A little Thing Called Anti-Aliasing

Posted on Tuesday, September 09, 2008:: 1213 Views

Have you ever received a print from a lab which contained text and found that your image looked great but the text looked jagged and terrible? You were pretty sure the resolution was correct (since the image looked fine), and on screen everything looked OK. So what happened to the text? Chances are you neglected to apply a function known as anti-aliasing to your text. Put simply, anti-aliasing smoothes out the edges of your text, or at least gives the illusion of doing so. What really happens is a bit of trickery on Photoshop's part.

If we look at a close up of a character that's had anti-aliasing applied to it and one without, we see the digital tomfoolery for what it really is. In the image below Photoshop actually added pixels to the detail on the left in an attempt to give the appearance of a smooth edge. You can see the varying shades of grey used to pull off this feat. The detail on the right is composed of nothing but black pixels forming the jagged, curved edges. The beauty of this miraculous, mathematical magic trick is that Photoshop only adds pixels to the outside of the character so no detail is lost and the shape remains intact.

 

In the image below you can see the effect at a smaller size.

 

Now, back to the issue of your text appearing fine on screen. Most computers - this goes for PCs and Macs - have automatic smoothing, or aliasing applied to all on-screen text. So until you actually print your image, you might never know that you have anti-aliasing turned off in Photoshop. To turn it on, select your type tool, and in the option bar at the top of the screen you'll see a little "aa" with a drop down menu available. In said drop down menu you'll find different methods of anti-aliasing; None, Sharp, Crisp, Strong and Smooth.

 

So how do you know which one to choose? Well, it's mostly personal preference, but here is a brief description of what each method does. None is pretty obvious so we'll skip that one. Sharp will give you the sharpest (not necessarily the smoothest) type. Crisp is slightly less sharp than Sharp and a hair more blurred. Strong will make the type slightly heavier. Smooth will make your type smoother but slightly more blurred. It basically depends on the font style you are using. With script fonts you'll probably want them to be a little sharper. Serif fonts could benefit from some smoothing. You might want your sans serif fonts to be smooth and a little heavy. Or, you might just want to set the darned anti-aliasing on smooth and never worry about it ever again. The decision is really up to you but here is a little guide to hopefully help out your decision making process.

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