Adding Image Effects to Preview in OS X

Preview is a fairly decent image viewer and converter, but what it could really use to make it a good go-to image editor is some basic image processing effects. Obviously you can’t turn it into Photoshop, but the ability to do some kind of processing would be a good thing.

In this article we will be using Automator to harness the Quartz Effect engine as a preprocessor for Preview.

Adding image effects to Preview is actually a simple three-step workflow with Automator. Open Automator and make an Application.

As with every image processing job, it’s prudent and just plain good practice to operate on a copy of your image. If you save your treated version over the original, you won’t be able to get it back, so our first move must be a backup.

So, drag in a “Duplicate Finder Items” action. If you can’t find the action, as always with Automator, type the first few letters of the name into the search bar and you will find it easily.

Drag in a 'Duplicate Finder Items' action.

This will, as the name suggests, make a copy of the image you feed to it and save it to the same location as the input file appended with the word “copy.” From now on, all actions will act on the copy of the image.

So having made sure we are working on a copy, we need to start applying some effects.

Next drag in an “Apply Quartz Composition Filter to Images” action. This is a powerful action which uses the OS X built-in quartz image engine to apply a suite of real-time effects to images and videos.

Drag in a 'Apply Quartz Composition Filter to Images' action.

You will get a warning dialog about how this action will alter image files passed to it, and it will ask if you want to add a “Copy Finder Items” action. Just click “Don’t Add,” as you already took care of this. Nice of them to care, but you got this.

Before you move on, there’s one more thing to do, click the options button on this action and check the “Show This Action When The Workflow Runs” box. This is important as this will pop the Quartz command box up allowing you to select a filter and adjust slider controls for each effect. Also, if you set a specific effect in this box at this stage, that will be the default effect when the box pops up.

And finally the last step in this workflow is to send the results to Preview so you can crop, resize and do any of the processing you would usually do in Preview.

Drag in an “Open Images in Preview” action. This opens the freshly effected picture so you can finish off any processing you want to do, like resizing, cropping, converting to another image format and so on.

Drag in a 'Open Images in Preview' action.

Once you have this action in place you are done. Save the application as “Effect to Picture” to the Applications directory. Also you can drag a copy of it to the dock for easy access.

All you have to do to make this work is drag a picture onto the “Effect to Picture” Application icon in the Dock.

Drag a picture onto the 'Effect to Picture' Application icon.

The app will make a copy of the picture and save it to the same location as the source. Then it will open up the Quartz control panel.

Apply Quartz Composition Filter to image files.

This works a bit weirdly in Yosemite (or at least in my version, your mileage may vary) whereby the panel opens small and you have to drag it open enough to see the controls. I suspect Automator is due for an update soon.

(Also I’m sure there is probably some Applescript you can use to make that happen automatically. It works well enough for the purposes of this tutorial, so we’ll let it go for now.)

Select the effect you want, or go with the default.

The picture is effected, saved and then opened in Preview. So in one drag and click you can go from this:

In one drag and click you can go from this...

to this or this:

Final result - comic filter.

Final result - old filter.

Obviously, this process is not terribly elegant, but hey, it’s a bolt-on, and as a basic image filter, which is available on demand, it’s not too shabby. And some of the effects are actually surprisingly high quality considering how little processing time they take up.

Try this out for yourself, and let us know how you get on in the comments below.