The success of a portrait often relies on an artist's ability to quickly establish relationships, both on and off the canvas. It all starts when meeting your subject for the first time, whether it's a client, friend or model. During that time, the groundwork for building an open line of communication is set. This first impression is important because it's the one that most people remember and is often referred to as the basis for determining how the relationship will develop in the future. Once back in the studio, a new relationship begins to form on canvas, one brush stroke at a time.
Creating a sense of volume, depth and mood when painting a portrait involves an understanding of value relationships. Each color that you put on canvas has a "value" that's automatically assigned to it. This simply refers to how light or how dark the color is when measured on a scale from black to white. How these values work together as a whole throughout the painting is referred to as "value relationships". When correctly placed, good value relationships give the illusion of a third dimension in your subject.
In order to accurately build correct value relationships, you must first establish a value that remains relatively unchanged throughout the painting process. This value then serves as a reference point that can be used to judge how light or dark every other value in your painting will be. It's the foundation upon which you will build your entire value relationship. One way of laying this foundation is by first determining what the darkest value in your subject will be and then putting that value down on canvas at the very beginning. From there, you can then compare every other value in your painting to this first initial value.
Because value and color are so closely related, it's sometimes difficult to determine how light or dark a particular value should be when seen in color, especially if the difference in values is very subtle (often referred to as "close value relationships"). When working from photos, I find it much easier to notice these subtle value changes by converting a color photo to a black and white image. By eliminating the color, it's much easier to recognize the correct value relationships.
Remember, a good first impression will go a long way in helping you build a solid foundation with your subject as well as those who view your next portrait painting.