A tour of the three iPad/Photoshop connected apps mode possible by the new Adobe Photoshop Touch SDK. Adobe iPad apps drive Photoshop (photos)

Adobe's traditional user base of creatives are some of the most computationally resource-intensive folk I can think of (along with hard-core gamers and scientists). So how does a company like Adobe jump on the tablet money train without having to develop a host of new applications Let others do it for them. And voila: the Photoshop Touch software developer's kit, which will make it possible to create an ecosystem of tablet-based products capable of driving Photoshop. Along with the SDK, Adobe's delivering three iPad apps designed to use it: Color Lava, Eazel, and Nav.

It's a great idea: Since a tablet is too underpowered to do "real" work, why not make it the interface to a computer that does the heavy lifting Of course, it's not a new concept--just a thin client reborn for the 21st century, or alternatively, turning your PC into a cloud. It will enable app development for Android, BlackBerry, and iOS platforms, in addition to Mac OS and Windows systems.

Plus, since the apps only work with Photoshop CS5 (with a free update patch to 12.04), it may serve as an inspiration for all those laggardly CS4 upgraders to cough up the bucks. Or subscribe. By default, the SDK communicates via iTunes and Bonjour, if you don't have either, you can configure it to operate via a peer-to-peer network.

In my mind, the three apps aren't terribly useful, except as illustrations of a few types of ways the SDK interacts with Photoshop. So I was really surprised when I saw that Adobe was charging for them. (For a step-by-step discussion of how the apps operate, click through the slide show.) My favorite, Adobe Color Lava ($2.99), allows you to mix colors like paints and generate five-color palettes' the individual colors can be sent to the current color chip in Photoshop, or entire palettes can be uploaded to the Swatch palette. It's fun and clever, but the lack of color matching on the iPad or iPad colorspace simulator in Photoshop makes it frustrating. You've agonized over the perfect mix of colors only to find it they look different on the PC.

Adobe's charging $4.99 for Eazel, a painting app whose main claim to fame seems to be that the colors run--not in any physically accurate way, or even in an artistically attractive way. They just run on curves and intersections. The paint "dries" over time, changing how the colors run together, but you can't tell how dry it is. Besides, one of the advantages of digital over the real world is that you usually don't have to wait for physical effects to occur. And as an example of the SDK it's weak. All you can do is transmit the image to Photoshop, which uprezzes it but doesn't improve the rendering of the paint. If you're really into painting, spend the ten bucks on Brushes.

Finally, I have mixed thoughts about the $1.99 Adobe Nav. This app turns the iPad into a tool palette, where you can create a custom subset of Photoshop's tool palette. In action, selecting a tool selects it in Photoshop. There's also a view that lets you scroll through and select all the photos currently open in Photoshop. I found it awkward to use as a dedicated control panel. Yes, it means you can use Photoshop in full-screen mode without losing access to the tool icons, as if it were a dumb second monitor. But you can't save parameter information along with the tools (such as 300px by 400px rectangular selection), so you end up going two-handed to the keyboard anyway. if you're really proficient with Photoshop, shortcut keys are a faster and more fluid way to work.

If you're not as well-versed in Photoshop, you're better off using the on-screen tools. Since it caches thumbnails of all the photos you've got open, Nav serves as a relatively easy way to get images onto an iPad' it can handle up to 200 at once. But it doesn't stash them in Photos, and if you reconnect to Photoshop and they're not open, it syncs them away. When you double tap on an image it displays really basic metadata--size, color space and bit depth. All it did was make me wish the SDK could drive Bridge or Lightroom as well as Photoshop.

In some ways, the apps illustrate potential limitations of the SDK because of constraints of the platforms it embraces. For instance, they can't pass information to each other, such as passing a palette from Lava into Eazel. That's a platform issue. (Caveat: I haven't seen the SDK documentation, my comments are based on observation.) Even more disappointing, none of these apps are nearly as interesting as the standalone apps that Adobe's been working on and uncommittedly previewing or that third-party developers have been creating for Lightroom, or other standalone painting apps.

That said, I do see the potential possibilities of the SDK, for operations such as tethered shooting, remotely activating scripts to run batch processes, or say, an app that allows you to perform rough edits on a proxy version with a client that can output an edit list for later full-on (or script-based) retouching. Once the whole color management thing is figured out, of course. Those are apps I'd say are worth paying for.

The apps should be available now via the App Store' the Photoshop Touch SDK is free to any licensed user of CS5, downloadable from www.adobe.com/devnet/photoshop.