They may make many sketches before attempting a final portrait. Explain that students will each make several sketches and a guide or reference sketch about face proportion that they can keep and refer to when they begin their final drawing. Many artists use mathematics to help them understand proportion. They will all use rulers to measure and calculate correct proportion of their portraits. Artists carefully observe the real world .
Many artists study live models.
Choose a model from the class to come forward and sit. For this lesson, be sure students have a level front view of the model's face. Use a ruler to determine correct proportion. If you can erase, make purposeful mistakes to encourage them to look critically at the results. Use your ruler to divide your drawn head in half.