I use different materials for murals, depending on the size needed, and the surface where they are intended. MDO plywood for rigid panels are great for mounting on exterior walls. Canvas or muslin is suitable when the work is best performed in the studio, and may be rolled and shipped for installation on site.
This is a description of preparing muslin that measures approx 120 inches (10ft) x 192 inches (16ft), as that is the size of my wall. The final mural size will measure approx 6 to 8 inches smaller, after trimming.
There are a several sources of this material, Rosebrand and i Weiss are a couple of excellent theatrical supply houses. For smaller murals, narrower widths are easily available from regular fabric suppliers, and you can save on shipping.
As well as the large size possible with theatrical muslin, I prefer painting on a firm surface, unlike on artist stretchers which are a bit bouncy. Using large wood stretchers are fine, when you have room, and not a large enough flat wall. Canvas is best over stretchers, the muslin will be too thin in that case.
About this wall; homasote cut to fit in 2x4 frames in ... ceiling height is 9ft 6inches, wall is 16 ft wide. The final mural will be trimmed to about 9ft x 15 ft.
All the homasote panels in place. I like homasote because its very easy to staple into, or use push pins, and easy to mend. Its a little lumpy, and drywall is a smoother harder alternative, if a really smooth surface is crucial to you.
Important to smooth seams with tape and joint compound... challenging due to the bumpy surface of the homasote.
Tape a layer of thin polyethlene sheeting in place, as smoothly as possible over the wall.
After the plastic is up, a charcoal line is snapped across the top of the wall, to be the guide in tacking the top edge of the muslin, starting in the center. Tack the center top, then the center bottom, then the corners. The top edge of the muslin is actually perfectly level.. I photoshopped two photos together here which distorts the angles a bit.
For a very large piece of material, using a plumb helps ensure your stretching evenly. The plumb is hanging down the center of the canvas.I snap a charcoal line that will be easily brushed off.. to help guide in the even stretching of this large mural. If I pull to hard, or unevenly while I staple the sides, I can see easily the crooked chalk line.
Working solo to stretch the muslin, requires many trips up and down the ladders.
the muslin is stretched, but not too tightly. Too tight at this stage and your muslin might tear or pull out. The wrinkles will disappear when the many coats of priming are applied.
The following steps are what I do to prime, though you can skip the step with the alkyd.. I learned that step from Pierre Finkelstein, its a lot of work. You could skip it, and do a couple more coats with undiluted primer, if you don't want the trouble of degreasing.
Prep, 1st ct , Fresh Start / Benjamin Moore primer / w 30% water,
2nd ct , " / 15% water /
3rd ct, " / 5% water
4th & 5th cts, Oil based/ BM Dulamel eggshell, or other alkyd primer (light sand between cts)
Then degrease whole thing with whiting. Make sure you get all the whiting off; wipe with a damp sponge till you see NO whiting on the sponge.
Then paint mural with acrylics.
There will be virtually no shrinkage after cutting mural down.