How did Claude Lorrain use drawings to study nature?

Claude Lorrain primarily used drawings as his standard method for studying nature. While he occasionally painted directly from nature during his early career, his most consistent practice involved taking sketching expeditions into the Roman Campagna.1

During these excursions, he produced spontaneous studies of informal motifs—such as trees, ruins, waterfalls, fields in sunlight, and sections of riverbanks—using chalk, pen, and wash. Many of these nature studies were originally executed in bound books that were later broken up. These drawings served as a vital foundation for his artistic process, allowing him to capture the natural world before incorporating those observations into his carefully prepared studio compositions.1