Last week I tried to demystify the import process, so it seems fitting to do the same with the export process. Part of what confuses people are the words Import and Export as it implies that your photos are going in and then out of Lightroom, but in reality it is data about your photos that goes into and then out of Lightroom. Let’s take a closer look at what really happens during export.
In a nutshell, exporting is the way to apply the changes you have made in Lightroom, everything from Develop adjustments to keywords, to new copies of your imported photos. The key word to keep in mind is copies. Lightroom is not applying these changes to your source photos.
Read Understanding the Lightroom Export Process over at peachpit.com.