archivesofamericanart:

The papers of Southern California painter and instructor Hassel Smith have been fully digitized:
https://www.aaa.si.edu/collections/hassel-smith-papers-5714

Hassel Smith (1915-2007) was a Bay area abstract expressionist painter, painting instructor at the California School of Fine Arts, and a lecturer at the University of California. His papers include correspondence, personal business files, teaching files, writings, sketches, printed materials, photographs, and sound recordings.