To understand what are the Master and the Incremental backups and the difference between them, please read the following information.
A master backup is a complete backup of everything from scratch. The backup process is slow and the generated image file is big, due to the fact that all of selected files are backed up.
However, the master backup acts as a base for all subsequent incremental backups, which means that a master backup must be created at first before generating an incremental backup.
This method will only back up the files that have changed since the last backup. The backup process is the fastest when and the least storage space is needed.