John Singer Sargent (1856–1925) famously defined a portrait as ‘A likeness in which there is something wrong about the mouth.’ The mouth is probably one of the most expressive features of the face. I think lips can be one of the most challenging features because the mouth is a little more complex in structure and it’s easy to make lips too harsh or to suggest the wrong expression.
Lip colours and shapes
Use a brown or mix one from your red and black, keep it thin using a little turps and paint/draw the shape of your top lip. Alternatively, you can begin with the line produced from the meeting of top and bottom lip. Make sure you judge the distance to the base of the nose either visually or by comparative measurement. Top lips are usually a little darker than the bottom lip, which initially is just defined by the shadow running beneath the bottom lip. See how the top lip can be filled in with the brush whilst drawing. There are no drawn outside edges – the margin of the upper and lower lips is known as the vermilion border. In fact, when you study the outer edging of the lips, it’s lighter in value and contrasts with the lighter skin tone. The darkest line will be where the lips meet, which can be accentuated at some later point.