Section 3 | Page 9

In theory, a perfect ink process would absorb 100% of one primary color of light and allow reflection of 100% of the other two. If this were true, an overprint of all three process color inks would absorb all portions of the white light (red, green, blue), reflect no light back to the viewer and produce the appearance of black. In reality, printing inks contain impurities and no process ink is perfect. For example, even the best cyan ink does not absorb all the red light and does not reflect all the green and blue light. Therefore, when the three process inks are combined equally, a brown color is produced, not black. Black is used as a fourth ink to add depth to the shadow areas and enhance detail in the image overall.