Why you should avoid 10-point or smaller type when highlighting your document.

Title: The ONE thing to avoid when highlighting your document (and how to do it right)

Let me ask you a quick question: when you want someone to notice a key idea, what do you reach for first—bold text, a splash of color, or a tiny size that almost disappears on the page? If you picked “tiny,” you’re not alone. But here’s the truth that every smart writer should tuck away: never use 10-point or smaller type to highlight your document. Small text loses impact. It makes readers squint, skim, and sometimes miss the very point you want them to grasp. And that defeats the whole purpose of highlighting, doesn’t it?

In the world of technical communication, highlighting is the flashlight that guides readers through complex information. It’s not about making things look fancy; it’s about making meaning clear and accessible. The moment you let tiny type creep in, you’re risking clarity. Let’s unpack why and how to highlight in a way that serves readers—every time.

Why highlighting exists in the first place

Highlighting isn’t just about grabbing attention. It’s about structure and ease. A well-highlighted document:

• Draws the reader’s eye to important ideas, definitions, and warnings.

• Creates a predictable road map, so someone can skim for the gist and still find exact details.

• Supports comprehension for varied readers, including those who are new to the topic or who read in a second language.

Think of it like signage in a busy airport. The arrows, color blocks, and bold headers help you move quickly from check-in to security to your gate. If the signs were small print and dull, you’d miss connections—and so would your readers. The same logic applies to technical documents: legibility and legibility alone keep readers moving in the right direction.

The big no-go: tiny type (the reason to avoid it)

Here’s the core rule in plain terms: don’t highlight with 10-point type or smaller. There are several tangible reasons:

• Reading fatigue. Small text forces the eye to strain, which slows down reading and makes mistakes more likely.

• Reduced contrast. Tiny letters often pair with thinner strokes, which reduces contrast and makes words harder to distinguish.

• Accessibility gaps. Some readers rely on larger text for quick scans or screen magnification. Tiny text blocks can exclude them.

• Slower cognitive processing. When the message itself is hard to see, readers spend energy deciphering rather than understanding.

If you want your key points to land, give them room to breathe. A highlighted sentence in a readable size feels like a shout in a crowded room—clear, intentional, and persuasive. A tiny highlight feels more like a whisper that gets lost.

Smart highlight strategies that actually work

Let’s trade fear of bold styling for a practical, reader-friendly toolkit. Below are reliable moves you can adopt—without turning your document into a carnival of formatting.

1. Use dramatic typefaces, sparingly and purposefully

Yes, contrast is your friend. A bold weight or a distinctive font for a headline can signal a boundary in the text: this is important, this is a definition, this is a warning. The key is restraint. If every heading looks dramatic, nothing stands out. You want a hierarchy that feels natural, almost intuitive. The reader should say, “Oh, this bit is different, so it matters,” not “What happened to the font—is this the same document?”

2. Color with intent, never as decoration

Color can flag ideas, but it must pass muster for readability. Choose a small palette and stick to it. For example:

• Use one accent color for emphasis (not every sentence).

• Ensure high contrast between text and background. If your color is light, pair it with a dark text color.

• Be mindful of color-blind readers. Test how things look in grayscale or with a color-blind simulator.

• Pair color with another cue, like bolding or a short heading, so the point isn’t color-dependent alone.

A practical tip: color can guide, but contrast saves you when color fails. In a print handout or a PDF, a bright yellow highlight may look cheerful on screen but disappear in print when the ink is pale. Always check both media.

3. Size matters, but not the way you think

The core warning is simple: avoid 10-point or smaller for highlighted bits. Beyond that, aim for typography that supports scanning:

• Body text: generally 12-point or larger for print; web text around 16px to 18px is common for comfortable reading.

• Headings and subheadings: give them clear scale differences—this is where readers expect to see the map of your content.

• Bullets and callouts: these can be a touch larger than body text, but not so large that they compete with headings.

For many documents, a readable baseline is the difference between someone absorbing your information and someone glossing over it. People don’t want to struggle to read a key point; they want to skim quickly and still get the gist.

4. A clean typographic hierarchy makes your point pop

Hierarchy is like a well-organized toolbox: different levels for different tasks. Use:

• Heading levels to structure sections.

• Bold or semibold weight for emphasis within a paragraph.

• Short, punchy callouts for warnings, tips, or definitions.

The goal isn’t to shout; it’s to guide. When the reader sees a consistent pattern, they know where to look for what matters, even if they’re rushing.

