Lightroom: Importing 100 Thousand Photos — Part 3

In this blog post we will discuss the crux of the matter when it come to importing a large amount of photos like I had to do, 93,259 photos.

The “standard” advice is to:

1. Render Previews 1:1 so that you don't have to wait when you are scrolling through the Develop module or browsing at 1:1
2. Apply During Import the Develop settings and the Metadata

The real question is: what's the purpose of the previews? To view an image, Lightroom must “create”, i.e. render, it. The more details you want to view, the more details Lightroom must create. All work in the Develop module is done at 1:1 and any Library at 1:2 and greater magnification¹.

The next question where are those previews stored? By default, these previews are stored in a folder name: catalog name + Previews.lrdata. Then the next question is how big? That's where it becomes fuzzy, the size depends on many factors:

1. The original raw file, 8Mb, 12Mb, 18Mb…
2. The color space sRGB vs aRGB of the photo
3. The number of image as 1:1, the number as standard, the number as minimal
4. …

If all the photos rendered as 1:1 and kept “forever” the size will between 120% and 200%. Yes, it's much bigger. In my case of 1.3 terabytes would mean between 1.5 to 2.5 terabytes of disk space needed. That's a lot of disk operations, that means a long, long time.

If you need to process a few hundred photos, it's OK to render the previews as 1:1, you still need to check the focus, and do the various processing. It takes almost 30 minutes (on my computer) to render 750 1:1 previews and it's not a linear curve. 7,500 1:1 is not 300 minutes/5 hours, but it comes close to 600 minutes/10 hours.