Another area where readability is factored into strategies for Web type is in the process of anti-aliasing.
Anti-aliasing smoothes out the jagged edges of a character, by blurring the pixels on the edge. Anti-aliasing generally increases the legibility of type, particularly large type, but it can blur small type and make it unreadable. It also increases file size and may introduce colors that are outside the Web palette.
Anti-aliasing refers to a number of techniques to combat the problems of aliasing in a sampled signal such as a digital image or digital audio recording.
- Aliasing displays the diagonal and curved lines in a graphical element as a series of small zigzag horizontal and vertical lines.
- Anti-Aliasing is a technique that reduces or eliminates aliasing by shading the pixels along the border of a graphical element.
- Certain adaptations of anti-aliasing can enhance both the legibility and aesthetics of on-screen type, though not in every case.
To smooth the edge of a simple black-on-white character on the screen, a program like Photoshop creates 16 to 20 intermediate tones of gray to fill in the steps.
From normal viewing distances, the type will look smooth.
Type sizes of 14 points and up usually can be anti-aliased quite successfully. Around 12 points, it depends very much on the weight and design of the typeface. Below that, it ismuch better to use a properly designed screen font without anti-aliasing.
- Aliasing and Anti-aliasing
- Regular (Aliasing) and Anti-aliasing comparisons