The three soft, dark pencils that I purchased are the Prismacolor Ebony, the General's Carbon Sketch, and the Derwent 9B Graphic. The top image was done with the Ebony, the middle with the General, and the bottom with the 9B Graphic. The General is the softest and darkest, but it smudges badly requiring fixing. I usually only want to carry a pencil, a tiny sharpener, and pad when I go walking. The 9B Graphic is soft but not very dark. A lot depends upon the paper, I know. For this series, I am using a small Strathmore 400 series Sketch pad. The Ebony is dark and doesn't smudge. I will try just the Prismacolor Ebony for now. I just have to avoid the temptation to keep adding tonal values.
In the catalog for the Bonnard exhibition at Giverny, Bonnard in Normandy, Laurie Hurwitz writes, "Filled with doubts, the artist confronted his uncertainties by concentrating on drawings. 'I draw incessantly,' he wrote 'and after drawing comes composition which must act as a balance. A well-composed painting is half finished.'"