Certified Professional Photographer (CPP) Practice Exam

Mixed at full strength, what do red, green, and blue light produce?

1. Black light

2. White light

3. Gray light

4. Colorful light

The correct answer is: White light

When red, green, and blue light are mixed at full strength, they combine to create white light. This phenomenon is a fundamental principle of additive color mixing, where different colors of light are added together to produce new colors. In this case, red light, when combined with green light, produces yellow. Adding blue light to this combination expands the spectrum, resulting in white light. This is how digital screens and various lighting technologies operate, using the three primary colors of light to create a full range of colors, with white light being the result of their full intensity together. The other options do not accurately represent the result of mixing red, green, and blue light at full strength. Black light would imply the absence of light, gray light represents a mixture that lacks full intensity, and colorful light is too vague and does not specify the resultant mix under the conditions described. Therefore, the mixing of these three colors at their full intensity distinctly results in the creation of white light.