Final answer:
The dark printed words are easily read on a light background due to contrast, which refers to the difference in colors that makes the text stand out, enhancing readability.
Step-by-step explanation:
The dark printed words on a page of a book are easily read against a light background due to contrast. In principles of design, contrast refers to the arrangement of opposite elements to highlight their differences, enhancing the visual experience. In the context of reading, the sharp difference in color between the dark text and the light page amplifies the visibility of the text. This makes reading easier and less straining for the eyes. It's an essential aspect of design that draws attention to the important elements, like text in a book.
Contrast can also be influenced by size, shape, and texture, but it is the color contrast that creates a striking visual impact in this case. This is a classic example of how contrast works to make specific elements stand out and serves as a fundamental aspect of visual communication.