Aperture 2.1 now supports third-party editing tools. (Credit: Apple)

Apple has added image-editing plug-ins for its Aperture photo editing software as part of a new release of the product.

Aperture 2.1 is a free download for those already running Aperture 2.0, which was released in February. The addition of support for third-party plug-ins gives Aperture users a way to use specialised editing tools not supported by Apple inside the application.

The new release is basically a software development kit for Aperture developers, and has been expected since the release of Aperture 2.0. It comes with one Apple-developed plug-in called Dodge & Burn, but other developers such as Nik Software, PictureCode, and Digital Film Tools are expected to bring their plug-ins to Aperture over the next several months, according to Apple.

Support for plug-ins is something that Adobe's Lightroom -- Aperture's nemesis -- has had since last year, but development of image-edting plug-ins for Lightroom has taken some time. Photoshop, Adobe's premiere photo-editing software, supports a wide variety of plug-ins that let photographers customise their photos, but supporting plug-ins in Lightroom and Aperture is trickier due to a requirement that all edits be reversible.

Apple is getting around that requirement by creating a new image file every time an Aperture user starts using one of the third-party plug-ins, said Joe Schorr, senior product manager for photo applications at Apple. "One of our cardinal rules is never overwrite what the customer brought into the application," he said.

For example, if you're editing a photo using Aperture's stock tools, and decide you want to make use of one of the third-party tools, opening that plug-in will result in the creation of a new image file. That way you have the original copy on hand if the edits that looked great in your head don't translate to reality.

The software can also handle batch editing, where a particular edit is applied to two or more photos, Schorr said. There are a few other updates in the 2.1 version of the software, such as the ability to customize the adjustment panel with your favourite tools.

Aperture 2 was released in February. Development work on the plug-ins is already well underway at Apple's partners, Schorr said.