Here is the situation: I will be hanging a large drawing on heavyweight black paper(approx. 4'H x 10'W) in a gym. I am concerned about humidity and water resistance. This "mural" will also need to be rolled up prior to and after the installation. Does anyone know or recommend a fixative or sealant that would provide good protection in that environment, not harm the longevity of the piece or create hazing, and would be flexible enough to take being rolled up? I would appreciate the advice. Thank you.

I am sure you have already completed this project and most likely came up with the answer that best suited your problem. But if you haven't, I find that the best solution to new problems is doing a test. I've fixed many drawings (pencil/charcoal) with Blair Spray Fixitive, which because of it's very light solvent based medium it is either absorbed into the paper or evaporates. This would be the best solution for paper that is being rolled up, as anything heavier (like clear acrylic sprays) may crack depending on how tight you roll the paper.

One note of caution: Blair Fixitive has toxic solvents so good ventilation is a must when spraying.