Neutral or Gray Balance

Explain the purposes of gray balance and indicate why the black ink is not used for gray balance.

Black ink cannot be used in reproducing neutral or gray areas because they need to be neutral to look like the original which is a created by combining equal amounts of red, green and blue. When using process color for reproduction on white paper it is very apparent when there is any imbalance. The printer uses a balanced combination to cyan, magenta, and yellow to create an accurate neutral in the reproduction. Using black in this reproduction would not create an accurate neutral. Keeping in mind that the impurities in ink, and the fact that they do not reflect equal amounts, the amount of each ink is shifted to create neutral results.

With a combination of equal amounts of red, green and blue light a neutral or gray can also be produced. The light will be diffused through or reflected off the object in equal amounts of red, green and blue and it will look neutral.

Resources:
AIO Lecture