Course overview · Module 2 · Deep dive
Module 2 · Deep dive · 7 min read

Colour theory and typography for presenters

This isn't a course in graphic design — but presenting regularly without understanding the basics of colour and typography is roughly like driving a car without understanding why the brakes exist: it works, until it doesn't. Below: seven principles that explain what's actually happening when a slide looks professional — and why your laptop is lying to you about how it'll look on the projector screen in the meeting room.

The psychology of colour in a presentation context

There's a fair amount of literature on colour psychology that reduces everything to clichés: red = passion, blue = trust, yellow = joy. In a presentation context that model is too simple to be useful. What actually drives how a colour is perceived is the combination of hue, saturation and context — not hue alone.

Warm and cool are more productive categories than individual colours. Warm hues (red, orange, yellow) are visually perceived as moving toward the viewer — they create energy, urgency, presence. Cool hues (blue, teal, grey) recede — they give space, calm, distance. In practice: in a presentation to school leaders or a town council, a cool, muted palette works as a signal of seriousness and judgement. A presenter using bright red and strong yellow risks signalling salesmanship rather than expertise — regardless of what the slides actually contain.

Saturation is an underrated variable. High saturation (clear, pure colours) is energetic and youthful, but in a professional context can feel childish if used throughout. Low saturation (muted, almost grey hues) reads as mature and controlled. A pragmatic rule of thumb: choose background and text colours from muted tones, and save maximum saturation for the single word or single number you want the audience to remember.

Contrast — WCAG 4.5:1 is a minimum, not a standard

WCAG 2.1 (Web Content Accessibility Guidelines) specifies that text on screen should have a contrast ratio of at least 4.5:1 against the background to meet level AA, and 7:1 for level AAA. They're good benchmarks — but they're built for web browsers, not for projectors in half-dark rooms. The projector is, in practice, the enemy of colour: it washes out subtle hue differences, darkens dark areas and dazzles light ones. A text colour that hits 4.5:1 on your laptop screen may well drop below 3:1 on the wall.

The most robust advice is to design with high contrast from the start, and then test in the actual room with the actual equipment. If that's not possible: choose either a dark background with light text, or a light background with dark text — and avoid the in-between. Grey text on a white background is the most common contrast killer in presentation contexts. It looks clean on screen. On the projector it disappears.

Contrast doesn't only apply to text. Tables, charts and arrows that look distinct on your computer can collapse into a uniform surface when projected. The rule is the same: if you're unsure, the contrast is already too low. Tools like Colour Contrast Analyser (free, for Mac and Windows) let you measure the contrast value directly from your screen — use it.

Colour harmony — the theory is simple, the application requires judgement

Colour harmony describes how hues interact on the colour wheel. Three common systems: analogous — neighbouring colours on the wheel, giving a soft and cohesive feel (e.g. dark blue, mid blue, light blue); complementary — opposing colours, giving maximum contrast and energy (e.g. blue and orange); triadic — three evenly spaced colours, visually lively but hard to balance. Tools like coolors.co, Adobe Color (color.adobe.com) and hue.tools generate harmonies based on these systems — good as a starting point, but they require a critical eye to be adapted for a presentation.

For a presentation, complexity in the palette is usually a problem, not an advantage. A sophisticated triadic harmony with five hues can look impressive in a design portfolio. Projected onto a beige wall in a meeting room, by contrast, it looks like you couldn't decide what colour you wanted. The practical advice is simple: choose one background colour, one text colour and one — at most two — accent colours, and use them consistently throughout the presentation. Consistency creates the feel of a deliberate system, even if it's really just three colours.

A few highly saturated pairs are specifically worth avoiding when projecting: red and green side by side create a vibration effect that's uncomfortable for the eye — and on top of that, invisible to the roughly 8 percent of male audience members with red-green colour blindness. Strong blue on a dark background can be perceived as "glowing" and colder than intended. The rule is the same: test in the actual room.

