I went shopping eBay for cases for some of my enlarging lenses....OUCH ! The prices some guys want for some of those plastic cases are more than a bare lens. It's almost cheaper to buy a junk lens, just for the case.
Well that puts me back into looking for caps for these uncased lenses.
The only lens that I could "jerry rig" was the Componon-S 105mm, with the cap from a 35mm film canister. But is isn't a very good fit, the cap wants to come off easily.
Looks like I'm going to be buying a lot of caps.
You know... the heat from the lamp will cause a convection air current around the enlarger. The resulting flow of air levitates dust particles that will stick to the surface of the lens.... We certainly need a protection from this.
Right- I was just about to say that dust can indeed "fall upwards"!
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.