Storing portraits

[Sylvia Castellanos]

Before including this post here, I looked around to find an appropriate category, but really found none. If the moderators feel it belongs elsewhere, please feel free to move it.

I've recently rented a storage unit in a building with temperature and humidity control, and had shelving built to maximize the use of the space. At present I have all my works stored vertically on these shelves divided by large pieces of cardboard. My question is whether each painting should be covered in some way, either wrapped in some sort of large sheet or a large plastic bag, or if they are better without individual protection.

Thanks in advance for your feedback.