I buy the 1 litre C41 Press kits from B&H. I alwaysy mix it all, giving me enough solution to process 30 4x5 sheets. However, even when I'm working on a project it could take me 2-3 weeks to shoot 30 sheets. I accumulate film till I get the 30 to process. This is a long time to wait for feedback. I'm wondering if it is OK to split the powder in the individual envelopes to make 2 seperate batches? I don't have any experience dealing with chemicals. I'm not so worried about safety issues, but rather: 1) how do I store the unused portion? How long can I safely store it? 2) How accurate does my scale need to be? 3) Do I measure 50% of the weight out of the envelope based on the label, or do I take it all out and split into 2 equal quantities? Any other issues? Thanks.