3F file format is a semi-automatic scan mode where the images are scanned at full-frame at full resolution at 16 bits per color. In this way the full tonal and colour range and crop of the original negative is extracted from the X-5. It is effectively a full spectrum “RAW” file of the negative. Once saved, much like a digital RAW file, the .fff can be processed many times without itself being altered with variations on Tonal output, colour balance, curves and levels being modified. Scan Unit will provide versions of the latest Flexcolor software to enable you to make you own adjustments.