My local Costco (which has been great with digital prints, really!) is able to process C-41 120 format roll film. I want to try a 'test' roll first.
I recall reading years ago, to test a C-41 machine processor, you use an 'unexposed' roll of film or is it a 'exposed' roll of film shot with the lens cap on. And then look at the film base for consistency, machine marks, dirt, etc.
Am I remembering correctly? Does this make sense???
I want to test their processing before I use them..