When I traveled to Bellagio and Varenna, one of the things that struck me about the landscape was the dramatic cloud formations that settled over these little lake towns. Possibly this is due to the altitude, or the difference in altitude between the lake and the surrounding mountains. OR, it could have just been my timing. In any event, while they were very beautiful and created spectacular displays, they also made it pretty tricky to sketch/paint en plein air because the daggone light kept changing from minute to minute. In the studio, of course all of that is much easier to control, and I get to celebrate the beauty of the clouds without at the same time cursing the inconvenience of them ;-). After I sketch in my composition, my most common approach to landscape painting is to lay in the sky and the far distance. Since the sky contains my light source, the highlighted sides of the clouds will hold some of the lightest values in the painting. Probably the only other things that approach this high value is the light bouncing off of the white painted boats.
I am not sure if it's evident in this photo, but I have used an array of colors(cad orange, cad red light, alizarin permanent, ultramarine and sevres blue) to tint the clouds. The blue sky is a combo of ultramarine, sevres blue, and white.
Next distant mountains progressively deepen in value, but they are still very cool in temperature, so that they will sit back behind what's to come in the foreground. After evaluating my composition further, I decided to raise the distant horizon line, so as to push those cliffs back a bit more, in relation to the foreground town.
After I get the painting a little further on, I may come back and tweak what I've done here. But for now it's time to address the water and the heart of the matter; the town of Varenna.