My last two still life set-ups have had large shadows cast on the back wall. The transition between these shadows and the lit areas can be very difficult to paint. Typically, I use a dark glaze for my shadows. I paint the background, allow it to dry, and then glaze the dark shadow over it, blending the edges of the glaze with a cotton pad to achieve a smooth transition. If the underpainting is smooth enough, this works just fine. I used this method successfully in my "Renaissance Tray’ painting, top painting above. However, if too many dried brush strokes catch the glaze from underneath, an uneven appearance results. When this happens, I’m forced to try to blend the edge either while the glaze is still wet, or after it dries. There are problems with both methods. Working with a wet, dark glaze can be difficult, especially when I’m trying to blend it with a lighter area. To blend it, I must first add some new, fresh paint to the dried background, and work this wet paint into the dark, glazed area. The white in this light area blends with the colors of the dark glaze, which usually contains ultramarine blue. This blending results in an area of light blue at the transition instead of the smooth transition from the color of the background to the dark neutral of the glaze. This is not the effect I wanted!  If I wait for the glaze to dry, I have other difficulties. The hard edge must be smoothed with a transitional area of fresh paint that must be worked into both the shadow on one side and the light on the other. Blending fresh paint into the light area isn’t hard, because both contain white and are opaque (and reflect light the same way). This same paint, however, doesn’t blend well with the dried glaze, which because of the glaze medium blended with it, is glassy and transparent (and reflects light in a very different way!). I’m having this problem in "Golden Goblet and Blue Vase,’ second painting, above, which I’m currently working on. The shadow cast on the back wall has a very uneven edge and my attempts to smooth it out haven’t been very successful. If all else fails, I could repaint the entire back wall, let it dry, and then try glazing the shadow again. I hope it doesn’t come to that! By the way, there is a third option, which is painting the shadow at the same time as the wall, in solid paint, using no glaze, and simply blending wet-in-wet. I haven’t tried that because I love the way a glaze mimics the look of an actual shadow.