A web designer has to be aware of aliasing and anti-aliasing, the problems associated with them, and the solutions to the problems. Aliasing is a situation in which a data location in memory can be accessed through different symbolic names in the program. Modifying the data through one name also modifies the values associated with all aliased names. If a web designer modifies the alias in the wrong way it could be difficult to understand, analyze and optimize programs. If a web designer is not careful in indexing the web site the effects of aliasing could cause visible jagged steps along angled or object edges, due to sharp tonal contrasts between pixels. The effects of the jagged edges will also be seen by objects that are bitmapped. A similar effect of aliasing not necessarily caused by a web designer is when a computer monitor, printer, or graphic file does not have a high enough resolution to represent the image or file.
A web designer is also well familiar with anti-aliasing with is the automatic and manual removal or reduction of stair step distortions in a computer generated image. A web designer sometimes uses and makes changes to what is called an alias which is a small file that represents another object used in another location on a disk. When changes are made to the alias by a web designer, if not done properly, the effects of aliasing is seen. A web designer can cure or subdue the affects of aliasing by using anti-aliasing techniques such as filtering or super sampling. When a web designer is working with a bitmap aliasing can be minimized by using the smoothing process of anti-aliasing which adds additional pixels to make the edges appear less jagged. The reason that a web designer has to be careful when using a bitmap is because bitmap images are made up of square pixels on a grid which makes a curve or diagonal lines have stair stepped pixels.
Anti-aliasing works with the way that our eyes see. Anti-aliasing adds shading along the curve to fool the eye into thinking it is seeing a smooth line rather a jagged bitmap. There are many reasons to use an alias images and text on the web as there are to anti-alias them. The arguments of whether one should or should not use anti-aliasing are great on either side that you find yourself. The pros and cons of anti-aliasing are this. On the up side, anti-aliasing makes fonts look smoother and makes rounded edges look round.
For some, type is easier to read as it looks more like what printed type should look like. For some, it just plain looks nicer or prettier. On the down side, Anti-aliasing tends to make small fonts become too fuzzy to read and sharp edges may be fuzzy. Anti-alias text when printed comes out blurred. Anti-aliasing is known as dithering in some circles. Companies like Microsoft offer different anti-aliasing software and tools. Windows XP for instance comes with a tool for anti-aliasing, called clear type which can be turned on or off by the user. Clear type is said to improve font display quality over traditional forms of font smoothing or anti-aliasing. It is said that it also improves readability on color LCD displays with a digital interface, such as those in laptops with high quality flat panel screens.