A Page is the area that occupies the entire viewport of the screen during its current state. It organizes information while considering:

• Display technology.
• Navigation structures and interactions.
• Message display characteristics.

Mobile Display Elements

Message Display Characteristics

Legibility

Refers to the ease with which the elements (letters, numbers, symbols, etc.) can be detected and discriminated from one another.

• Font Design
• Upper/lower case
• Letter height
• X-height
• Stroke width/weight
• Letter/line spacing
• Contrast
• Illumination/luminance:

Brightness refers to our subjective perception of how bright an object is.

Luminance is the measure of light an object gives emits from its surface. Luminance is measured in different units such as candela (cd/m^{2), footlambert (ftL), mililambert (mL), and Nit (nt). Riggs (1971) notes that in starlight (luminance of .0003 cd/m}2) we can see the white pages of a book but not the writing on them. The recommended luminance standard for measuring acuity is 85 cd/m^2 (Olzak and Thomas, 1996). For text contrast, the International Standards Organization (ISO 9241, part 3) recommends a minimum of 3:1 luminance ratio of text and background. Though a ratio of 10:1 is preferred (Ware, 2000).

Remember that Luminance and Brightness are unrelated. For example, if you lay out a piece of black paper in full sunlight on a bright day, you may measure a value of 1000 cd/m^{2. If you view a white piece of paper in an office light , you will probably measure a value of only 50 cd/m}2. Thus, a black object on a bright day outside may reflect 20 times more light than white paper in the office (Ware, 2000).

Conspicuity: In addition to involving legibility, it also implies other display characteristics. It is nicely summed up by the notion of signal/noise ratio–the ease with which a given piece of information is detectable in the presence of other competing information.

• Design presentation:
• Spatial coding (grouping)
• Shape coding
• Color coding
• Temporal coding
• Size coding
• Pictograms, maps, images
• Attention/target value

Readability: In the display of messages we can affect another property of the message– its readability–by the actual choice of words, the sentence structure and the appropriate language(s).

• Communication
• Language
• Words
• Syntax
• Reading goals: Skim, scan, search, comprehension, evaluation

Pleasurability: (branding, compatibility, appropriateness, experience) Good user experience, consistent with the visual character of the surrounding architecture, appropriate ‘style’ to the activity, emotional and aesthetic benefits.

• Holistic viewpoint of ‘user’
• Based-on individual users’ interests, experiences, and activities
• User relevance and participation
• Text vs. subtext

Comprehension: Understanding the meaning of a given display so that an associated consequent course of action is both apparent and possible. Comprehension involves recognition as a necessary but not sufficient condition.

User Characteristics

Looking and Finding: Detection and Discrimination. Detection: Determining the presence of an object, target or symbol.

Descrimination: Determining that differences exists; discriminating between target objects and non-target objects is determining differences on the basis of which identifications can be made.

Identifying: Identification: Attributing a name or meaning to some object target or signal. Discrimination and identification are often parallel processes, but in psychological terms they make different demands of the presented information.

Recognizing: Recognition: Determining whether objects in the display have been seen before. Identification often accompanies recognition.