if you scan B/W use RGB mode instead of gray scale, you get some color tint depoend on scanner, software, density of the negative...it not because negatives have litlle green colour (400 ASA Ilford b/w film),green on neg should become red on print.
it not wrong scan B/W use RGB mode, actual, if you know how to manage Hue and Saturation while you're scanning, you can gain more detail and contrast control than use gray scale mode. after you finished the scan and open with photo editing program you have convert the RGB to Gray to get B/W photo. use PhotoShop?