Visuals - Flip Charts

B.O.B. was looking for guidelines for how big visual aids should be for a small audience of about 20 - 25 people? I will be using several visual aids on a flip-chart and want to make sure the graphics and text is the appropriate size. The thread was Visual Aids and ran in December 2005

Rod advised:
It depends on distance rather than audience numbers, and it's not a matter of size alone - thickness, colour, contrast, and lighting intensity are also important factors. Not all members of your audience will have equal visual acuity.

Red/green colour blindness is the most common, so try to avoid combinations where confusion of these colours might cause problems.

Remember, you're presenting a speech and not administering an eyesight test!

With an audience of 25, the distance from your flipchart to the back of the audience is likely to be around eight metres (25 feet). For this arrangement, my recommendation is to use a character height of at least 40mm (an inch and a half). Avoid thin point markers. Make it easy for your audience to see and understand your visual aids.

For graphics, make sure that the important features are clearly illustrated and avoid non-essential detail. Visuals are support for your message - they're not the message itself. You can explain detail. For example, on a graph, label an axis with a large 'P' rather than the word 'Price'.

Keep each visual simple. Rather use a larger number of visuals with less information on each. Use different colours to differentiate ideas, items on lists, etc.

You can check the effect by looking at your flipchart under incandescent lighting from a distance of eight metres. Fluorescent lighting is closer to daylight and doesn't have the same effect on colours as incandescent lighting. Colours at the red end of the spectrum (reds, oranges, and yellows) sometimes become difficult to read. If you can't read your text easily and instantly, change size, boldness, and/or colour.

Once you've planned your size and chosen your markers, if you need to go 'live' on your visuals, set out your chart in feint pencil on the chart beforehand. It's then a simple matter to write boldly over the pencilled letters (which are invisible to your audience).

Rick added:
Standard fluorescent lights are just as different from sun light as incandescent. Incandescent lights are heavy in the red end of the spectrum and light on the blues. Fluorescent lights are the opposite. Warm fluorescent lights have more reds (but they aren't as energy efficient). Full spectrum fluorescent lights do a good job of imitating the sun.

I haven't seen any problem seeing reds and oranges if they are dark enough. (Dark yellow is brown.) Printed material under fluorescent lights could be had to read because they don't have a lot of red component. Actually, the human eye can see the least detail in the blue range because we have the fewest blue receptors in our eyes. However if this is causing a problem with your graphics, reread Rod's paragraph on simple and bold.

From the 1984 edition of the _Technical_Presentations_ manual, the Supplement says, text should be half (13 mm) and inch for every 10' (3 m) away the back row is. It also suggest no more than three colors except for pictures. It suggests limiting text to seven lines of seven words.

John F suggested if you have a marker that has a short edge and a long edge, use the long edge for writing as this will produce thicker lines that are easier to read.

Joy warned never, never use yellow or other pastel colors. They can't be read more than a few feet away.



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