Anybody know the life of the working solution? I have a liter of working solution that I've used twice in the past week, and was thinking about using it again this evening, but I'm not sure if it's still effective. I probably processed about 20 or so 8x10 sheets with it, but like it said it's also been at working strength for about 8 days(in a bottle...not tray). Will the film strip test apply for paper? I can see how long it takes for the film to clear and if it's still close to new, then it should still be good for paper as well, right?