Lightroom Catalog

by Wren McMains

I've only been using Lightroom for a year. In addition to a few test folders, each with only a few images. I imported two larger tree structures with original images:

In past discussions of organizing images I recommended copying your best images to a subject folder and working on them there. When your original images are RAW files, this isn't necessary. Editing JPGs with Lightroom is another story (see the next paragraph). The primary reason for the copy before editing was to make sure you didn't accidently modify the original image. A secondary reason was to have another backup of your best images, on a different drive if possible.

As far as I'm concerned, Lightroom is a disaster if your original images are JPGs. Every other editing program lets you edit an image, and if you're careful and save the edit under another name so the original isn't touched. If you start editing a JPG in Lightroom, Lightroom starts scribbling on the JPG file. In theory these are non-destructive changes. If you look at the JPG (without exporting) with another program you don't see the changes. However, if you copy the JPG to another machine and look at it in Lightroom the changes have been made and there is NO way to un-do them.

Moral: Never edit original JPG images in Lightroom. Keep the originals in a folder that is never imported into Lightroom.

Resulting Lightroom Catalog:

As a computer scientist I was a little surprised at the number of files and folders in the catalog. For the most part data base technology relies on very large indexed files.

Instead Lightroom stores image previews in individual files so you can expect the number of files in the catalog to be just slightly more than the number of images you've imported. Based on the way Lightroom names the folders, I believe the catalog will only grow to 65,000 folders, even if you have a million or more images in your catalog.

Just saying. I don't see anything wrong with the way Lightroom stores it's catalog. But I'll report back after I have more experience. One issue might be backing up your catalog to an external drive with a FAT 32 files system. This is the default file system on external drives because it is the only one that can be read by both Windows machines and Macs. Both the Microsoft NTFS and the Apple file system are better st storing lots of small files like these.

Image Previews

Lightroom gives you 5 choices for the size of the preview file: 1024, 1440, 1680, 2048, or 2880 pixels. The default is 1440 which is good for most of us. You can find this setting on the File Handling tab under Edit / Catalog Settings. Many of us use 1920 displays, I'll let you know if I think it's worth using larger previews. Lightroom also creates 1:1 previews as needed and then deletes them after a time (30 days by default).


My own advice to anyone using Lightroom:

Under Edit / Catalog Settings / Metadata check the box that says "Automatically write changes into XMP". IMPORTANT: this is catalog setting, so each time you create a new catalog, you must make the change again for that catalog.

This automatically stores keyword tags, stars, colors, etc. in your sidecar XMP files as well as in your Lightroom catalog so that information can be transferred to the rest of the world. Not only does it update XMP files, but it also causes JPG images to be updated when the metadata changes. Failure to check this box means your metadata will not be transferred to other programs (except when you export) and will not be backed up unless you backup your catalog.

Personally I use many programs to work on my images, so it is important to me that the metadata transfers along with the images. If you create new images using other programs in a folder you have previously imported to Lightroom, re-import that folder into Lightroom ... Lightroom will only import the new and modified images. If you've only changed the metadata there are options under the Metadata menu in Lightroom to read or write the data. There are also "sync" options, but if you check the automatic box you shouldn't need to worry about anything other than Import.

As long as you follow my recommendation (checking the box that says "Automatically write changes into XMP") you can always rebuild your catalog if something happens to it. Or you can use the same software that you use for incremental backups of your images to also backup your catalog. Just be sure you know where your catalog is. I have a spare SSD drive, I might consider adding it to the machine where I use Lightroom the most and put my catalog there.

I don't understand why this box isn't checked by default. As far as I'm concerned the benefits far outweigh the fraction of a second it takes to update a file if you change it's keywords, star rating, etc.

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