Painting Technique: Working the Edges
A tortillion (pointed paper stick) and a piece of willow charcoal can be a pastel painter’s best friends when it comes to refining edges.
To complete the “touch” of a foreground object to its background, a tortillion can be used to “push” the background pastel up to the edge of the foreground object. In the example below, I take a tortillion to push the distant tree line hues (dark purple and blue shades) up to the edge of the birch tree.
But that is not the end of it! The tree itself has light wrapping around its edge: meaning that the edge of the tree is not a flat surface, but a rounded object draped in background light. To create this effect (and to remove the “flatness” of the edge of the tree, I use a willow charcoal stick to soften the edge. This way, there is less of a hard edge and the background color pushed up to the tree remains intact.
When it is time to work greater details in your painting, the tortillion and willow charcoal stick are quite useful. An alternative to both is to use a hard pastel to achieve similar effects.