I want to shoot my first double exposure.
My plan is to shoot through a whole roll twice (because my film release button is a bit janky and shooting twice without advancing the film doesn't quite work and gives results like picrel). Has anyone done that? I was thinking of marking putting some markers on the film so I can load it the exact same way the second time. I've seen people do it online and apparently it worked, though the 60 year old guy at the lab who I talked to about this said I'm crazy and it will never work.
Also I'm assuming I want half the amount of light on each exposure, right? So if I use 200 ISO film and set the ISO for my lightmeter one stop lower to 100 I should be good to go, right?