Producer unit system

Near the end of the one-reel era, the director-unit system gave way to the producer-unit system. While studios maintained director-led units, many of the managerial tasks, particularly in the pre-production phase, that had traditionally fallen to directors were assumed by central managers. Thomas Ince of Triangle stopped directing in the early 1910s and soon became one of the industry's first – and most powerful – central producers, running a 43-acre studio facility with over 1,000 employees. This system was closely linked to the rise of feature filmmaking, which required significantly greater investments per film and therefore much more detailed planning and managerial oversight than in the one-reel era.
This control over production was accomplished primarily through the continuity script – essentially a complete blueprint for and record of a film shoot. The continuity script featured many of the same elements as the earlier scenario script, but in significantly greater detail. It also contained shooting dates, highly detailed description of actions, footage estimations for each shot, complete budgetary data, and information on release prints and distribution. The evolution of the continuity script is concurrent with a set of profound changes in film style, as filmmakers began to explore in earnest scene dissection (i.e., the division of scenes into multiple shots). This emerging mode of representation required careful attention to the proper matching of positions and movements across shots – and the most effective way to do so was by planning every detail in advance. The continuity script led to a further division of labor within scenario departments, with "creative" personnel responsible for developing film stories and continuity experts responsible for converting them into detailed scripts.