Looks like a fun project, but I certainly wouldn't try to extrpolate the results over different kinds of
b&w films, which in instances can be siginificantly affected by the color of light. Another problem is
that old-school bulbs for spectrophotometers and gear like this were actually "broken in" by burning
a number of hours before sale in order to reach a plateau of lumen and spectral output. The you were supposed to keep track of the number of hours of use for when to replace them, and not when
they actually burnt out.