Here is a suggestion for applying some drawing symbols when pencilling a canvas.
A. A clean / hard edge between an object and the background or another object and separated by distance and color.
B. An internal line, for example separating an arm across a chest of similar value and hue. Mainly used for value separation to depict internal shape and value changes.
C. An internal soft edge showing the transition of a value from light to shadow.
D. A broken or ragged edge such a coat sleeve, hair shape or tree outline.
E. A broken or ragged edge internal to D. Such as folds, seams or sky holes in trees.
F. Buildings internal outlines. Building skylines would be solid as in A. For example, window shapes, sills, mouldings.
G. Indicates a zone with an even gradient, not an edge really, a zone of transition.
H. N / A really all our A. type edges will look like this.
I. A soft edge where a form rolls gently away from the viewer.
J. A lost edge where a form rolls into shadow or to delineate the edge of similar value.
My intention here is to ease the burden when looking at a tangled mass of yellow lines on a canvas. These line symbols are easy to remember and gives more coherent picture when hovering with a loaded brush.