If you have been following my blogs this year, you know that I have been looking for a satisfactory way to apply watercolor to canvas. Among other things, I found that gessoed canvas does not satisfactorily hold watercolor well enough to permit layering—called glazing—an important technique when using transparent watercolors. But then I came across an alternative surfacing material, similar to gesso, that claims to hold the color better—Golden’s Absorbent Ground, in matte white.
Directions indicate that multiple coats increase absorbency, so I decided to prepare a canvas panel sectioned roughly into thirds, which I would give one, two, and three coats, respectively, of the absorbent ground to test for my own edification.
I began by coating a 16”x20” pre-gessoed canvas panel with a single coat of the ground. I dipped my brush into water before applying the ground to make it easier to spread, but otherwise did not thin it. After it had dried for several hours, I taped off the left third and coated the remainder with a second coat, which I permitted to dry overnight before applying a third coat to farthest right third. The three sections were separated with pencil lines for easier identification.
After the third coat was dry, I applied separate washes of two watercolor paints, Winsor blue, red shade (phthalocyanine blue RS, aka PB15) and burnt sienna (a synthetic iron oxide red, PR101) across all three portions of the panel. Both paints have a staining quality, which is preferable for glazing purposes. Near the top of each, I lifted out swaths through both color blocks while they were still wet, both with a dry paper towel and with a damp brush. Once the base color had dried, I applied separate glazes of both colors over each of the color blocks. Finally, I again lifted a swath from the bottom of each dried color block with a damp brush. (The illustration above shows the finished test panel.)
The following day, the effect of the absorbent ground became considerably more apparent when I ran water over the entire panel and scrubbed it with a gentle brush. Most of the color washed off, but the absorbent ground had been stained to some extent by both base coats. The more layers of ground I had used, the more stain remained, as shown below.
Conclusions: Does the absorbent ground improve paint retention? Yes!
Does the number of coats make a difference? With each successive layer of ground, the paint lifted less readily, although within a couple hours after painting, with a bit more effort and a damp brush, paint could be lifted out from even the triple application. After the paint had dried overnight, however, both paints had stained the ground and become more difficult to lift. It appears that the ground continues to absorb the stain until both the paint and the underlying ground have thoroughly dried (the ground having been remoistened by the application of wet paint). The more coats of ground there are, the longer they take to thoroughly dry, hence the more stain they absorb.
Recommendations: If glazing is to be used on (pre-gessoed) canvas, I would recommend, first, applying a minimum of three coats of the absorbent ground before beginning a painting and, second, leaving the base coat of paint to dry overnight or longer before applying subsequent glazes.
Additional notes: According to directions, “Due to the fragile, absorbent quality of the ground, finished paintings need to be protected.” Whether this protection must be in the form of glass or the equivalent or whether a spray varnish will suffice is not specified. Since my primary reason for using canvas instead of paper is to leave an exposed surface, my own inclination would be to opt for some kind of protective varnish or sealer rather than a glass or acrylic cover sheet. Such a solution might or might not be adequate—only experience will tell.