Would you be embarrassed if your family and friends saw a videotape of your previous year 24/7?
From the time artists begin studying their craft, they concern themselves with the "values" of colors. For example, pure white may have a value of ten and pure black a value of one, with many shades (and values) of gray in between. If artists continue to dilute or add a different pigment to a particular color, they will no longer be able to identify the original color. Whether they are working in pastels, oils, or watercolors, a great challenge for artists is to keep their colors true and pure. No artist wants to end up with "mud," a noncolor. When something contaminates the purity of the color, the artist has to start over.
Portrait artists also must stay true to their subject. In the process of sketching the basic lines and adding and blending color and shading, it may become tempting to leave out a slight blemish, straighten a nose, or flatten the ears to make the final portrait "better." ...1