Use the Labels feature to add colored labels to your pictures, to help sort them by a system of your own.
To add labels to pictures, use the Descriptions Panel, or use the Information | Image Information [Shift+Enter] window’s Descriptions tab. Alternatively, use the Browser’s Information | Label submenu or the [Shift+1] through [Shift+9] hotkeys. To remove any existing rating from the picture, click None or use the keyboard shortcut [Shift+0].
Keyboard shortcuts for labels can be customized. Open Settings [Ctrl+M] and click on General. There is a button Keyboard Shortcuts. It will open a new window where you can find the option Manager in the top left corner. Clicking on it will allow you to change the option to Labels and define your own shortcuts.
The label (if any) for a picture is indicated in its Browser thumbnail, by an icon at the bottom right. Right-clicking that icon calls up a menu where you can change the rating or remove it (the “-” item).
To set which colors are used for labels, use Settings | Preferences | Labels. Here you can define up to 9 custom labels or choose colors used in other programs. Label information is stored within a picture’s XMP-type picture information.