A few months ago, I was at the local photo shop, browsing the used darkroom equipment and talking to my son about developing 4x5. The salesman came over and we started talking. He asked if we developed other formats besides 4x5, and I told him that I mostly did 120 in SS Kinderman tanks. So he hands me a Jobo Multitank2 (#2523) and says that I should try it for 4x5... that I could load it in the changing bag (which I confess is very easy to do) and then develop the film like a regular daylight tank. Sounds attractive. So I finally got around to trying it out. I found an old plastic rear lens cap that fits snuggly over the opening where the gear is. I loaded it with 4 sheets of film and proceeded to develop them using it like a daylight tank. Lo & behold! It is not light proof when used vertically like a daylight tank - - or, at least, the one I have isn't. The lid was snapped on tight. But when I examined the reel closely, there are 2 small holes - - more like slits - - in the side of the center column of the reel which I assume let the light in while pouring in chemicals and are probably really there for good chemical circulation when used on the machine. I'm guessing that when used on it side mounted on the machine, those slits are not a problem. So my questions are simple: Should this have worked? Or was this well-intentioned salesman just stringing me along? If I melt some plastic over the 2 slits, do I need to worry about other places that might leak light? I have to say that doing 8 4x5 sheets in daylight is very attractive and it is very easy to load. Thanks for any insight.