

This will probably be installed via your operating system, but you may need to contact your scanner manufacturer, especially for older scanners. Note:To use any scanner technology, you need to install a scanner driver. TWAIN should work for basic scanning needs, but if you experience issues with TWAIN, try one of the other scanning technologies described below. If you use a third-party scanning application, save your scanned images as TIFF files, then open them into Photoshop. These third-party utilities are dedicated scanning solutions, and they are more appropriate for critical or high-volume scanning. However, it is not always updated for new operating systems, and therefore may work less reliably than other scanning solutions, such as third-party utilities such as VueScan, the scanner software that comes with your scanner, or other scanning technologies.

TWAIN has been the main technology used for scanning in Photoshop for many versions.
