To open this frame in its own Window, click here.
The scientific brilliance of our talks and posters at national and sectional meetings is unconformably overlain by their increasingly poor stylistic quality. The two main causes are lack of an "abstract" in the introduction and brazen technological sophistication (computer-drafted slides) or lack of it (overhead transparencies).
The two most important guidelines for such presentations are KISSing (U.S. military for "keep it simple, Stupid") and legibility. KISSing is an acquired skill. KISSing and the production of legible slides require significant preparation time (planning).
Organization. The most important KISS factor in a talk is an abstract in the introduction. Landes ((1951) stressed that printed articles require an informative abstract, not an expanded table of contents. An abstract (or "take-home message") is more important in talks because most of those in the audience either have limited prior knowledge of the topic or have sensory overload from other talks. Additionally, too many talks expire without a conclusion. To KISS well, "Tell'em what you are going to tell'em' tell'em; and then tell'em you told'em."
Illustrations. Reams of highly technical advice have been written about illustrations, but Gallagher (1965) said it all with his 12:1 rule: whatever the longest dimension of your drafted illustration in inches (no matter if it is with colored pens on butcher's paper or on the screen of a computer), step back that number of feet to preview your slide. If you can read it from that distance, so can an audience. Although the lantern slides of Gallagher's day are obsolete (and you probably can "go metric"), his advice still applies to 35 mm slides and overhead projections. A useful variation of Gallagher's technique is to look at a slide without any magnifying device (except your glasses). A more sophisticated mathematical formula: visibility 1/D2; to confirm this, view your illustrations from the last row in the hall!!!??!! An obvious cure would be to require all speakers (especially those using overhead projectors in the front of the hall) to lecture from the back of the hall!
Slides copied without modification from illustrations in printed articles and most view-graphs used on overhead projectors violate the 12:1 rule and KISSing. View-graphs for overhead projection can be improved somewhat by simply enlarging them on a photocopy machine so that the image fills the horizontal dimension of the screen. Even so, overheads commonly are illegible for more than several people sitting around the same table (in which case, each person could be provided with a photocopy instead).
Overheads have the additional disadvantage of being distracting, especially if part of the talk uses 35 mm slides and then switches to overheads. In addition, the rustling of the overhead illustrations and the interleaved papers is annoying.
Colored pencils and pens can be superb technologies. A slide does not have to be beautiful or computer-drafted. Instead it has to be legible. To be legible, violate neither KISS nor Gallagher. If a complex picture is required (as is commonly the case in the earth sciences), give multiple KISSes by showing a series of slides (e.g., various portions of a map that would otherwise violate 12:1, or successive overlays in successive slides); that is, each slide is a KISS.
For the largest possible image on a screen (and to avoid the distraction of refocusing), design all art work for every slide or overhead to be elongate horizontally by 3:2, which is the approximate ratio of a slide. Likewise, fill the computer screen horizontally with your illustration, not with titles (that you should present orally) and not with fancy borders that only diminish the size of the illustration.
Even if you are a computer wizard, do consult your friendly visual arts expect; do solicit suggestions. When the time comes to photograph the artwork (to make slide), be there to be sure that the correct path of the artwork is photographed, the exposure best illustrates your point, and the largest possible image is photographed (to beat 12:1). Do not ready a slide that is mainly text. The audience can read silently faster than you can aloud; thus, your voice causes interference. Some in the audience might even be insulted that you consider them illiterate.
In illustrations consisting mostly of text, avoid using entirely upper-case (capitalized) letters. People read faster (recognized a word more easily) by the variation in lower-case lettering. A note of caution: lower-case lettering more commonly violates 12:1. "I know that this slide is too dark and hard to see" is inexcusable. Any processing laboratory can produce the correct exposure from a dark slide.
Poster Session. Do have an abstract. Poster sessions are really
slow-motion slide shows (using the artwork and captions instead). Avoid more
than a few lines of text in any one caption or item; that is, have more visuals
than text. Poster sessions permit some (but not total) avoidance of KISSing
and Gallagher. For text and captions use lettering that can be read from a meter
away. For excellent advice on poster sessions, heed Connor (1991).
Remember, there is no profit in making good work look bad - not even with a computer or overhead projectors. Slides are the appropriate technology; overheads are not. The drafting and photographing of adequate slides require that time be spent in planning and preparation (which is why overheads usually are disasters). The required amount of time depends on the skill of the presenter. Most of us need to dedicate as much time in preparation as the length of the talk (in minutes) times the desired number of people in the audience. Talks should have an abstract and slides should be legible. KISS Gallagher or Connor; and follow the directions that GSA distributes to speakers.
References Cited
Connor, C.W., 1991, The poster session: A guide for preparation (Geological Society of America Speakers Information, 1991 Annual Meeting): U.S. Geological Survey Open-File Report 88-667.
Gallagher, D., 1965, On lantern slides: Geological Society of America Bulleting, v. 76, 1081-1082.
Landes, K.K., 1951, A scrutiny of the abstract: American Association of petroleum Geologists Bulletin, v. 35, p. 1660.
Eric C. Cheney
University of Washington
Seattle, Washington 98195-1310
Click here to return to EPS490 Index Page.
Earth & Planetary Sciences 
Home or our 
Index page