Adobe announced the availability of the Photoshop Lightroom 2 public beta last week, but a post on an Adobe blog generated almost as much attention. In addition to adding new features, the Lightroom beta is capable of taking full advantage of the 64-bit processors found in Mac Pro models. (64-bit support is also included with Lightroom 2 under Windows Vista.)
The rub is that Photoshop, Adobe's image editing powerhouse, won't gain 64-bit compatibility on the Mac for at least two revisions. In a blog post, Adobe's John Nack explained that the discrepancy between Photoshop and Lightroom is due to Photoshop's Carbon code base:
"At the WWDC show last June , however, Adobe & other developers learned that Apple had decided to stop their Carbon 64 efforts. This means that 64-bit Mac apps need to be written to use Cocoa (as Lightroom is) instead of Carbon. This means that we'll need to rewrite large parts of Photoshop and its plug-ins (potentially affecting over a million lines of code) to move it from Carbon to Cocoa."
As Nack elaborated, the lack of a 64-bit version of Photoshop isn't a crippling blow to the Mac. In fact, most of the blog post is devoted to heading off wild speculation about Adobe's or Apple's intentions (and pointing out that Final Cut Pro, iTunes, and the Mac OS X Finder are all built in Carbon). A 32-bit Photoshop CS4 will no doubt run just fine. It will just not have the capability to handle very large amounts of data (more than 4 GB) at once.
As for the actual software released last week, Lightroom 2 adds a number of new features such as multiple-monitor support, smart collections (the capability to group photos automatically according to metadata), and a clever method of suggesting related keywords as you tag your photos.
Lightroom 2 can also apply edits to select portions of an image instead of just to the entire image. (Aperture 2.1, released the previous week, added this capability through a new plug-in system; see "Aperture 2.1 Adds Plug-in Capability to Edit Photos," 2007-09-07.)
Existing Lightroom owners can participate in the beta until version 2.0 is released by entering their serial numbers. They can also invite friends to try the beta for the entirety of the program. For everyone else, a 30-day evaluation period is available. The software is a 24.7 MB download. The Lightroom 2.0 beta is installed independently of earlier Lightroom versions, so photographers can evaluate it without putting existing libraries and workflows at risk.