If the store-bought colour is too bright as it is, you can apply a glaze to tone it down.
You'll need a tape measure; 20-by-30-inch sheets of tissue paper; mild dishwashing detergent; matte Mod-Podge; a foam wallpaper roller; a 7-inch roller tray; a 4-inch, soft-bristle flat paintbrush; and clear latex gloves. If you want to tone down the colour with a tinted glaze, you'll also need universal tint in a burnt umber; 1 quart oil-based glaze; an edging brush; a container in wich to mix the glaze; several sheets of clear acetate or plastic for testing the glaze color and effect on the walls; and a 4-inch natural bristle staining brush.
1 To determine the amount of tissue paper needed per wall, multiply the wall's height times the width in inches. Now divide this number by the number of square inches in one sheet of tissue paper. Triple that amount so you'll have enough for a second, overlapping layer, cutoffs, and boo-boos. Here, the calculations for a wall measuring 8 1/2 feet high by 10 feet wide, or 102 inches by 120 inches: Wall: 102 x 120 = 12,240 square inches total. Tissue paper: 20 inches by 30 inches per sheet. 12, 240 / 600 = 20.4. Round that up to 21, multiply by 3, and presto - you'll need 63 sheets to cover the wall.
2 You can cut the sheets of tissue into smaller squares and rectangles, like I did, or leave them as they are. The smaller sizes are easier to handle, but the cutting and application is more labor intensive.