nanalLabs BlogSearch "lab notebook writing tool" or "lab notebook pen" and you'll mostly find a single line of advice: use ink that doesn't erase. What people actually run into after that is more specific — is pencil really banned, why exactly are erasable pens a problem, can you highlight for emphasis, does the ink have to be black. This post pulls together what Korea's National R&D Research Note Guideline and several university research-office manuals require on each point. Specific requirements can vary by institution and project, so verify against the source text and your institution's own policy before applying any of this.
Why "any ballpoint" doesn't cut it
A lab notebook carries evidentiary weight for exactly one reason: what it says can be verified later as what it actually said at the time. Every writing-tool rule exists to serve that single purpose — physically ruling out the possibility that an entry disappears on its own, or gets altered without leaving a trace. So the requirement boils down to one thing: once written, it can't be erased or changed. Pencil, erasable pens, and correction fluid are all banned for the same reason.
The real problem isn't pencil, which is obviously erasable — it's the "friction" (heat-erasable) ballpoint that looks like an ordinary pen. Rub it with the attached eraser, or apply heat from something like a hair dryer, and the ink turns colorless without a trace, and there's no way to tell from looking that it's not a normal pen. If a counterparty in an audit or a patent dispute later raises "wasn't this page originally something else," you don't want to be in the position of having to prove ink chemistry to settle it. The simplest fix is to never let an erasable pen into the lab in the first place.
What's allowed, what isn't
| Item | Allowed | Banned | Why |
|---|---|---|---|
| Writing tool | Oil-based ballpoint, non-water-soluble gel pen | Pencil, mechanical pencil | Can be physically erased |
| Erasable pens | — | Friction-type (heat-erasable) ballpoints | Heat erases the mark without a trace |
| Ink color | Black (preferred), dark blue | Pencil gray, erasable colored ink | Copy/scan legibility, distinguishing tampering |
| Correcting an entry | Strike through with two lines, sign and date | Correction fluid, correction tape, stickers | The original entry disappears entirely |
| Emphasis | Highlight or box around text already written in black | Highlighting over the letters themselves | Overwritten text can vanish on a scan or photocopy |
| Paper | Bound notebook, water/wear-resistant stock preferred | A loose-leaf binder you can add to or pull pages from | Pages can be inserted or swapped to reorder entries |
The mechanics of how to correct an entry are its own topic; the writing- tool rules covered here are really about picking a tool that lets you make that correction properly in the first place.
Why is black preferred over other colors? Most manuals allow blue too, but black is recommended first because it holds contrast best when copied, scanned, or faxed in black and white. Lab notebooks often get submitted as copies rather than originals — for a patent filing or a tax-credit review, say — and light ink can come out faint or vanish entirely in a copy. The paper itself should resist moisture and oil too, since spilled reagents and wet hands during an experiment are common.
When (and how) to use a highlighter
Emphasis itself isn't banned — the issue is sequence. Write the content in black first, then add a highlighter box or underline on top of it, and you're fine. Do it the other way — highlighting over the letters, or writing the body text itself in colored pen — and you have a problem. Highlighter ink can fade over time or blend into the background on a scan, and colored-pen text can disappear entirely on a black-and-white copy. Emphasis should always sit on top of black text that's already fixed on the page, not replace it.
Electronic notebooks don't have a "pen"
Move to an electronic notebook and this rule takes a different shape entirely. What the writing tool does on paper — make an entry impossible to quietly change — an electronic system does with an e-signature and a timestamped edit log. That's the same "tamper-evidence" requirement covered in what electronic notebooks are actually required to do. Switching to electronic doesn't free you from the writing-tool rule; it moves the same requirement from a physical mechanism ("ink that won't erase") to a logical one ("a system that logs every edit"). Paper or electronic, the goal is identical: make it impossible to quietly change when something was actually written.
A checklist before you stock the lab
- [ ] Is an oil-based ballpoint or non-water-soluble gel pen the default
writing tool?
- [ ] Has the team been told not to use pencils, mechanical pencils, or
erasable (friction-type) ballpoints for notebook entries?
- [ ] Is correcting an entry done with a two-line strikethrough instead of
correction fluid or tape?
- [ ] Are highlighters and colored pens reserved for emphasis on top of
black text already written, not as the primary ink?
- [ ] Is the notebook bound rather than loose-leaf (and if electronic,
does it automatically log an edit history)?
It looks like a small rule, but in an audit or a dispute, the writing tool is often the first thing that decides whether a page reads as original. Standardize on one set of tools and you avoid having to defend the authenticity of individual pages one at a time later.