TIF

(.TIF file extension, pronounced Tiff) TIFF is the format of choice for archiving important images. TIFF is the leading commercial and professional image standard. TIFF is the most universal and most widely supported format across all platforms, Mac, Windows, Unix. Data up to 48 bits is supported.

It is not necessary to say much about TIF. It works, it's important, it's great, it's practical, it's the standard universal format for high quality images, it simply does the best job the best way. Give TIF very major consideration, both for photos and documents, especially for archiving anything where quality is important.