While for some bulbs, an intact glass envelope is not a barrier to successful nondestructive evaluation of the filament characteristics, the construction of others, particularly sealed beam headlights, is not conducive to unobstructed visual and microscopic examination. Standard laboratory procedure for examining a lamp bulb with an intact glass envelope is the potentially dangerous practice of thermally or mechanically breaching and removing the envelope. This article describes a newly developed, noninvasive procedure to evaluate filaments in bulbs with intact glass envelopes, which combines X-radiography with both static and dynamic electrical continuity measurements. The only safety equipment required is a radiation monitor. 6 figures