NAPS2 SDK is a free and open source scanning library for C#/.NET.

Scan with devices from Canon, Brother, HP, Epson, Fujitsu, and more. Then save to PDF, TIFF, JPEG, or PNG.

Features:

WIA, TWAIN, SANE, and ESCL drivers
PDF import/export and OCR
Share scanners on the local network
Modern .NET 6+ API
Windows, Mac, and Linux support