5. Spacing, margins, and line length are part of highlighting

Don’t overlook the space around your highlights. Adequate line height (1.4–1.6 for body text) and comfortable margins make highlighted content breathe. Line length matters too: aim for roughly 45–75 characters per line. If lines are too long, readers chase the end of the line; if too short, they’re interrupted by frequent wraps. Both disrupt the reader’s focus.

Where these ideas live, depending on format

Different outputs call for slightly different tactics, but the core rules stay the same.

• In PDFs and printed documents: rely on print-friendly typography. Use a style guide to lock in font choices, sizes, and color usage. A simple “Heading 1 = 16pt bold; body = 12pt; highlight color = blue” rule goes a long way.

• In word processing tools (Word, Google Docs): embrace the built-in styles. Styles enforce consistency and make it easy to adjust the whole document later. A quick accessibility check can reveal if the highlights align with readability standards.

• On websites or digital manuals: prioritize contrast and responsive sizing. Remember that users resize text, switch devices, or view in dark mode. Test your highlights in different themes and screen sizes.

A quick audit you can do right now

If you want a practical way to verify your highlights, try this light checklist:

• Size test: Are all highlighted items at least 12pt (print) or 16px (web)? If any are smaller, bump them up.

• Color test: Do your highlighted elements meet contrast requirements? Do they still read well when viewed in grayscale?

• Hierarchy check: Is there a clear path from top to bottom? Do headings and callouts stand out without crowding the page?

• Read-aloud test: Read the section aloud. Do the highlighted bits feel natural when spoken, or do they sound forced?

• Accessibility check: If you have a readers’ device or a screen reader, does the structure still make sense when heard rather than just seen?

A few tangents that help and don’t derail

Color and typography aren’t just aesthetics; they’re communication tools. You might have seen signage in a hospital that uses bold red for warnings or a construction site with bright orange for cautions. That’s not a vibe—it’s a system. Readers subconsciously learn that certain colors and font weights map to specific meanings. When you respect that system, you reduce cognitive load and boost comprehension. And yes, you may even make your document feel a touch more human, more accessible, more considerate of someone who’s reading during a busy day.

Real-world tools and whispers of wisdom

• Microsoft Word and Google Docs: Use built-in styles and review accessibility options. The “Styles” pane is your best ally for consistent heading sizes. The accessibility checker is not just a box to tick—it’s a practical sanity check.

• Adobe InDesign: Great for long manuals where separation of content and presentation matters. You can set up a robust typographic system with master pages, ensuring highlights stay consistent across chapters.

• Web tools like WebAIM or Contrast Checker: If your document lives on the web, you’ll want to guarantee legibility for all readers. Small color tweaks can make a world of difference.

Common missteps to side-step (so your highlights stay helpful)

• Too many highlights. If everything’s important, nothing’s important. Use emphasis selectively.

• Mixing too many colors. A rainbow of highlights is visually noisy. Pick a couple of colors and reserve them for distinct signals: definition, warning, tip.

• Ignoring accessibility. High contrast isn’t optional; it’s a baseline in many organizations. If readers can’t discern the text, your message gets lost.

Bringing it back home: highlight for clarity, not for flair

Here’s the bottom line you can take into your next document: the most effective highlighting serves clarity and accessibility. It’s not about making the page flashy; it’s about making it legible, scannable, and respectful of your reader’s time. Tiny text betrays the very purpose of highlighting. It’s asking readers to work too hard, to strain for something that should be obvious.

If you’ve ever rewritten a paragraph because the highlighted sentence was too hard to read, you know the value of the right size and the right emphasis. Highlighting should feel like a guiding hand, not a demand on attention.

A closing nudge: treat your reader as a person with a busy day

Sometimes the simplest question helps: would I feel confident finding this information in a pinch? If the answer is yes, you’re on track. If the answer is no, that’s your cue to adjust. It’s fine to be deliberate about emphasis, to let typography carry weight, to use color with purpose. The goal isn’t to shout; it’s to illuminate.

So next time you format a document, check the size of your highlighted bits first. If any are 10-point or smaller, raise them. Then layer in bold for emphasis, a thoughtful color cadence, and clean hierarchy. Your readers will thank you with quicker skims, better retention, and less fatigue.

A final question to carry forward: when someone glances at your page, do they immediately see the key ideas, or do they have to hunt for them? If you can answer yes, congrats—you’ve turned highlighting into a reliable ally, not a last-minute flourish. And that’s the kind of clarity that makes technical writing truly useful.