The distinction between drawing and painting goes back at least to the pre-renaissance, a time when drawing was done with a very limited range of materials, in limited colors, and with little ability to mix hues. One of the distinctions of drawing still is that it is usually limited in hue - and the more hues that appear in a work, the more likely it will get labeled a painting.
Thus, we see pastel or conte drawings in ochre and white only, and pastel paintings with a full spectrum of colors, nuances of hue as well as nuances of value.
Or, pen and ink drawings, in just black and white, or even with washes, still drawings - but pen ink works using a variety of uses labeled as paintings.
The use of a brush is usually synonymous with painting, but the use of non-brush instruments to apply paint, and the recent large range of hues available for crayon and pencil applications, have blurred that distinction as well.
And to further complicate matters, people tend to think of any work that focuses on line - including cross-hatching and stipple, as a drawing, regardless of the medium or tool used, including work created with a brush, and tend to characterize anything created in areas of tone or hue, as painting. So you can have a drawing in paint, traditionally as the underpinning for a oil painting, or a painting made of areas of tone and value created in charcoal.
But there doesn't seem to be any universally accepted definition, and actual usage by both artists and viewers is pretty flexible. Critics seem to change their minds about the matter every generation or so.
