Drawing involves the use of lines and clusters of lines called values. Lines and values often merge spontaneously as you draw, one springing from another in the same stroke. The better you understand the range of expression and working qualities of your pencil or pen, the broader your palette of artistic options are when you create.

A line is a flowing stroke of your pencil that defines an edge in the image you are drawing. Value is the gradation of grays you use to define the mass, form, light, and design of your drawing.

FYI Art Talk and Semantic Bad Habits: The terms "tone" and "shade" are often used interchangably with "value". Tone is a color term used when gray is mixed with a pure color. You then achieve a tone. Shade is another color term used when black is mixed with a a pure color. You then achieve a shade. If you add white to a pure color you get a tint. You can also take any of these colors and relate their lightness or darkness to the grays found in the 10-value scale irregardless of their hue.

I did use the term tone for years for describing black and white drawing. Whoops. When you strip color from the picture, you should also strip the language of color from your jargon. I'll use the term "value" when talking about a gray created by drawing in black in white. I'll even use the term "shading" to describe making the right values to bring out forms and shapes because it also means "relative darkness" and "cast shadow."