SYS364 DESIGNING OUTPUT SCREENS page 1 How Output Screens Differ from Printouts 1) Dimensions Pages can be of various sizes, and may be "portrait" or "landscape" orientation. Screens, however, are always "landscape" and are limited by the local hardware. In character mode, they are usually 80 characters wide and 24 lines deep, (132 X 27 mode is available but hard to read). This usually means that there will be more screens than pages – in width and length, and there must be a way to "navigate" from screen to screen (no such instructions are needed to urge the reader to turn the page). On paper, the reader has navigation control via page turning and by scanning large areas. Readers add information to paper reports using writing tools and highlighters. This ability is not usually available on screens without sophisticated programming -- does the customer need to "write" on the report? If so, paper might be a better option. On the other hand, screens can have "overlay" or "popup" windows which obscure part of the screen temporarily but then disappear. On paper, we rely on the reader to refer to separate publications (for instructions or policy or error messages). Furthermore, screens may have scroll bars, so that the user can slide up|down or sideways to get a temporarily larger view space. (Note that books with pages replaced paper scrolls for the sake of random access.) 2) Captions and Labels The commonly used columnar report ("tabulation") is less popular for screens than for printouts. Very often, each screen may show a single record, whereas on paper each page will show several records. In a tabulation, data is labelled with column headings which serve for all the lines on the page. On screen, it is more common to have each data element labelled with its own caption, which may be above it or to the left of it. A preferred style is the left-justified caption to the left of the left-justified data. 3) Colour For economy's sake, printouts are usually black on white; if colour is used, it will usually be "spot" colour or preprinted (not on computer) for things like logo, although limited use of computer-output colour is possible if the expense and slower printing is acceptable, especially for red negative values or highlighted exceptions. On screens, there may be full use of colour, including shading, patterns, etc. for no additional expense. Nonetheless, colours should be limited to restful combinations to prevent user eyestrain. Colour is for information, not entertainment. 4) Fonts The minimum font size for legibility is larger on screen (12 point) than on paper (10 point). Sans serif fonts are more legible on screen, but Roman-family fonts are more legible on paper. 5) Text Effects On paper, we are limited to changing the font or font size or font style (Bold, Italic, etc.), whereas on screen, we may have all of these plus: different colours for different kinds of data (caption vs. data), or colour blocks, or "inverse text" (swapping background with text colours). Please resist the urge to use "blinking" text. 6) Graphics On paper, graphics usually mean that artistic talent must be hired, and that reproduction may be crude--"jaggies" and limited colour. On screen, the resolution is already limited, but tools are available and easy to master to allow anything from simple drawings to realistic renderings or photos. 7) Interaction On paper, every reader sees the same report. On screen, however, the report can be modified by user identification or user interaction to give each reader a different report--level of detail, sort sequence, ... 8) Multimedia Readers may listen to a nice Bach concerto but the designer has little control here. On screen, however, sounds may be interspersed with sights and suitably coordinated. Sound effects can be used to reinforce error messages. When designing Output Screens, keep the usual Output Objectives and Design Principles in mind. Screens are different, but not that different! Output still needs to be purposeful, self-explanatory, attractive, focussed, balanced, harmonious, etc.