Collections allow you to create virtual groups of photos within your catalogs. You can also create sub-collections within a larger collection. Each collection tells you how many photos are in it, and you can pull them up just like other contact sheets.
When you
Create a collection by using the Create button or right-clicking in the collections section.
You can only create collections within catalogs that have Add/Modify enabled.
Once you have created a collection, you can add photos to it.
Select photos from a contact sheet. Right-click on the collection name and then select Add selected items here.
In order to add items into a collection, they must first be in that collection's catalog. If you try to add photos to a collection in a different catalog, Photo Mechanic Plus will offer to copy the photos into the catalog.
Sub-Collections
Just as you can add collections, you can create sub-collections within a larger collection. This acts as a virtual folder within your collection, but as with collections, it does not physically move your cataloged photos.
Create sub-collections by selecting the desired parent collection and then use the Create button or right-clicking on in the collections section.