don't know how old, maybe 15 years... I have the original box, but it has no info. on it or in it, and the head itself has only a sticker that says Aristo, and D-2 on it (with Aristo address etc.). Any help much appreciated. Thank you, s.