For photo scans, Premium resolution is at 600dpi (dots per inch) and Expert resolution is at 1200dpi. For negatives and slides, Premium resolution is at 3000dpi and Expert resolution is at 4000dpi.   If you are looking to do edits or any other work on the files that we provide, we recommend that you choose Expert resolution.  Don't hesitate to contact us if you want to talk about these options further.