Today, I'd like to talk about how similar and opposing colors affect portraits by taking a look at two identical portraits whose only difference is the color of the subjects shirt. This image is a fairly straightforward traditional portrait, perfect for what we want to look at.
Whenever we want the object in our images to stand out from their backgrounds, we need to see a contrast between what we want our audience to focus on and what we don't. Often this contrast takes the form of opposing lighting, texture and pattern. Here, we are looking at contrasting colors. In the original image, the man in the photograph is wearing a purple plaid shirt. Unfortunately purple is very close to red on the color wheel. The similarities in the two colors makes it difficult for our eye to settle in one place. We intuitively want to look at the face but, the purple is trying to draw our eyes to the shirt as well. When our eyes don't know where to go, we lose much of the impact that we could get from the portrait.
In the second image, I have replaced the purple with green. Green is on the opposite side of the color wheel from the red hue that is prevalent in the face and provides a nice contrast. We refer to their relationship as being complementary. Red and green are complementary, purple and yellow are complementary as well as blue and orange.
However, I didn't stop at changing the Hue to green. I also desaturated the green and reduced it's brightness or luminosity to add further contrast with the subject's face. Now, our eyes are drawn very strongly to the face and don't even want to move to the shirt. Color is made up of three distinctive qualities (Hue, Saturation and Luminosity) and we have changed all three of them to maximize the difference in color.
Let's take a look at a second example. In this image of my cat, Betty, The over riding colors are the purple int he wall and the green in her eyes. Another color is the small bit of blue in her collar. Purple and green are complementary colors so, on the surface they look to be ok. The immediate problem is the blue. Blue clashes with both the purple and the green.
Eliminating the blue is pretty easy. I didn't want another patch of color, so I simple desaturated the blue until it turned to grey. Now the buckle simply disappears in to the muted colors of her fur.
With the blue eliminated, I decided that I wanted to place more emphasis on Betty's eyes. Remember the three components of color? Hues, Saturation, and Luminosity? I didn't want to change the hue, the green is her natural color and wasn't a problem in the presence of the purple. I thought the eyes had plenty of brightness so, I decided not to fuddle with the luminosity. That left saturation. By bumping up the saturation of the green, I was able to give more strength to her eyes. Now, without a doubt, you are instantly drawn to her eyes.