I think atomic energy provides the best light for this purpose.
I suggest a natural source, like the sun.
The alternative would be so messy.
Here's a link which might be helpful, and importantly, ammusing.
A community dedicated to Lugers, Central Powers, Axis, Allied and related WW-I and WW-II pistols by their scholars, collectors, owners and enthusiasts. Come join the discussion about the history, technology and extraordinary background associated with these design masterpieces.