Certified Animation Professional (CAP) Practice Test

Which color channel in the RGB model does not affect brightness when set to 0?

1. Red

2. Green

3. Blue

4. All channels

The correct answer is: All channels

In the RGB color model, colors are created by combining different intensities of the three primary colors: red, green, and blue. Each color channel can have values ranging from 0 to 255. When any channel is set to 0, it effectively means that color contribution is completely removed from the final output. When considering brightness in this context, brightness is influenced by the overall intensity of the colors that are present. If all channels—red, green, and blue—are set to 0, the resultant color will be black, which has no brightness. Therefore, if any one color channel is set to 0, while the others may still contribute to the overall brightness depending on their values, the option stating "All channels" indicates that when they are all set to 0, they do not contribute brightness, resulting in complete darkness. This understanding clarifies that indeed, when any of the channels is reduced to 0, it does not affect brightness in terms of contributing light to a color. Hence, all channels, when set to 0, result in the absence of brightness.