On 11/03/2019 12:32, Graham. wrote:
The last time that was an issue for me, it was the bulb for my
photographic enlarger.

There were special bulbs made for enlargers, they were designed to give
a whiter light and had the rating details printed on the side where it
wouldn't cause a problem instead of the end.

The OPs problem is different though the printing is on the white plastic
forming the base and not on the illuminated part.