Color Notes - Transparent Underpainting Today

I am at the Leesburg studio today.  Spent yesterday getting some pet portraits ready for clients who intend them as gifts for Christmas.  After a full day of concentrating on getting a likeness and doing fine details, I felt I needed a day just to play with color.  So today I have set up two gessoed panels side by side and started a dyptic of an autumn scene.  The photo reference is one I took down at Natural Bridge.  Since I have been extolling the virtues of transparent colors, I did an underpainting on each panel using the transparent colors, Alizarin Crimson, Sap Green, and Indian Yellow.  Unfortunately, I could not accomplish a reasonable sky without using some white and French Ultramarine Blue.  I will photograph this underpainting when I return to this studio, since (as usual) I forgot the *^%+#@  camera.