Smart Previews are a low resolution, fully editable preview version of your original RAW file.
Actually, they are DNG files, rendered in Lightroom with a size of 2540px on the long edge that are grouped into a .lrdata file next to your Lightroom catalog.
There are several advantages to using Smart Previews:
THEY INCREASE THE PERFORMANCE OF LIGHTROOM
As soon as you detach your RAW files Lightroom will switch to working with the smaller, lighter Smart Previews. Less data to process means it can be processed faster, hence increasing the performance of Lightroom.
Exporting JPEGs from Smart Previews is also a whole lot faster than generating them from RAW files. I’d guess around 5-10x faster.
YOU CAN SPLIT UP THE CATALOG FROM THE RAW FILES
While this is also possible without Smart Previews, with Smart Previews you keep the ability to access and edit the image of detached drives containing RAW files.
THEY SAVE SPACE
Yes, technically creating additional files on top of the already existing RAW files takes up more hard drive space. However, since Smart Previews allow you to detach your RAW files from your catalog without having an effect on the catalogs functionality you can build a Lightroom catalog that sits completely independently from the RAW files and can be fully functional.
For example, in my Lightroom catalog I have over 100,000 photos (that’s 1.2TB of RAW files), this equals 73GB of Smart Previews. Combined with my catalog file + regular preview file my entire Lightroom catalog is smaller than 100GB. I can fit that on my laptop!
THEY CAN ACT AS AN INSTANT BACKUP FOR YOUR IMAGES
Smart Previews are slightly compressed, low resolution DNG files from your RAW files. At around 2500px on the long end they are around 5 Megapixels. While they aren’t intended to be a backup in any form, you could technically extract the DNG files from the .lrdata file that contains the Smart Previews and re-generate your entire Lightroom catalog. It’s not ideal, since you’ve lost a whole lot of resolution, but it’s a nice to know that you’ll be able to still access a version of the original images.
Because you’re likely to split up the catalog from the RAW files when using Smart Previews you’ve add an extra layer of safety in case the drive with the RAW files fails.
50% OFF MY LIGHTROOM PRESET PACKS
You have 2 options:
1 – BUILD SMART PREVIEWS FROM OLD FILES
Select the images you want to build Smart Previews for, then click on:
Library > Previews > Build Smart Previews
2 – BUILD SMART PREVIEWS ON IMPORT (NEW PHOTOS)
In the Import Panel, make sure that on the top right hand side the box that say: Build Smart Previews is selected. Now Lightroom will automatically build the Smart Previews for you each time you import new photos.
There are several ways of checking if your RAW files have a Smart Preview attached.
1 – select the folder you want to check for Smart Previews, then, in the Library Module, press CMD (Ctrl) + F to open to filter panel at the top. Now, select Smart Preview Status on one of the available columns and make sure to turn off any other filters.
Click on ‘Has No Smart Preview‘, select all (CMD/Ctrl + A) and go to Library > Previews > Build Smart Previews. Done.
2 – Select the images you want to check (in Grid View in the Library Module) and see the status on the top right corner, under the histogram.
In the Develop Module you can see if you’re editing the RAW or the Smart Preview by checking the same area, top right, below the histogram. It will either say:
- Original: Original RAW file
- Original + Smart Preview: Original file attached & Smart Preview available
- Smart Preview: Original file not available & you’re editing the Smart Preview
Thanks for this post!
Quick question: will LR always right away work on the originals if the volume is attached? I am considering putting the RAWs on my NAS and having the smart previews on my SSD. Just, I would like to have the NAS always attached, however in that case, I figure, my workflow would be even much slower as LR would always first load the original over the network. It would be fantastic if LR would start instantly working on the smart prev and in the background start loading the original.
What’s your experience?
Hi,
I haven’t used it in connection with a NAS. But Lightroom will always use the Smart Preview first and then load the original file once you zoom in or want to export the file.
So, without being 100% sure it this, it think the NAS solution could work for you.
Hi Chris
, thank you for your very helpful videos and blog on workflow
I would like to know if I am correct in thinking that the workflow is to place your culled RAW images into a folder structure, go into Lightroom and create Smart Previews. I have three questions
1. I am assuming that it is possible to move the file structure from 1 Hard Dr to another, but one should not adjust the file structure as the Smart Previews would not be able to find their home files. Alternatively, the Smart Previews are really smart and I need not worry about this.
2. Once I have created the Smart Previews I can use them to edit images in Lightroom and dropping across into Photoshop as necessary when the SSD with the Smart Previews on is next attached to the computer with the RAW images, all the edits will be transferred, as I don’t want to destroy the original raw image does this go back to a copy of the raw image?
3. Additionally, if I am using other programs from within like the Nik Collection 3. These edits also survive and be transferred to the edited full-size image when the Smart Previews SSD docs with the hard drive with the RAW images on?
Please could you clarify these points, many thanks
Hi Richard,
Happy to hear that it was useful to you.
As to your questions:
1. As long as you change, move or copy things INSIDE Lightroom, the Smart Previews will stay connected to the RAW files. No need to re-connect anything.
2. You can’t edit Smart Previews in Photoshop, as this is a pixel-based editing process and you’re manipulating pixels in Photoshop. So you need the original pixels to work with. The Smart Previews are, essentially, a compressed, smaller (2500px long) DNG version of your original RAW files. When editing RAW files in Photoshop and saving them afterwards, Photoshop creates a PSD file and saves it next to the original RAW file. You shouldn’t lose any data this way.
3. Can’t say for sure as I don’t use these plugins. But it would be an easy test: Import a RAW file into LR, Generate the Smart Preview, disconnect the RAW file (rename it or move it outside of Lightroom), try to edit the same file (now LR is using the Smart Preview as it will tell you this under the Histogram), try to open this file with a third party plugin and edit it, then reconnect the RAW file again so Lightroom detects it and see if the edit is transferred or if Lightroom.
Hope this helped.
Chris