Light color and black/white film testing

[JeffD]

I would like to conduct some indoor film tests in which a grey card is illuminated by a lamp, and film exposed and densities checked.

I understand that modern black and white films are somewhat pan chromatic, or, supposedly the lamp light "color" used to illuminate the grety card shouldn't matter much, or does it?

How much variation might I have from typical tungsten light, compared to outdoor light in regards to densities registered on film from the same brightness levels?

If there is a significant variation, is there an inexpensive, readily available lamp bulb I could purchase that might make any differences negligable from a practical photography perspective?