(IANAL) I don't think there are any all-encompassing rule. The e-Sign act affects the legality of electronic signatures, and probably has an effect, but don't think there's a single law.
Financial institutions are able to scan everything, when I was at a CU, we used Fujitsu scanners (fi-6140 - amazing workhorse) and destroyed everything except original mortgage notes.
The only area I know of that's problematic is scanning and archiving documents under apostille. Apostilles are arcane, and their validity is related to the seal remaining intact. They're pretty: for example, I've seen docs from China with the apostille attached to documents using a ribbon and a wax seal. Try scanning that.
Financial institutions are able to scan everything, when I was at a CU, we used Fujitsu scanners (fi-6140 - amazing workhorse) and destroyed everything except original mortgage notes.
The only area I know of that's problematic is scanning and archiving documents under apostille. Apostilles are arcane, and their validity is related to the seal remaining intact. They're pretty: for example, I've seen docs from China with the apostille attached to documents using a ribbon and a wax seal. Try scanning that.