Where does it fit in?
Lightroom is designed to take care of all your digital photography needs, from copying images from your camera’s memory card to sharing them with the outside world. It’s an all-in-one hub for the whole of your digital photography.
But that’s not to say it can do everything. There will be some image-editing jobs that need the extra tools in Photoshop or the specialised effects (and inspiration) of plug-ins like the Google Nik Collection, Perfect Photo Suite and others.
Lightroom does support external image-editors and plug-ins, so it may not be the only software you need, but it can act as the ‘hub’ for everything you do.
How does it work?
Lightroom Catalogs store information about your pictures, but not the pictures themselves. These stay where they are on your computer’s hard disk, though Lightroom can also move or copy them to a more convenient location when you import them into your Catalog.
The Catalog is a database which stores a thumbnail image of your pictures, a larger preview and ‘metadata’, which includes things like the shooting information embedded in pictures by the camera, any keywords you add later, copyright information about who owns the picture and more.
When you ‘edit’ a picture, Lightroom stores your changes as a series of instructions – it doesn’t directly change the original picture. Whenever you view the picture in Lightroom, what you see is the picture’s appearance with these instructions applied. You only get a ‘real’ version when you ‘export’ the picture as a new file. This is how non-destructive editing works.
Unlike Photoshop and most other image-editing tools, Lightroom treats all file formats the same. It can read and work with RAW files directly, so it doesn’t matter whether you shot RAW files or JPEGs. RAW files offer extra flexibility in highlight and shadow recovery and white balance adjustment, but there’s no extra conversion process to go through.