Hi, I've finally managed to get hold of an developing tank for my 2 1/4 x 3 1/4 sheet film - it's an Envoy Plate Developing Tank which has holders for dealing with the sheet film. But how do I use it? More specifically is this item light-tight (looks like it is) and what is the best method of agitation for the film inside? Presumably one just lifts up one side an inch or so and gently puts it down, then lifts up the other side (and so on). Am I close? Cheers, Dave.