Smart Previews are a handy feature of Lightroom that is often misunderstood. It can be a lifesaver for Laptop users who work while away from their original images, or can speed up image development on older PCs. This article will help you understand what Smart Previews are and how you can use them.
Dispelling the Myth
Before we dig too deeply into the world of Lightroom’s Smart Preview feature, we need to dispel a widespread myth:
Lightroom’s Smart Previews are not used at all while in the ‘Library’ module, they are ONLY used when developing photos.
The naming of the term Smart Previews suggests that they are in some way related to the Lightroom catalogue’s preview images used in the Library when browsing through your photos. This is in fact not the case. Smart Previews are only ever used in the ‘Develop’ module in Lightroom and are entirely separate from the embedded/standard/1:1 preview settings used in the Library.
What are Smart Previews in Lightroom?
Smart Previews were introduced in Lightroom 5.3 in response to the need for some photographers to browse through their Image Library and make changes while their external hard drive was disconnected.
A Smart Preview is a .dng (RAW) copy of your file, resized to be 2540px on the longest edge of the photo. The Smart Previews are saved alongside your Lightroom Catalog, so even if your original files aren’t available, you will be able to view and edit the Smart Preview. Any changes you make to the Smart Preview will then be synchronised with your original file next time it is available.
Creating Smart Previews
You can create Smart Previews for your photos in one of two ways.
1) During Import
When importing your photos, you can select the ‘Build Smart Previews’ option. This will create the Smart Previews as your photos are imported into the Photo Library
2) For Existing Images
If you want to create Smart Previews for existing images you need to select the images you want to create the previews for. Don’t worry if you aren’t sure if a preview already exists, Lightroom won’t re-create any already existing Smart Previews. Once selected you can then go to Library -> Previews -> Build Smart Previews. Lightroom will then start the process in the background. This can take a while if you are processing a lot of images so be patient.
Working with Smart Previews
Once you have created the Smart Previews, working with them is easy. Just disconnect the drive that contains your original images and Lightroom will automatically use your Smart Previews.
If you want to work with Smart Previews while your originals are still connected, you can do this as well. If you have an older PC, this may speed up developing your images as the files are much smaller than the originals. To do this, you will need to enable it in the settings:
- Open the Lightroom preferences via ‘File -> Preferences’ (or ‘Lightroom -> Preferences’ on a Mac)
- Go to the ‘Performance’ Tab
- Select the ‘Use Smart Previews instead of Originals for image editing.’
This will use Smart Previews even when your originals are connected; until you zoom in 1:1 which will load the original file if it is available so you can do Sharpening and Noise Reduction at the full-sized view.
What Can You Do With Smart Previews While Your Original File Is Unavailable?
As mentioned above, the most common use for Smart Previews is working on photos while your original files aren’t available (e.g. While out of the house/office working on a laptop). With Smart Previews created you can do most of the things you would typically be able to do if your original images were connected.
- Add, remove and edit Keywords and other metadata
- Edit the photo in the Develop module in exactly the same way as you usually would
- Export Photos in sizes up to 2540px on the long edge)
- Export files larger than 2540px on the long edge
- Print photos
What Are The Downsides of Using Smart Previews?
The only caveat is that as you are viewing a smaller sized photo than your original, you will have to be mindful of any sharpening and noise reduction that you apply as these are ideally done at a 1:1 pixel view which the Smart Preview doesn’t offer.
Also, Smart Previews do use up space on your hard drives. They are MUCH smaller than your original files, but you need to keep this in mind if your Lightroom catalogue is located on a small SSD Drive. For 35,000 images in my catalogue, the Smart Previews take up 33GB, which is just under 1MB per Smart Preview file.
When Should You Use Smart Previews?
There are a couple of different scenarios where you may want to use Smart Previews.
- You store your original photos on external hard drive or NAS but want to work while the drives aren’t available (such as on a laptop)
- You have an older PC that may work faster while working with Smart Previews than the original photos (don’t forget to change the setting as described above)
Deleting Smart Previews
If you have created Smart Previews and you find that you no longer need them, you can remove existing previews by going to the Library module, selecting the photos you want to remove them from and choosing Library -> Previews -> Discard Smart Previews from the menu. This will not affect your original images in any way.
Using Smart Previews are a great way to work on your photos while away from the hard drives that contain your original images. Weather on a Laptop with external hard drives removed or on a remote PC where your pictures may be back in the office. You will be able to perform most functions as if you had access to the originals.