We prefer to scan photos at 600dpi. Although this results in a little more time spent scanning, you end up with digital images suitable for large reprints (in most cases). If you are simply scanning photos to be archived digitally with no desire for reprints, 300dpi is perfectly suitable. However, using 600dpi (assuming you are sending us photos that are at least 4×6 in size), reprints can be made up to 11×14.