As many of you know, Adobe released a beta version of Lightroom 4 yesterday. There are some major changes to the Develop Module—the Brightness slider has disappeared, while the Recovery and Fill Light tools have been replaced by Highlights and Shadows. Adobe says these Highlight and Shadow tools were improved, and a quick test bears this out—I was able to recover detail in an overexposed moon with Lightroom 4 and not with Lightroom 3. There’s also a new Whites slider, the Blacks slider is quite different, you can adjust individual color channels with the Point Curve—and they’ve changed the default settings.

I’m looking forward to experimenting with the new tools, figuring out the new defaults, and sharing with you what I learn. In the mean time you can watch Julianne Kost give an overview of the new features, or describe the specific changes to the Develop Module. To download the beta, click here.

Remember that this his a beta, so it’s bound to have bugs, and the final shipping version will be different, so adjustments you make now might not translate to the finished version. If you want to import a few images into the beta version to try it out, great, but I don’t recommend that you start using Lightroom 4 beta as your primary tool until the final version ships.

You can’t upgrade your current catalog to Lightroom 4, which is good—you don’t want to mess with your existing catalog. Adobe also recommends that you don’t save metadata to XMP, and I wholeheartedly agree. Don’t Save—don’t press Command-S on a Mac, or Control-S on Windows, and make sure the option to automatically write changes into XMP is turned off. It’s turned off by default in Lightroom 4, but to check go to your Catalog Settings (under the Lightroom menu on Macs, or under the Edit menu on Windows), click on the Metadata tab at the top, and make sure that “Automatically write changes into XMP ” is unchecked. And while you’re at it uncheck “Include Develop settings in metadata inside JPEG, TIFF, and PSD files” also.

Now in Lightroom 3 I do recommend—highly—that you check these boxes. To understand why, and what all XMP stuff means, we have to talk about some fundamental aspects of how Lightroom works, so if you want to delve into these details read on.

Lightroom is a non-destructive editor, which means that when you make changes to a photograph’s appearance, Lightroom does not modify the original Raw or JPEG file, but rather writes a set of instructions about how you want to the image to look. Those instructions don’t get applied until and unless you export the image out of Lightroom (like when you take it into Photoshop, or export a JPEG to put on a web site).

Those instructions are automatically written into the Lightroom database, and can also be written into the image file itself with JPEG, TIFF, PSD, and DNG files, or with other Raw files (NEF, CR2, etc.) into a sidecar file with a .xmp extension. So with Lightroom 4 you want avoid writing writing those instructions into the image file, or a sidecar file, because those instructions won’t be compatible with Lightroom 3, and may not be compatible with the final version of Lightroom 4. But with Lightroom 3 you want to write those instructions (the metadata) into the file or sidecar file so that if Lightroom catalog ever gets corrupted those instructions, your edits to all your images, won’t be lost, because the information will be stored with the image itself. Also, that information can be read by other programs, namely Adobe Camera Raw and other copies of Lightroom.

So with that said, have fun playing with Lightroom 4, and I’ll be back with more after I’ve given it a thorough test drive.