A full backup contains all data at the moment of backup creation. It forms a base for further incremental or differential backup or is used as a standalone archive. A full backup has the shortest restore time as compared to incremental or differential ones.
An incremental backup file only contains data changed since the last full or incremental backup creation. Therefore, it is smaller and takes less time to create. But as it doesn’t contain all data, all the previous incremental backups and the initial full backup are required for restoration.
Unlike incremental backup, when every backup procedure creates the next file in a “chain,” a differential backup creates an independent file, containing all changes against the initial full archive. Generally, a differential backup will be restored faster than an incremental one, as it does not have to process through a long chain of previous backups.