Today’s Question: Am I correct in understanding from your answer [on Friday] that in Lightroom Classic it is possible to see previews of photos even if they’re on a hard drive that isn’t connected to the computer?
Tim’s Quick Answer: Yes, in Lightroom Classic you can view previews of images in the catalog even when the source files are unavailable, and you can even apply metadata updates without those source files. I consider this to be one of the significant benefits of using Lightroom Classic compared to “browser” software such as Adobe Bridge.
More Detail: Lightroom Classic uses a catalog to manage the information about your photos, and that includes generating previews of images that serve as a cache stored with the catalog. Those previews can be viewed by simply opening the catalog, with no need to have the source images available as long as previews had already been generated.
For example, if you have your catalog on an internal hard drive and your photos on an external hard drive, you can view the images previews from the catalog even if the external hard drive containing the actual image files is disconnected from the computer. You can even update metadata, such as assigning star ratings and keywords, based on the previews in the catalog without having the source files available.
With standard previews the only limitation is that you’re not able to apply adjustments to images via the Develop module, and you’re not able to export copies of photos. However, if you build smart previews for photos in your catalog, you can work in the Develop module or export copies based on those smart previews.
