See: http://www.kodak.com/global/en/consu...cts/pdf/k4.pdf

First, let me apologize in advance for any offense this may cause to the OP or any commenter, but this is an on-going debate.

Please obtain, test, and use a proper safelight. There have been many threads on this forum over the years with similar things. There have been numerous augmentative posts. People will spend money on cameras, film, paper, chemistry, tanks, trays and enlargers, the best lenses, but won't buy a proper safelight. If your talented father wishes to make you a lamp, that's great; but you and he do not need to re-invent a critical piece of darkroom equipment that is readily available.

From the Kodak pub cited above:

​IMPORTANT FACTS ABOUT SAFELIGHTS
> No safelight provides completely safe exposure for an indefinite period of time.
> Safelight filters are designed for specific types of paper and film.
> Safelight filters fade with use.
> Poor safelight conditions can produce a loss in photographic quality before actual fogging is visible.
> Many photographic materials require handling in TOTAL darkness.

Therefore, you should
Follow all safelight recommendations for your paper or film.
See product instructions for recommended safelight filter, bulb wattage, and minimum safelight distance.
Test your safelight conditions regularly.
Replace your safelight filters when necessary.


And as has already been mentioned, with any safelight, testing is necessary. The procedure is also outlined in this (and other) publications. Good luck!