It would help if you first filtered the light with the orange mask built into colour negative film. A blank (clear) piece of colour negative film sandwiched with your black and white negative would do the trick.
Is it possible to put this in a different portion of the light path, such that the extra piece of film does not add any extra dust to the print? I was thinking perhaps of using a larger piece, like a piece of 120 film below the lens, perhaps?
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh