Uniformity is about the appearance of visual objects, such as screens, forms and controls. It implies that visual objects of the same type should look similar, namely, that they have common visual attributes and similar layout.
In panel design , uniformity implies that panel controls should look similar so that warning lights should have the same color or style of light and that the layout should not highlight any particular controls or warning lights.
Uniformity facilitates the learning of the user interface because it enables the quick recognition of new screens. After experiencing three to four screens of the same type, the user learns their common features. When the users first see a new screen of the same type, they recognize it by the common features. If these features are chosen and designed properly, then the recognition will be almost instantaneous. In panel design, uniformity simplifies maintenance, which helps in cost savings. In sound design, uniformity facilitates recognition of warning and alarm sounds.
Uniformity is the implicit assumption of many style guides. Many guidelines in common style guides are phrased as rules of absolute validity. Examples of such rules are:
Use grayish or silver colors for the background of screens and controls
Use standard serif fonts for printed text and sans-serif fonts for display
Use fonts of standard type and size
User standard beeps as audio feedback.
Uniformity may hamper attracting the users' attention to exceptional situations. If the new screen looks the same as the others, the users may not recognize that the situation is risky. If a warning message about an exceptional situation looks the same as regular feedback messages, then users may not recognize the warning. If the screen looks the same in routine interaction and in training, then users may not recognize when they work in the wrong mode.
Updated on 29 Feb 2016.