Today’s Question: In Lightroom I created 1:1 previews for a series of images. I’m in the Develop module zoomed to 100%. When I move using arrow key to the next image in the series, the image on screen is first pixelated, then improves to just blurry, then finally improves to actual sharpness. Each change takes just about a second. Very annoying. If 1:1 previews already exist, why is the rendering happening in 3 stages rather than simply opening at actual/proper resolution?
Tim’s Quick Answer: Put simply, Lightroom generates updated previews “on the fly” in the Develop module. You get the full benefit of 1:1 previews in the Library module, for example, but in the Develop module Lightroom will render a preview in real time based on the original capture plus the adjustments you’ve applied. In other words, the final preview takes longer to generate than simply retrieving the preview from the cache as is done in the Library module.
More Detail: In other words, you can think of the 1:1 previews as being a feature to employ as needed in the Library module. In the Develop module Lightroom will be working a bit harder to generate updated previews based on your original capture plus adjustments. That, in turn, means that overall system performance can play a very big role in the Develop module.
In particular, a fast process, plenty of memory (RAM), and a good display adapter (video card) with plenty of video memory will make a big difference. In general I recommend 8GB to 16GB of system memory, a fast processor with multiple cores, and 2GB or more of video RAM.
In addition, it is a good idea to confirm that the “Use Graphics Processor” checkbox is turned on. You can find this checkbox on the Performance tab of the Preferences dialog in Lightroom. The only reason I would ever turn this option off is for troubleshooting odd behaviors within Lightroom. But if Lightroom is behaving normally, leaving this option turned on will improve performance, including within the Develop module in Lightroom.
If you have adequate hard drive space, I would also recommend increasing the size of the Camera Raw cache in Lightroom. The default is 1GB, but you can increase it to a much higher value (like 10GB or 20GB) to improve performance. You’ll find this option near the bottom of the File Handling tab of the Preferences dialog in Lightroom.
Note, by the way, that rendering 1:1 previews can greatly improve overall performance in Lightroom. They are not as beneficial for the Develop module compared to the Library module, but they can still boost performance. If you have more than enough hard drive space, it may be worthwhile to render 1:1 previews depending on your particular workflow.