The Essentials of Technical Communication: Chapter 6

In this Chapter

This chapter focuses on the proper design and use of illustrations in technical writing. The chapter begins by presenting two questions to determine whether illustrations should be used. General guidelines for all types of illustrations are then listed. The chapter then covers each type of illustration. For each one, a bulleted list of guidelines and a few examples are provided. The chapter ends with a brief section about using illustrations ethically.

Illustration Basics

Before deciding to use an illustration, you should first understand what affect you want the document to have on the reader, and how illustrations will help you to achieve that goal. There are only two main types of illustrations: tables and figures. A table organizes information on grid, and is useful for summarizing information. All other illustrations are figures. Figures are useful for clarifying or emphasizing information.

General Illustration Guidelines

  1.       Illustrations should be simple so as not to distract the reader.

  2.       Illustrations should be chosen judiciously. Overly stylized graphs or simplistic clip art can be misleading or confusing to the reader.

  3.       Illustrations will increase the size of a document. Cost can become a factor in choosing Illustrations, especially when large quantities of print copies are needed.

  4.       Illustrations should be given appropriate titles.

  5.       Illustrations should be numbered so the reader can locate and reference them easily.

  6.       Illustrations should be referenced in the text of the document.  You should direct readers to the illustration before providing the explanation.

  7.       Illustrations should be placed as close to the relevant text as possible.

  8.       Illustrations should always include a source if you didn’t create it yourself.

Types of Illustrations

·         Tables:         Use to summarize information. A table should have relevant and descriptive column and row headings. Avoid making the table look crowed or overly complex.

·         Bar and Column Graphs:       Used to compare and contrast information. You should use descriptive axis labels and logical numerical units. Avoid dividing the bars too many times. Use color to distinguish different data sets, but avoid using color for decoration only.

·         Pie Charts:  Used to display relative size of different data sets. You should use no more than eight divisions; any more will make it difficult to comprehend the relative sizes of the slices. Place the largest slice in the upper right hand quadrant and arrange the remaining slices clockwise in descending order.

·         Line Graphs:              Used to show the amount and direction of change in the relationship between two variables. Label each axis and data series clearly and descriptively. Select the scale for each axis so that the slope of the line is representative of the actual trend.

·         Organization and Flow Charts:           Used to show the structure of an organization or the steps in a process, respectively.  The charts should be as simple as possible.  Use lines for an organization chart and arrows for a flow chart.  Use consistent designs, and avoid using design elements which convey no information. Try to make the chart as representational of the actual organization or process as possible.

·         Diagrams:    Used to show the relationship between objects. The diagram should be well labeled, simple, and relevant to the document. Avoid extraneous detail.

·         Photographs:             Used to show a subject in realistic detail. Crop the photograph to show only the relevant subjects. Use labels and captions to explain the picture. Avoid any editing of the photograph beyond cropping.  

·         Animations and Films:          Used to depict or simulate a process, operation, or incident. These should be simple and relevant to the document Editing out irrelevant material is all right, but avoid editing it in any way that changes the meaning or misrepresents the events being shown.

Illustration Ethics

It is important that, regardless of the type of illustration, you never distort information or mislead your reader in any way.