Thanks for all the replies, I never imagined so many people would put so much thought into this and I really appreciate it!
Regarding some of the questions/concerns the photographer is a hobbyist that likes to do scenery photos and candid shots of people around town, I don't imagine him as someone that would have studio equipment. This character first got into developing photos because he didn't want people at a lab seeing the pictures he was taking because they were kind of creepy/stalkery and he lives in a smallish town. The girl he was stalking was dating his brother but then moved away for a couple years and he got more interested in photography in general. But when the girl moves back in town he offers to let her move in to his spare bedroom that he uses as his dark room. She doesn't know he is obsessed with her, she just thinks of him as her ex's innocent little brother and she agrees to move in with him.
So, even though he doesn't need much space he gets a storage unit because he doesn't want her to see all the pictures he has of her from years and years ago. While his dark room supplies are in the unit, that's not really why he got it, he got it so she didn't find his secret stash of creepy pictures.
Uh, sorry if this story kind of paints photographers in a negative light.