Drawing Basics: Value relationships

It is easy to think of value as a stable element in a composition. For example, dark hair is dark hair.  An artist would always use the same value to paint the hair, right? After taking a look at a value scale that is set up in distinct steps it might seem so. But what effects does the environment have on the hair? Or more specifically, how do the values in the areas around the hair affect the look of the value level of the hair?

Today, we will look at one aspect of value relationships that can change the look of the image with a simple exercise.

Let's begin.

Two Dots: Value Comparision

Value of the Dots

Like color, the appearance of a certain value is dependent on the values that are near or around it. This means that the value level of an area of an image has a unique relationship to the values surrounding it. The result or how we interpret what we see is dependent on how the different values interact with each other. 

Take a look at the image to the right. Which dot is darker?

Here is the same image with a square added. The square is made up of the middle value of our value scale. Does this change anything?

Back to our original question, which dot is darker?

By removing the gradient background, it is easier to see the value level of the two dots and the square. As many of you probably figured out in the original image above, the values are all the same. 

It is the value level of the background area surrounding each shape that creates an illusion of difference between the shapes. The dot against the light background appears dark. The dot on the darker background appears lighter.

This is because the local value near each dot impacts how we visually interpret how we see that value.

A fun exercise to test this concept is to paint something and change up the values of the background to see the relative nature the relationships can have. Below is an example of such an exercise. Try it out.

Take a small canvas, mine is 5 x 7 inches, and paint a portrait of someone using only black and white paint. Set the person against a very dark background. Here, I painted the background the darkest value I could.

Paint the portrait using the middle value and values close to it. The values in the face should appear light at this stage.

Once the painting is dry, repaint the background a very light value. In this example, I painted white right over the dark background.

Notice as you change the background how the values in the face seem to shift from being light values to dark ones.

Here is a side-by-side comparison of the before and after of the painting. The value levels used to paint the head and shoulders are the same in both images.  There is a dramatic shift in how we perceive those values when we change the background.
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For more on value and value scale:

Value Scale