If you are a pastel painter and enjoy using sanded paper, you are undoubtedly mourning the unavailable Wallis papers. Production issues have caused a worldwide disappearance of this popular paper. Lots of pastel painters love the special edition color of Belgium Mist Wallis. Lots are trying to find a substitution and some are trying to use some type of paint to match this color on other papers.
I am lucky to have a small stash of this paper and I thought I'd try to find a paint to match too. I have several of the "Oops" paint samples from Home Depot and a few of these seem fairly close in value to Belgium Mist but not in color. I attempted to adjust these colors with some tubed acrylic paints, then thinned them with water. I wanted the paint to be thin enough to not affect the grit of the sanded paper. I got 'sorta' close in color and painted on a piece of UArt 400 and a piece of Canson Touch White.
Shown in the photo below, you also see the Belgium Mist and a small piece of Pastelmat dark grey. The Pastelmat is really close but the paper is not sanded (although it is a favorite paper of mine). After the UArt and Canson painted papers dried, I tried out the feel with some hard pastel sticks. I didn't like the texture on the Canson, but the UArt felt pretty nice. I am not sure I would bother to paint a large sheet of UArt this way, but it might be good for smaller paintings. I'm not certain that the exact color is important, but the value of the Belgium Mist is probably what makes it so popular, as it works so well as a background to both dark and light pastel applications.
Because I wanted to use UArt sanded paper for my next project, and I wanted to underpaint some areas with a dark wash, I decided to try her technique for "scene suggestion". I cut a small (3"x10") piece of UArt in roughly the shape I plan for the larger painting. (I found a thin shaped frame at the thrift shop I wanted to use for a painting.)
I did a quick pencil sketch, fixed that, and then used black and white acrylic gesso thinned down (instead of acrylic tube paint) to paint in the major lights/darks. I setup the painted paper to take a photo and the white ran a bit! But it really didn't matter. I then quickly filled in some of the color with hard pastels. I think this will work quite nicely for the larger piece - you've got a sneak peek to a suggestion of that painting!