yeah ..case 3 and 4 can only happened if case 1 is true. so if you zip lock bag is big enough, then maybe only slide the dark slide half way or 3/4 way down for empty holders. Then you definitely know those are not loaded (case 2). of course, by not sliding the whole dark slide down , we will increase the chances of dust getting into the film slot. so maybe your system is more dust proof.thanks for the advice... appreciated.
you see, there can be 4 case here :-
1) loaded
2) not loaded
3) exposed
4) not expose
with the black and white side on the dark-side ( flipping of exposed / unexposed film ), we can only know case 3 or case 4. Therefore, we still need another indication to know which film holder is loaded and which holder is not... haha... sounds a little bit stupid.. hahahahaha
cheers,
Billy

Previously i only have 2 film holders so it is easier to manage. Usually they r all unloaded or loaded. Now I hv more holders so I have to have a system too.