Book Excerpt: 3D Game Textures: Create Professional Game Art Using Photoshop
June 22, 2006 Page 4 of 6
Color Systems – Additive and Subtractive
There are two types of color systems, additive and subtractive. Subtractive color is the physical mixing of paints, or pigments, to create a color. It is called “subtractive” due to the fact that light waves are absorbed (or subtracted from the spectrum) by the paint and only the reflected waves are seen. A red pigment, therefore, is only reflecting red light and absorbing all the others. In the subtractive system you get black by mixing all the colors together—theoretically. It is a challenge to mix pigments that result in a true black or a vibrant color. That is one of the reasons art supply stores have so many choices when it comes to paint. One of our advantages of working in the additive system is that we can get consistent and vibrant results with light. We won’t dwell on the subtractive system since we won’t be using it.
The additive system is when light is added together (like on a computer screen) to create a color, so naturally we deal with the additive system as computer artists as we are working with light. In Figure 1-18 you can see how the additive system works. I simply went into Max and created three spotlights that were pure red, green, and blue and created my own Additive Color Wheel, or a visual representation of how the colors interact. Black is the absence of light (the area outside of the spotlights), White is all light (the center area where all three lights overlap each other)—the combination of red, green, and blue is the additive system. If you look at the Color Picker in Photoshop (Figure 1-19) you will see a vertical rectangle of color graduating from red through the colors and back to red. This allows you to select a Hue and use the Color Picker Palette to change the value and intensity.
|Figure 1-18: The additive system works by adding lights. Black is the absence of light (the area outside of the spotlights), White is all light (the center area where all three lights overlap each other): the combination of red, green, and blue is the additive system.|
|Figure 1-19: The Color Picker in Photoshop has a vertical rectangle of color graduating from red through the colors and back to red. This allows you to select a hue and use the Color Picker Palette to change the value and intensity.|
The three primary colors in the additive color system are red, green, and blue (RGB). They are referred to as primary colors because you can mix them and make all the other colors, but you can’t create the primary colors by mixing any other color. Many projection televisions use a system where you can see the red, green, and blue lens that project the three colors (RGB) to create the image you see using the additive method.
The secondary colors are yellow, magenta, and cyan. When you mix equal amounts of two primary colors together, you get a secondary color. You can see that these colors are located between the primary colors on the color wheel and on the Photoshop Color Picker vertical strip.
Color is often used for emphasis. Look at Figure 1-20. All things being equal, the larger shapes dominate, but the small shapes demand your attention once color is added. Of course, there are many other forms of emphasis you can use in creating art, but color can be the most powerful—and overused. Ever come across a web page that has a busy background and every font, color, and emphasis devised by man splashed across it? There is almost no emphasis as all the elements cancel each other out. Often, less is more.
|Figure 1-20 All things being equal, the larger shapes dominate, but the small shapes demand your attention once color is added.|
In another example using a photograph, in Figure 1-21, you can see that in the first black and white photo, your eye would most likely be drawn to the dark opening of the doghouse and you would most likely assume that the subject of this picture is the doghouse. In the second version the colorful flower draws the primary interest, it still competes with the doghouse door for attention, but you would probably make the assumption that the focus of this picture was the flower.
|Figure 1-21: Your eye is most likely drawn to the opening of the doghouse in the black and white photo, but add color, and the flower draws the primary interest.|
In a game scene you can see the use of color drawing the attention of a player to an important item. Look at Figure 1-22. In the first version of the scene you are drawn to the fire and then look around at all the items in the shadows. In the second version the red crate draws your attention and clearly means something. Depending on the world logic of the game you are playing, that could simply mean that you can interact with the object, or it could mean the item is dangerous. That decision brings to our next topic, color expression.
|Figure 1-22: In a room full of normal objects, the players’ eyes will be drawn to the fire and then equally to the objects. In a room full of normal objects, a red crate draws attention, especially given the fact that there are other normal crates around it.|
Color Expression or Warm and Cool Colors
When you start painting textures and choosing colors, you will want to know how they react together in terms of contrast, harmony, and even message. There is a lot of information on this topic and once again, Johannes Itten enters the picture (the guy who did the color wheel). Johannes Itten has provided artists with a great deal of information on how color works and how they work together. Itten was among the first people to look at color, not just from a scientific point of view, but from an artistic and emotional point of view. He was very interested in how colors made people feel. From his research we get the vocabulary of warm and cool colors.
We all are familiar with this convention as it is mostly based on the natural world. When asked to draw a flame, we reach for the red or orange crayon, ice is blue, the sun yellow. Each warm and cool color has commonly associated feelings for them, both positive and negative. The brighter or more pure the color, the more positive the association. Darker and duller colors tend to have the negative connotations associated with them.
The warm colors are red and yellow, while the cool colors are blue and green. Children will color the sun yellow and ice blue and use the black crayon to scratch out things they don’t like. Traffic lights are hot when you should stop or be cautious (red and yellow) but cool when it is okay to go (green). Red and orange are hot and usually associated with fire, lava, coals. How many red and black shirts do you see at the mall? Red and black generally symbolizes demonic obsession. Red by itself can mean royalty and strength as well as demonic. Deep red can be erotic. Yellow is a hot color like the sun, a light giver. Yellow is rich like gold as a pure color. A deep yellow (amber) window in the dark of a cold night can mean fire and warmth. But washed out or pale yellow can mean envy or betrayal. Calling a person yellow is an insult, meaning he is a coward. Judas is portrayed as wearing yellow garments in many paintings. During the Inquisition, people who were considered guilty of heresy were made to wear yellow. Moving into green, we think of lush jungles teaming with life. As green washes out, we get a sense of dread and decay (zombie and orc skin). Vibrant green in a certain context can be toxic waste and radioactive slime. Blue in its saturated state is cold like ice, fresh like water and the sky. Darker blues are misery. Purple is mysterious and royal.
Keep in mind that color is context-sensitive. Water is generally blue; would you drink dark green water? But not just any blue will do. In the real world, if we come across water that is a saturated blue that we can’t see through, we get suspicious. Was this water dyed? Are there weird chemicals in there? If anything lives in that, then what could it be?! Blood is generally red, but what if an enemy bled green? What if the game you are playing is about an alien race taking over earth and one of your companions bleeds green from an injury during combat? In a fantasy game you might come across coins. Which coin do you take, the bright yellowish metal or gray-green metal? With no previous information on the color of coins in this world, most people would pick the brighter yellow. Look at Figure 1-23. What are some of the assumptions you might make about these three scenes?
|Figure 1-23: These three scenes are the same, except for the ax. What questions and/or assumptions run through your mind looking at each version?|
Looking at color in this way may make it seem a bit mechanical, but it still takes a talented artist to make the right color choices. You can memorize all the information in the world, but it usually comes down to having a good eye and being able to convey that vision in your work and to your coworkers.
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