Datum Identity & document system

Nobody sets
tracking by eye.

Datum is a calibration laboratory in Rotterdam. It certifies that other people’s instruments read true, which makes an unmeasured decision anywhere in its own identity a small contradiction. So the tracking is not a taste: it is a function of size, on one curve, and every piece of type in the system sits on that curve.

Client
Datum Calibration (invented)
Place
Rotterdam
Style
Swiss revival / neo-grotesque
After
Helvetica Now, 2019; the Inter and GT America house look
Type
Inter; JetBrains Mono for values
Curve
0 em at 16 px → −0.045 em at 128 px
01

The mark is the word and a datum line

A datum is the reference a measurement is taken from. The mark is the name sitting on one, with the trade information hung beneath at the two ends of the same width.

Datum CalibrationRotterdam
Full Datum
Compact Datum
Minimum · 9 mm Datum

Primary lockup and the two smaller cuts

The line
Always the exact width of the word, never wider and never inset. It is a datum, and a datum that does not line up with the thing it measures is worse than none.
Weight
The rule is two pixels at the full lockup and one below 20 px, because a two-pixel rule under small type reads as an underline.
Tracking
Set by the curve, like everything else. The word is tighter in the lockup than on a business card, and that is correct rather than inconsistent.
Never
Never a symbol, never a monogram, never the word inside a box. The laboratory has no logo, only a name set properly.
02

One curve, and nobody is off it

Move the size. Tracking is computed from it and shown as a number, because a house that issues certificates should be able to state the value rather than describe the feeling.

Calibration certificate

 

Size56 px
Tracking−0.0161 em
In pixels−0.90 px
Weight600

12 px to 128 px, left to right

The function
Tracking in em equals minus 0.045 multiplied by the size minus 16, divided by 112. At 16 px it is zero; at 128 px it is minus 0.045.
Below 16
The curve stops. Nothing under 16 px is tracked negative, because tight small type on a certificate is a legibility problem, not a look.
Why a curve
Large type has proportionally more space between letters than small type at the same tracking. The curve cancels that, so the colour of the setting is even at every size.
Mono
Values are set in the monospace at zero tracking. A number that has been optically adjusted is a number somebody has touched.
03

Three hairlines and nothing else

Every division in the system is one of three rules. There is no fourth, no dotted variant and no box: a border is four rules pretending to be an object.

Two pixels · structure Under the masthead, under a certificate header, under the datum in the full lockup. It says a section has ended.
One pixel · division Between rows in a table and between fields on a form. It says two things are adjacent, not that one outranks the other.
One pixel, acid · state The only coloured rule. It marks the row a reading failed on, and it appears nowhere that is not a failure.

The complete rule set

04

Grey, and one acid

Near-monochrome, because the documents are evidence and evidence should not be decorated. One acid does the work colour is allowed to do here: it marks state, never brand.

Ink#0A0A0BAll type and all structural rules. Not black: black on white vibrates at this weight.
Grey#67696ELabels, units and anything the reader does not need first.
Hairline#E2E2E5The one-pixel division. Never used for type at any size.
Acid#E3FF00A surface, not a text colour. It carries ink on top and marks a failed reading.
Acid, read#6E7A00The acid darkened until it can be read on white. Small type only.
Why one
Six departments would want six colours. They are not getting them: a colour that means one thing is worth more than six that mean nothing.
The pair
The acid exists twice on purpose. Setting 10 px labels in the bright one is the most common way this palette fails, so the darkened sibling is specified rather than left to be improvised.
05

One family, and the numbers in another

A grotesque for everything a person reads, and a monospace for everything an instrument produced. The join between them is where the system says what kind of thing you are looking at.

Display
600 · −0.038 emReads true
Heading
600 · −0.025 emUncertainty and traceability
Body
400 · −0.006 emEvery certificate states the measured value, the uncertainty, and the standard the measurement is traceable to. A reading without an uncertainty is an opinion.
Value
Mono 400 · 0 em21.4832 °C ± 0.0021 · k = 2
06

Applications

A report, a certificate, the site, a card and a door. Every one of them is the same three rules and the same curve, which is why they look like one house without a logo to tie them.

Annual
uncertainty
report
2026Datum · Rotterdam
Datum Issue 09

Report cover, 210 × 280 mm

Datum Calibration · Rotterdam Ines Broekman · Metrologist

Card, 85 × 55 mm

Lab 2 Temperature · 20 ± 1 °C

Door plate, the acid rule marking a controlled room

Certificate 4471 Traceable · RvA
InstrumentPT-100
Nominal21.5000
Measured21.4832
Uncert.0.0021
InstrumentPT-100
Nominal40.0000
Measured39.9910
Uncert.0.0026
Issued 12.03.2026k = 2 · 95%

Certificate, A4 landscape

Datum ServicesScopeContact

We tell you what your instrument actually reads.

Accredited calibration for temperature, pressure and mass. Two-day turnaround on the standing schedule.

Book a slotScope of accreditation

Website

07

Voice

A laboratory that hedges is useless. Everything written states a value, a limit or a standard, and anything that cannot be stated that way is not written down.

Say

21.4832 °C, uncertainty 0.0021, k = 2.

A number, its doubt and the confidence it is quoted at. All three or none.
Not

Highly accurate results you can trust.

No value, no limit, nothing anybody could check or dispute.
Say

Out of tolerance. The instrument reads 0.009 low at 40 degrees.

Bad news stated first, with the size of it.
Not

Some minor deviation was observed during testing.

Softens the one thing the customer paid to find out.
08

What breaks it

This look is currently the default for anything that wants to seem competent, which means it is imitated by people copying the surface. Four ways it goes, and the last is the one that empties it.

Datum
Tracking opened up for air Someone lets a headline breathe. The curve exists so that the colour of the setting is even at every size; one word off it and the page has two typographic systems in it.
Datum21.4832 °C
The acid used as type It is the brightest thing in the palette so it gets used for a number. On white it measures 1.1 to 1. The darkened sibling exists precisely so this does not have to happen.
A fourth rule weight A heavier rule gets added for a heading nobody could otherwise find. The three weights carry meaning; a fourth means the hierarchy failed and is being propped up.
DatumDatum
A second typeface for warmth The complaint is that it feels cold, and a serif or an italic arrives to fix it. It is a calibration laboratory. Cold is the product, and the warmth belongs in what the people say, not in a second font.

Datum Calibration is invented, built as a portfolio exercise in the neo-grotesque revival. Rotterdam and the Dutch accreditation council are real; this laboratory, its certificates, readings and staff are not, and no figure here should be read as a real measurement. The work is after the optical-size thinking in Helvetica Now, 2019, and the house look built on Inter and GT America that followed it. Those designers and foundries are credited as influences only.

Rule

Tracking is a function of size on one curve: zero at 16 px, minus 0.045 em at 128. Nobody sets it by eye.