Why did Thomas Gainsborough paint landscapes from memory while living in Bath?

After moving to Bath in 1759, Thomas Gainsborough experienced a significant increase in demand for his work, as his studio was frequently filled with fashionable portrait sitters. Because these professional commitments left him with less time to paint landscapes from direct observation, he began working largely from memory.1

To facilitate this process, he often created small model landscapes in his studio and drew them by candlelight. Despite these constraints, he continued to produce idyllic landscape paintings, increasingly influenced by the work of Peter Paul Rubens during this period.1