Blue enlarger bulb?

One of the pieces that came with my old Kodak enlarger was a blue GE Mazda 60W bulb. Can anyone explain it's use in an enlarger? Only thing I found on a search was an early 1900's magazine article I think was explaining it was for correcting skin tones in the print with the films of that time.

Tungsten filament is no big deal these days. Maybe the lamp is a collector's item. Excluding multigrade paper, colored light has no effect in B&W printing.

If you mean a non-pearl, tungsten filament bulb with the clear glass actually being a see-thru blue colour then it is the sort of bulb that was used for "daylight" inspection, before other high CRI lighting sources became available. It would be used in a desk-light or inspection light of some sort, not in an enlarger.