There are four master types in GN4:
| L | Automatic left: it is automatically associated to all even pages in an edition or template. It is shown in the list of master with the "L" label. Only one master in any edition may have the L type. However, at least one master must have this type. |
| R | Automatic right: it is automatically associated to all odd pages. It is shown in the list of master with the "R" label. Only one master in any edition may have the R type. However, at least one master must have this type. |
| D | Automatic double: it is automatically associated to all double pages. It is shown in the list of master with the "D" label. Only one master in any edition may have the D type. However, at least one master must have this type. |
| ( ) | Generic master: the master type for custom masters. It is shown in the list of master with the "-" label. It is not automatically used when adding new pages, but it may be manually assigned to pages. More masters may have this type. |
