Stretching and Straining (Canvas, That Is)
An artist can get a bit spoiled by continuously painting on pre-primed panels because it is easy to forget the steps needed to prepare a painting surface from raw materials. It has been longer than I can remember when I prepared a stretched canvas from scratch. However, I got reacquainted with this process quickly when I embarked on assembling a 4 foot by 5 foot and 3 foot by 4 foot (121.9 cm by 1.524 cm and 91.4 cm by 121.9 cm)
Just to make it a bit harder, I also made my own strainer bars. The only things I didn’t do was to fell the trees to provide the wood or grow the cotton for the canvas, although it felt like I did.
After trying all sorts of experiments, I came up with using wood that is 2 in. by ¾ in. thick and attaching screen door molding around the perimeter of the strainer to raise the canvas off of the flat surface of the strainer. This eliminates telegraphing the outlines of the support elements beneath the canvas. So after long hours of careful measuring and safely cutting wood on my table saw, the mitered parts were biscuit joined and glued together. The last component to add was the screen door molding around the edge of the strainer.
My canvas preparation is very “old school.” I cut cotton canvas about 1 foot longer than the size of the strainer to accommodate shrinkage. I wash the canvas to remove the factory sizing. I fill a laundry sink with warm water and add a generous amount of Orvus WA Paste* to the warm water. After washing, the cotton I rinse it with a garden hose outside, run it through a rinse and spin cycle in a washing machine and then dry it for around 30 minutes in a dryer.
The amount of sizing in the wash water was significant. The waste water was medium amber in color. Ironing the wrinkles is probably the most tedious part of the process. However, the canvas is clean, soft and the weave tightens. (* Please note, If you purchase Orvus online from a tack shop, you will be inundated with magazines selling expensive gear for horses. This multi-purpose soap is used to bathe horses, dogs AND quilters use it to wash fabric. The soap rinses out well to mitigate any residue.)
Finding a large enough area to attach the canvas to the strainer is a chore.
I use the standard method of attaching the canvas at the middle of the 4 sides and then work my way towards the corners switching to the opposing side of the strainer after applying 3 staples. Sore hands from pulling with canvas pliers and stapling convinced me to purchase an electric stapler. The one that also shoots 15 mm brads as well.
After 2 coats of PVA sizing, I let the canvas dry thoroughly. I apply a very slightly thinned coat of acrylic primer taking care to saturate the surface a best as possible. After sufficient drying, I apply a second coat that I tint with an earth color to serve as an indicator to show me anywhere I may have missed. The initial white coat showing through tells me where I may have been too stingy with my second priming. I end with another white layer for a total of 3 layers. The white layer allows me to select whatever oil color imprematura I wish to apply to tone the surface in preparation for laying in my paint.
Pinholes: As discussed in the last SoC essay, infiltration of oil into the substrate is the focus of why priming needs to be carefully done. Despite my care in priming, I noticed that pinholes form on the surface in a few places. It is easy to see how this happens. The primer is very viscous. The canvas is a bumpy surface that can thwart having the thick primer saturate the “valleys” formed where the warp and weft intersect. Acrylic primer is prone to riding on the surface of the canvas but thorough and vigorous brushing forces the primer down into the weave to form a continuous layer to protect the canvas from oil penetration.
I will be patient and let the canvas shed any residual water before laying in my first course of paint. However, I will grid the painting at 6-inch intervals and lay out where compositional elements will go.
Syntax of Color