Smart Filters: Photoshop Gets a Bit Smarter
If, like me, you are a fan of adjustment layers, you've probably longed for the day that Photoshop would let you apply other filters non-destructively. Well, with the introduction of Smart Filters in Photoshop CS3, that day is here.
The concept of Smart Filters is an extension of Smart Objects that were introduced in CS2. Graphics folks were quite excited by Smart Objects as a way to more seamlessly merge standard bitmap graphics that Photoshop has supported for years with vector based graphics that had generally been considered the domain of Adobe Illustrator and similar programs. But most photographers found it harder to find them generally useful. Smart Filters changes all that.
For those not yet familiar with Smart Objects, they allow you to encapsulate a layer or group of layers as a single object. You make one by selecting the layers you want to include via the Layers Palette and then right-mouse click and choose "Convert to Smart Object" from the pop-up context menu. There's an equivalent command on the menus at Layer >> Smart Objects >> Convert to Smart Object, if you prefer.
When you create one, whatever went into it gets replaced in the Layers palette by a new single Smart Object layer that represents what's inside. Your original layers are still there; it's just that you can't see them as individual layers anymore. If you double-click on your new Smart Object layer though, it will open up just as if you were opening a document from your hard drive. At this point Photoshop will show you a pop-up message explaining the details, but the gist is that you can freely edit whatever you want just as if you were editing a stand-alone document, and when you close and save it, it will be saved back inside the Smart Object layer in your original document. It's basically a document that lives inside a layer of another Photoshop document.
In many regards, you can treat this Smart Object layer just as you would any other layer. For example, if you use Edit >> Transform to shrink or distort it, your main document reacts accordingly. But if you double-click on the Smart Object to open it, the full original contents is still there, completely unchanged. The effects of shrinking it is purely an illusion done on the fly by the main document and does not change the layers that make up the guts of the Smart Object. As such, if you decide you overdid shrinking it, you can use Transform again to increase the side of the Smart Object with full resolution, just as if you had never overdone it in the first place. Imagine that: you can shrink a huge image down to a postage stamp and later enlarge it back to full size, good as new.
But as a photographer, I don't do too much with combining and changing elements in an image. And one thing you couldn't do to a Smart Object in CS2 was apply a filter to it. It deceptively seemed like you could, but when you tried, you were greeted with an ugly warning that to do so Photoshop would rasterize your Smart Object and thus the contents as individual layers would no longer be editable. Your Smart Object would get converted into a plain old dumb image layer in order to apply the filter. Bummer.
What Smart Filters in Photoshop CS3 bring to the table is a fix for this problem. Now when you apply a filter to a Smart Object, it creates a new Smart Filter layer and a layer mask to go with it. The integrity of your Smart Object remains intact. And better yet, the settings for this Smart Filter layer themselves remain fully editable, much as settings do for an adjustment layer. You can still double-click on the Smart Object to open it in order to edit the contents, but you can also double-click on the Smart Filter layer to open it in order to change its settings. Modifying the Smart Filter settings does not require opening the Smart Object being filtered either. Since the Smart Object and Smart Filter layers show on the Layers palette separately, you can edit either completely independently.
Smart Filters require a Smart Object to apply them to. If you go to apply a filter as a Smart Filter and haven't yet converted the underlying image layers(s) to a Smart Object, Adobe provided another way to do so via Filter >> Convert for Smart Filters. This does the same thing as the other ways of creating a Smart Object already described of course, but it is a thoughtful touch to add it here as well for folks like me that mainly use Smart Objects as a way to get at Smart Filters.
The standard restrictions still apply as far as which filters you can use in 16-bit mode. This means no Filter Gallery with Smart Objects in a 16-bit document. Interestingly, you can have an 8-bit Smart Object inside a 16-bit image, but you still can't apply 16-bit Smart Filters to it. But such filters as blur and sharpen are more useful to me at least anyway, and they work just fine in 16-bit mode. It's rather liberating to be able to sharpen an image and later return to change the settings used and have the image no worse for the wear and tear. Imagine applying a strong Gaussian blur to an image and later remove or lessen the blur and have the details re-emerge since they were in fact there all along, hidden inside your Smart Object and Smart Filter.
I'm guessing that both Adobe and third-party filter makers will add support for more filters in 16-bit mode in future versions. The Smart Filters in CS3 are just the start of a really good thing. The future looks to be even smarter.