Since Adobe seems determined to lose me as a customer, I thought it high time I updated my roundup of credible Photoshop alternatives.

If you’ve been here before, you’ll know that I’m a Mac user (although I do find Microsoft’s Surface Pro to look pretty damn compelling as an artist’s tool) so I’m not really interested in Windows-only software such as Paintshop Pro. If you’re a Windows user, you should definitely consider Paintshop Pro, but I haven’t used it seriously in years and am not qualified to judge it.

Why Photoshop?

If you really need Photoshop, you probably know who you are.

Today, I use Acorn and Pixelmator frequently, and Adobe Photoshop CS5 more occasionally. I’m not doing much artwork professionally, and I don’t really need Photoshop’s capabilities most of the time. That said, Photoshop is incredibly powerful for workflow automation (e.g. both macro capabilities and its scriptability are unmatched).

If you want the best tool for working with layered, high dynamic range images, then you probably want Photoshop. Photoline can, supposedly, do some of this stuff, but it’s pretty dodgy. (That said, Photoshop is also not great in >32bpp modes.)

Similarly, Adobe’s applications are supremely well-integrated. After Effects can import Photoshop layered documents and animate them. Complex Illustrator files can be embedded in Photoshop as “smart objects” and be edited in-situ. In a production environment, these capabilities are simply unbeatable.

If you need this functionality, use Photoshop. It will pay for itself so fast that it’s not even worth discussing. I should note that very few people I’ve met take advantage of Adobe’s incredible scripting support.

Now we’ve gotten that out of the way, let’s look at the crucial differences between these three products. I’m not going to redo my giant comparison table right now, because very little has changed in terms of outright features. Instead, I’ll try to highlight the key differences between Photoshop’s leaner, cheaper rivals.

Photoline ★★★★★ (59 euros) is the most powerful of the three programs, in some cases giving Photoshop a run for its money (e.g. it has recently matched Photoshop’s smart delete and content-aware scaling functionality, and has extensively improved its high dynamic range capabilities, supporting 32-bit floats per channel). The one area where it seriously lags behind Photoshop is scriptability. It also lags Photoshop and its other rivals in terms of both UI refinement (Photoshop CS6′s UI has been dramatically refined over previous versions) and — more importantly — functional refinement.

As an aside, Photoline’s website and icon are so horribly ugly I think most artists would be repelled and never bother even trying it out.

• Powerful
• Cross-platform
• >32bpp support
• Like Photoshop has destructive filters, non-destructive layer styles and filter layers
• No scripting support
• Ugly, ugly, ugly

Acorn ★★★★★ ($29.99 until the end of May) has, as of v4, consolidated its lead over Pixelmator in terms of functionality and offers scriptability to challenge Photoshop. The most brilliant new feature of Acorn is its complete integration of layer “fx” (similar to Photoshop layer styles) and its Core Image filters. As in Photoshop you can modify layers non-destructively via layer effects, but unlike in Photoshop filter are simply UI candy for applying layer effects — so all filters are non-destructive and chainable. Acorn 4 also adds the ability — first seen in Pixelmator — to directly manipulate geometric inputs (e.g. zoom blur centering) when configuring filters.

And Acorn’s interactive brush-designer makes artists cry with joy.

Acorn lacks Photoshop’s ability to interactively create macros and apply them to batch processes — a powerful feature that many hardcore Photoshop users rely on; indeed there’s an entire industry out there of people trading Photoshop macros. Similarly, Acorn makes no attempt to deal with >32bpp images (beyond supporting Apple’s RAW importer). If you need either of these capabilities, Acorn won’t be enough for you.

• Improved UI over earlier versions
• Excellent non-destructive, chainable filters
• Highly scriptable (JavaScript, Python, Obj-C)
• No >32bpp support

Pixelmator ★★★★★ ($14.99) has the most straightforward UI. That said, while its UI is very attractive, I find it a bit too gimmicky. Forget about the physics-based “ropes” that join filter settings (e.g. zoom blur center) to the respective draggable widgets — that’s both cute and somewhat helpful — the tiny animated pictures with tiny captions for filters are impossible for me at least to make head or tail of. Compared with Acorn, Pixelmator has less powerful filters (and they’re destructive) and no scriptability. Like Acorn, it has no ability to do create macros or do batch processing.

I should also point out that all three of these programs now have fairly robust vector support, but none of them can touch on Photoshop’s tight integration with Illustrator and support for “Smart Objects” (essentially embedded and editable Illustrator documents that are rendered on-the-fly to whatever resolution you set them to). Of the three, Acorn seems to have the most refined vector support and Pixelmator the weakest.

• Simplest UI
• Gimmicky filter palette isn’t very usable
• Filters are destructive
• No layer styles
• No scripting
• No >32bpp support

Photographers

Finally, none of these programs is really suited for serious photographers. Photoline offers non-destructive RAW adjustments, placing it theoretically on par with (say) Lightroom or Aperture, but in practice it does a far inferior job of processing RAW files. Pixelmator imports RAW files, but it doesn’t seem to allow you to make any adjustments on the way in, which defeats the point of RAW-processing. Acorn provides a decent UI for the Apple RAW importer, but it’s still an import process rather than non-destructive editing. I spent quite a while tweaking some photos in Acorn a few blog posts back and was shocked at how easily I could produce far superior results in iPhoto or Aperture with a few clicks.

All three programs lack the ability of iPhoto, Aperture, or ACR to perform distortion-correction and non-destructive edits. It seems like there’s still a huge opportunity here for one of these applications (I strongly doubt it will be Photoline) to provide a seamless non-destructive workflow for Photographers (e.g. supporting “RAW layers” which can be masked and adjusted, but not painted on).

Conclusions

Pixelmator seems to have, at least for the moment, given up on competing on functionality and simply concentrated on making its program simple and attractive and cheap. At $15 it’s really a steal. Acorn, whether at $30, or its regular $50 price, is an amazing deal too. I’d recommend both, but as of Acorn 4, I can’t really think of any reason I’d want to use Pixelmator at all. Either way, you can’t really go wrong.

Photoline — which used to be my favorite Photoshop alternative — is more difficult to gauge. It’s the most expensive of the three, it’s by far the ugliest, but it’s also the most capable. It’s also cross-platform (and last time I checked one license works on both platforms). I’d suggest that unless you need one of the capabilities Photoline has which its rivals lack or you need something to use on both platforms (e.g. if you’re thinking of buying a Surface Pro) you pass on it.