Final answer:
Giotto used the chiaroscuro technique to give figures a three-dimensional appearance, which was revolutionary for the Renaissance period and marked a move towards more realistic and naturalistic depictions in art.
Step-by-step explanation:
The technique that allowed Giotto to give figures a three-dimensional quality is chiaroscuro. This artistic method was popularized during the Renaissance, and it involves the use of exaggerated light contrasts to create the illusion of volume. Thanks to chiaroscuro, artists like Giotto were able to depict highly expressive and lifelike figures, moving away from the flatter, more stylized imagery of the Byzantine tradition.
Giotto's style, with its use of foreshortening and chiaroscuro techniques, represented a significant shift towards naturalism in Italian painting. This move was part of a larger trend that saw the development of other important techniques in Florence during the early 15th century, such as the use of realistic proportions and sfumato. The chiaroscuro technique specifically allowed for a dramatic interplay of light and dark, hence contributing greatly to the visual realism that became a hallmark of Renaissance art.