Principles of the Wristwatch as Instrument

The first concern of any instrument watch is that it be designed to show the necessary and relevant information to the task at hand. Second is that it must show this information in a way that is clear and easy to understand. Any functions should be simple and intuitive to operate. Finally, the instrument should be robust enough (mechanically, &c.) to function reliably in the field, but not so robust as to become cumbersome.

I’ve separated the designs into four categories based on function:

1. Time only.

2. Diving.

3. GMT.

4. Chronograph; general purpose and specialist.

The issue of legibility can be broken down into the following issues:

1. High contrast (in terms of colours, fonts, etc.).

2. Visual differentiation of data modes/forms (placement and relationships of outputs).

3. Clarity (lack of irrelevant clutter, and the lack of glare).

4. Adequate size (of dial, hands, and markings on dial and bezel).

While every separate type of information should be presently clearly and in contrast to other forms of information, one (as the user of the instrument) must also do ones own part in focusing on what it is one needs to acquire. What I refer to as “directed focus” is simply illustrated by the following paraphrase of an old
apocryphal tale:

Our story opens at a practice session of four archers from the same Dojo. The Master of the Dojo presented a challenge to his students, to strike the small painted eye of a carved wooden fish placed atop a pole at the opposite end of the training field. Each student lined up one by one,
launching a single arrow at the distant target. When all bows were lowered, three
arrows stood from the side of the fish, and one from the center of the eye. The Master asked each of his students what they saw when they took aim and loosed
: “A fish.” “A fish.” “A fish.” And finally, “An Eye.”

The Watches:


1.The Mark XI: The simplest and most essential information displayed by the wristwatch is the time, specifically the hour, minute and second of it. Here we see the each element that contributes to legibility clearly demonstrated: White on black provides high contrast;
Arabic numerals provide clarity and easy recognition; tritium provides visibility in low light and darkness; hour, minute, and seconds hands are all shaped differently, preventing confusion and errors. The only unnecessary “clutter” is the brand name.

1977 Rolex Submariner, British Military

2.The Submariner: You will note first how the dial markings consist of batons at the cardinal 3, 6, and 9, an inverted triangle in the military fashion at 12, and dots to mark the other hours. This is in sharp contrast to the
Arabic numerals, silver on black, on the bezel. I find it to be essential when employing a functional bezel, that the dial and bezel use different marking to avoid mode confusion — this is perhaps the clearest example.

1958 Rolex GMT Master

3.The GMT Master: As is clearly evident, the design of this watch incorporates and builds upon the the earlier design of the Submariner. The bright colours of the bezel make it, and the information it relates, distinct from the dial. Note also how the dual-colouring differentiates day and night on a 24-hour counter that is often non-intuitive to those accustomed to 12-hour time displays. The red GMT pointer likewise differentiates itself from the white hour, minute, and seconds hands.

1967 Omega Speedmaster Professional

4a.The Speedmaster: The general purpose chronograph balances its two primary functions, current time and time measurement, by providing large index hour markers, small indexes that serve double duty for time and chronograph minutes, and small
Arabic numerals on the sunken chronograph subdials. Additional chronograph optimization is provided through the utilization of the
fixed bezel ring, which features one of four replaceable scales Pulsometer, tachymeter, telemeter, and a decimal scale. The thinness of the supplementary ring, as well as its colour, prevents it from impinging on the neutrality of the large primary dial.

1967 Breitling Navitimer

4b.The Navitimer: Specialized for aviation with an integral navigation computer, this chronograph presents a complex and confusing appearance to someone looking at it for the first time. Despite its apparent
complexly, the dial though smaller, is actually as free of unnecessary clutter as the Speedmaster’s above it. When focusing upon the time, the computational bezel-ring that contrasts with the dial fades into a blur. The white on black hand and hour markers stand out clearly from the black dial, and alternately when focusing on the subdials, with back hands and numeration on a white background (much like a railroad watch) allow them to stand out isolated on the dial. Everything is high contrast in an alternation of black and white. With regular use, the mind reflexively focuses when:

Reading time: Black dial, white hands and markers.

Reading totalizers: White dials, black hands and numerals.

Reading computer: White ring, numerals graduating from black on white to white on black.

Other design factors:


The degree of water-resistance required in the design of any instrument in necessarily determined by the environment in which the instrument is expected to operate. The structurally complex Navitimer for example, a pure aviators watch for use in a pressurized and environmentally controlled cockpit, has no water-resistance. Alternately, the SCUBA divers Submariner requires 200 meters of water-resistance simply to be expected to function in the hostile undersea environment.

Case materials and design

While gold cases are not unknown for certain specialized types of instruments — like pulsometers for medical doctors, stainless steel with its almost care-free corrosion resistance and “toughness” (adequate hardness without brittleness) is the near-universal material of case manufacture for instrument watches. Also nearly universal is the use of the screw back. Though is does increase the thickness of the overall watch, its simplicity, strength, and superior seal again environmental contaminants make it preferable to snap and screwed on backs. Finally, hesalite or other acrylic polymers offer the impact resistance desirable for the domed crystals of wristwatches expecting rugged use in the field.

Screw-down crowns are standard on watches with high water-resistance (50m or greater), and generally serve to
immobilize the crown and prevent lateral pressure on the seals by the stem. Some screw-down crowns also incorporate extra gaskets for even greater security. Crown and pusher guards protect protruding controls from damage or entanglement at the cost of reduced ease of access, and are thus a design compromise only selected if the hazards outweigh the requirement for convenience.

Extra protection from magnetic fields is another function of case (and dial) design, and its necessity like water resistance is determined by the expected theatre of operations and the threats therein. Two of the above watches incorporate varying degrees of protection. The Mark XI encloses its movement in a soft-iron “Faraday cage,” while the Speedmaster adds an amagnetic “dust cover” between its movement and case back.

A note on strap materials and design:

The purpose of a strap is to hold the instrument securely and comfortably in place on the selected limb or other point of attachment. The importance of ergonomics (in terms of physical comfort) cannot be overstated, as an uncomfortable instrument finds itself unused and is therefore useless.

The metal strap, or bracelet, offers the lowest maintenance over time, and in some climates is the only realistic option, but due to its complex construction it is also the least reliable. Every pin that articulates the metal “links” or scales is a point of possible failure that can result in the damage or loss of the wristwatch.

The most secure strap variants yet known are based upon a one-piece design. By looping through the spring or fixed bars, the watch is secured even in the even of a bar failure. Typically constructed of nylon webbing, they are secured by either
Velcro or a conventional tang buckle (NATO straps).

In conclusion: The common factors in the above designs is that they were all built to fulfill the needs of their respective users; as any tool must be adequate to the task at hand and suit the hand that uses it. What beauty they have as timepieces exists in the purity of their designs, and in their aura of purpose. It is this purpose that gives them meaning and an authenticity that other watches merely strive for.

Of further interest in the history and development of instrument watches is Michael Friedburg’s series of articles in Past Time. Covering both the origin of instrument watches and modern adaptations of instrument watch design.

Photo Credits:

Study of Proportionsby Leonardo Da Vinci, scan by Mark Harden

IWC Mark XI by Greg Lorenzo.

Rolex Submariner by James M. Dowling.

Rolex GMT Master from Collecting Rolex Wristwatches by Osvaldo Patrizzi, courtesy of The Rolex Club.

Omega Speedmaster by Bo Hansen.

Breitling Navitimer by Les Zetlein.

Used with Permission.

Copyright © 2000 Carlos A. Perez

All Rights Reserved