Recommended Scanning Resolution
Your scanning resolution will have a dramatic effect on file size. This article describes the recommended settings for getting the smallest file size possible without sacrificing image quality.
Most users choose to scan in black & white instead of color or grayscale. Black and white produces significantly smaller files and generally works better with OCR. Color scans produce very, very large files. Avoid color scanning unless there's a compelling need.
We recommend black and white at 300 dpi. At that resolution, you'll get a crisp, accurate reproduction of the original papers without getting a huge file. Some users lower the resolution to 200 dpi for even smaller files. The images will have a hint of a rough edge to them, but usually print clearly enough. You can try both settings and see which one you prefer.