The color  appearance of an object depends upon the colors (wavelengths) of light that are reflected by the object to the observer's eyes. The object can interact with the incident light to absorb one or more colors of light. This is called color subtraction. The colors that are not absorbed or subtracted from the incident light are reflected to the observer's eyes.
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The Fundamentals
This Concept Builder will demand that you understand both color addition and color subtraction. The graphic at the right is a great starting point. It shows the three primary colors of light - red, green, and blue. It also shows the three secondary colors of light - cyan, magenta, and yellow. It is important that you understand that a secondary color of light can be thought of as being equivalent to a mixture of two primary light colors. In other words ...

• Magenta light = Red light + Blue light
• Yellow light = Red light + Green light
• Cyan light = Blue light + Green light

This is called color addition. 
 

The Incident-Absorbed-Reflected Model
A useful model for analyzing color questions is the incident-absorbed-reflected model. The model suggests that a successful analysis includes three steps ... with each step involving the answering of a question. Those steps or questions are ...

1. What primary color(s) of light are incident upon the paper?
2. Of the primary light colors that are incident, which color(s) is/are absorbed by the paper?
3. Of the primary light colors that are incident, which color(s) is/are reflected by the paper?

The absorbed light color(s) is/are subtracted from the incident light colors. This is called color subtraction. Once the subtraction process is complete, the result is the reflected light color. It is the reflected light color that reaches the observer's eye and determines the color appearance of the shirt.


Applying the Principles
In this question, you have to create the so-called color subtraction equation. You do so by tapping on buttons. Decide which primary colors of light are incident. That's easy ... it's in the words beside the diagram and in the diagram itself. Then we recommend determining which primary color of light is reflected. That's what the eye sees and the brain interprets. Do the reflected light color second. Finally, Do the Math! The incident light colors are either absorbed or reflected ... there's no other choices. So whatever colors were not reflected will be absorbed.  Do the absorbed light colors last.