These are stages one and two of painting a head. In the first picture the pencil drawing is glazed with a thin coat of burnt sienna acrylic.
In the second picture, oil colors are blocked quickly one next to the other with a flat brush, in this case a number 4.
The picture on the left shows the blending of the colors. This is done with a soft, round, watercolor brush, number 6 for this one.
In the picture on the right we see the finished head. Details have been added as needed.
The whole process of painting the head has taken one hour. The size of the head is around 3.25" from the top of the head to the chin