The Spriters Revised Dictionary

[Gors]

Anti-Aliasing

---

Anti-aliasing, also known as antialiasing, antialias or AA for short, is a technique where you place intermediate pixels on strategical places in order to smoothen it.


Left: A pixel line. Right: The same line, with 3 gray tones of AA.

Usually, lines are anti-aliased on the corners and diagonal lines, where the irregularity is more apparent. Since pixelart deals with squares as the smallest graphical element, the places where "half a pixel" are painted are rendered with a lighter tone than the main color.


Diagram representing zoomed pixels on a screen. Notice that the pixels that are partially painted gets a lighter tone in order to render the line.

To successfully anti-alias a pixelart, you need to pick a color that is intermediate between the line and the background. So, if the line were to be red against a white background, the anti-alias lines should be lighter versions of red to properly blend the line.

Notice that overdoing anti-aliasing is not a wise idea and the more shades you create to smoothen, the more blurred your sprite will be.

Anti-aliasing a sprite

---

Due to its nature, anti-aliasing should be limited to details inside the sprite's outline than outside, in order to conserve readability, sharpness and use. Anti-aliasing outside the object should only be done if it's not supposed to move or be used in any other background.


Example with a Mario head. The first image is visibly rough and jagged. The second image smoothens the outside lines in a gray background, but if put against a pink background, the anti-alias pixels stick out, making it ugly. It is important to have this in mind when creating graphics for games, where characters walk and explore many terrains with different background colors.