This is the misconception that was targeted earlier in Lesson 2 as we discussed how visible light interacts with matter to produce color. This confuses many students of physics, especially those who still believe that the color of a shirt is in the shirt itself. Observe the representation of this by the diagram at the right and the equation below.įrom these two examples, we can conclude that a shirt that looks yellow when white light shines upon it will look green when cyan light shines upon it. Thus, the shirt will appear green in the presence of cyan light.

After the subtractive process, only green light remains. From this mixture, we must subtract blue light.

In this situation, we begin with only blue and green primary colors of light (recall that cyan light consists of blue and green light). What appearance will such a shirt have if illuminated with cyan light and how can we account for its appearance? To answer this question, the process of color subtraction will be applied once more. Now suppose that cyan light is shining on the same shirt - a shirt made of a material that is capable of absorbing blue light. Furthermore, the process is depicted in terms of an equation in the space below. The process is depicted visually by diagram at the right. In this process, the ultimate color appearance of an object is determined by beginning with a single color or mixture of colors and identifying which color or colors of light are subtracted from the original set. This discussion illustrates the process of color subtraction. Red and green light striking your eye always gives the appearance of yellow for this reason, the shirt will appear yellow. So while red, green and blue light shine upon the shirt, only red and green light will reflect from it. If the shirt absorbs blue light, then only red and green light will be reflected from the shirt. If white light is shining on a shirt, then red, green and blue light is shining on the shirt. To begin, consider white light to consist of the three primary colors of light - red, green and blue. What appearance will such a shirt have if illuminated with white light and how can we account for its appearance? To answer this question (and any other similar question), we will rely on our understanding of the three primary colors of light (red, green and blue) and the three secondary colors of light (magenta, yellow and cyan). Such a material will absorb blue light (if blue light shines upon it) and reflect the other frequencies of the visible spectrum. Consider a shirt made of a material that is capable of absorbing blue light.

We have already learned that materials contain atoms that are capable of selectively absorbing one or more frequencies of light. In this part of Lesson 2, we will learn how materials that have been permeated by specific pigments will selectively absorb specific frequencies of light in order to produce a desired appearance. Our understanding of color perception would not be complete without an understanding of the principles of color subtraction. Each of these applications involves the mixing or addition of colors of light to produce a desired appearance.

Principles of color addition have important applications to color television, color computer monitors and on-stage lighting at the theaters. These principles govern the perceived color resulting from the mixing of different colors of light. The previous lesson focused on the principles of color addition.

Does white out come in different colors