While PDFs of public domain works are widely available, The Negative (first published 1981) remains under copyright. We encourage acquiring a legal digital copy through official retailers or your local library’s digital lending system to support the Adams legacy.
: Managing different light qualities.
Adams was a master of manipulating the "performance" of the print from the "score" of the negative. Dodging and Burning
: Represent middle gray and standard skin tones.
If you are looking for digital scans of his actual negatives or technical sheets, you can explore these authoritative archives: The Ansel Adams Gallery
: Understanding how we see vs. how film "sees."