Typeface families — why the choice isn't arbitrary

Three categories dominate presentation contexts. Sans-serif (without serifs — e.g. Helvetica, Inter, Arial) gives a clean, modern impression and reads well from a distance because the basic letterforms are uncomplicated. Probably the right choice for body text and running information on slides. Serif (with serifs — e.g. Garamond, Fraunces, Georgia) gives more character and editorial weight, but needs some sharpness to work at small sizes on the projector screen. Best used at large sizes for headings, or when the presentation should signal tradition, depth or academic seriousness. Slab-serif (heavy serifs with even thickness — e.g. Roboto Slab, Clarendon) is robust and projects well. Works well for individual punchy words or large numerical headlines.

Don't mix more than two typeface families in the same presentation. A solid combination is, for example, a sans-serif for text and a slab or serif for headings that should contrast with the running text. More than two families signals disorder rather than variety — even if the combination looks tempting in Keynote's or PowerPoint's typeface picker.

Type size isn't an aesthetic question, it's an accessibility one. The minimum readable size for a typical presentation environment is 28 points for body text, with 36–44 points for headings. If the text doesn't fit at that size, the problem is the amount of text — not the size. Cut the text, don't shrink the typeface.

Hierarchy via size, weight and colour — one axis is enough

There are three tools for visually distinguishing text levels: size, weight (regular, bold) and colour. The most common mistake is to use all three at once. A heading that's large, bold and in an accent colour sends three identical signals to the eye — it's underlined twice and triple-lined, and the result is overcharged visual energy that drains rather than reinforces.

The principle is to differentiate on one axis per text level. Heading versus body text: make the heading larger, but keep the same weight and colour. Want to highlight a word in the body text: make it bold, but keep the size and colour constant. Want to mark a number as the only thing the audience should remember: give it the accent colour, but don't make it larger or bolder than the surrounding text. A single deviation is signal. Three deviations on the same element is noise.

The system has a practical advantage: it produces a presentation that looks well-designed even if you don't have a design background. You don't need "an eye for it" — you just need to stick to one axis. And if you break the principle, do it with a clear purpose.

Spacing — line-height and letter-spacing on the projector screen

Line-height for body text in a web browser or a text document is usually around 1.2–1.3. That works at close range. But a presenter three metres away, with the audience another five metres beyond, needs more air between the lines for the eye to be able to separate them. The rule of thumb for slides: use 1.4–1.6 in line-height for body text. It looks airy on your screen — which is exactly what's needed for it to look normal on the projector screen. The same goes for padding and margins: generosity with empty space is a sign of control, not of you not knowing where to put the content.

Letter-spacing is rarely an active variable in presentation design, but it matters in one specific case: capitals. Text written in CAPITALS without extra letter-spacing feels jammed together and hard to read — the letters lack the natural gaps that lower-case letters create. Butterick's Practical Typography recommends 5–12 percent extra letter-spacing for text in capitals. In practice: if you write a heading in all caps, increase the letter-spacing until each letter can breathe. It isn't a detail — it's the difference between a word that looks professional and one that looks spammed.

Also avoid left-aligned text combined with maximum line length. Text that stretches from edge to edge of a slide forces the eye to travel back over a longer distance for each new line. Limit text columns to 60–70 percent of the slide's width — it gives air and improves readability from a distance.

When to break the rules

Design rules work as principles, not as laws. The most important question isn't whether you break them — it's whether the audience understands why. A slide that's deliberately overstuffed with text, typefaces and colours can be a powerful illustration of information overload: "This is what it feels like for your student to navigate a system without clear structure." The audience gets the point — if you put it in the right context. Without the context it just looks like a bad slide.

The same principle applies to deviant colour choices. A heading in all the colours of the rainbow can be the only right choice if you're communicating chaos, plurality of interpretations or fragmentation. A dark slide with a single white word can hit harder than four bullets with three sub-points each. The rule break has to be deliberate and clear — otherwise the audience reads it as a mistake, not as an active choice.

What separates a designer's deliberate rule break from a beginner's mistake is that the designer can explain why. Before you break a principle: tell yourself what you want the audience to experience. If the answer is "it looks a bit more dynamic" it's probably not a rule break — it's a mistake about to happen.

Sources and further reading