During the 1940s, Franz Kline's art underwent a significant transformation that would eventually position him as a key figure in the Abstract Expressionist movement. Initially, Kline's work was representational, capturing the animated subjects and industrial landscapes reflective of his Pennsylvania roots. This period of his career was characterized by simple gestures or strokes that translated his observations of the world into art, indicating an early exploration of the themes and techniques that would dominate his later work​ (Peggy Guggenheim Venetian Art)​. Kline's transition toward Abstract Expressionism began in earnest toward the late 1940s, catalyzed by key interactions and influences within the New York art scene. His friendships with artists like Willem de Kooning, Jackson Pollock, and others exposed him to the burgeoning movement and its emphasis on abstraction and expressive, gestural painting​ (Wikipedia)​​ (The Art Story)​. A pivotal moment in Kline's career occurred in 1948 when Willem de Kooning suggested he use a projector to enlarge a sketch onto the wall of his studio. The result was a dramatic, abstracted image that captivated Kline and propelled him towards the large-scale, black-on-white abstract works that would come to define his mature style. This technique, focusing on the interplay of negative and positive space, marked Kline's departure from representational art and his full embrace of abstraction​ (Wikipedia)​. By the end of the 1940s and into the early 1950s, Kline had fully developed his iconic style characterized by bold, black strokes against white backgrounds. His work from this period, while abstract, continued to suggest the vibrant energy of urban life, blending the influences of his industrial upbringing with the dynamic atmosphere of New York City. This style was both a personal expression and a reflection of the broader movement towards Abstract Expressionism, distinguishing Kline among his contemporaries​ (The Art Story)​. Kline's work during the 1940s laid the groundwork for his recognition as a leading figure in Abstract Expressionism. His explorations during this decade reveal an artist in transition, moving from the representation of the external world to an abstract, internal expression of emotion and energy that would define his legacy in the art world.