Associated with the New York School, Mitchell's paintings of the 1950s were composed of more refined and deliberately distributed brushstrokes and gestures compared to her work of the early 1960s.
Mitchell permanently changed her address from New York to Paris in 1959, where she lived with Jean-Paul Riopelle. Along with this change of environment came a significant change in her work. The paintings during this period seem to become more serious and dramatic, almost tragic in their aggresive style, perhaps characteristics initiated by the beginning of her mother's struggle with cancer in 1960.
It was in 1960 when Mitchell's technique exploded, taking her abstraction to the next level of her career's evolution. 12 Hawks at 3 O'clock is a burst of contrasting high and low value hues energetically contained in the plane of its towering canvas. The painting represents a pivotal period. It was the strength gained during this time that carries her innovation through the mid 1960s and most evident in the artist's "dark" paintings of 1964--a tragic time when she experienced the loss of several loved ones. The cloud-like elements in works such as Blue Tree (Worcester Art Museum) and Girolata Triptych (Estate of the Artist) both from 1964, become more focused as the surface becomes even darker. However, many paintings from this period contain remnants of brilliant colors, reflective of earlier works like 12 Hawks at 3 O'clock, whose richly saturated, deep tones prove to be the catalyst which carries her work through the "dark" period, transforming her palette into bright fields of color in the late 1960s. This underlying trait of dense color and light and reference to landscape then continued as a significant factor throughout Mitchell's career.