It may be just while the under painting dries so we can start layering up? and In the case of Acrylics that may only be for a few hours or overnight. But in the case of Oils then we have a real problem as this can take weeks or even months (depending upon how it is painted ) to dry properly, Many artists often work on several oil paintings at a time, mostly to avoid twiddling thumbs until a layer of paint is dry enough to paint over.
Varnishing a Finished Painting
We have a similar problem with finished paintings that are awaiting varnishing, this can take several months in some cases before you dare apply varnish. Not only do you need to store it but also keep it free from dust.
So how do we hang a canvas temporarily?
Well in my small summerhouse studio space is an issue as I also store lengths of picture moulding. To address all these issues I have some angle shelf brackets that hold the moulding lengths in place just under the eve of the shed roof. Below these I strung 2 lengths of wire 10 inches apart that allow me to hang 2 rows of canvases. You can see the wires in action in the main pic above.
But how to hang the canvas without marking the paint or the wooden support. In my case I use the metal plates used to blank slots in the back of computers. These little plates a soft enough to bend into the shapes shown in the following images.
The plates bought off eBay for a few pounds easily slide up between the canvas and the wooden stretcher bars and can be hooked over the wires to let the canvas hang and allow air to circulate. An easy and very inexpensive solution for me and I can store up to 8 at a time. I also have curtain wire in front of all this with 2 white shower curtain that I can pull across to protect from dust and paint plashes.