I'm looking for some very thin tough black tape to repair my Mido 8x10 holders
The normal dark slide tape won't do the job.
First, unlike regular film holders, I'm fairly sure it does need to be light tight.
Secondly it needs to be very thin - the bottom flap hinge that the tape forms is on the top suface of the darkslide, not the end. Thick (i.e. "normal" thickness) tape causes a slight ridge which will probably let in light once it's placed in the clamshell for use. (e.g. normal gaffer/duct tape is too thick)
It needs to be 1/2" wide - I'm thinking maybe some kind of black mylar/metalized tape maybe? I've hunted through all the (few) auto repair/bodywork/ electronics/hardware stores in town - nothing that fits the bill.