Home/Field Notes/Stamp Identification and Dating: The Complete Guide

Identification is the whole job. Value, rarity, and authenticity are all downstream of knowing exactly what an object is, and almost every expensive mistake in philately traces back to skipping that step — reading a seller's title, matching a picture in a catalog by eye, and never measuring anything.

This guide is a method. It works on a US classic, a German inflation issue, a British Machin, and a stamp from a country you have never heard of, because it relies on physical evidence that exists independently of what anyone claims about the object. Follow it in order and you will identify most stamps correctly, and — more usefully — you will know when you have hit the limit of what you can determine yourself.

Work in a fixed order

The order matters more than any single technique. Identification done out of order lets a hypothesis form early and then quietly steers every subsequent observation toward confirming it. Recording observations before consulting a reference removes that.

Reading the inscription before anything else

A surprising share of identification failures are country failures. Many stamps do not carry a country name in a form an English speaker recognizes, and a good number carry a name that no longer corresponds to any current country.

Transcribe the inscription exactly, including diacritics and script. If the script is unfamiliar, transcribe the shapes as accurately as you can and use an inscription reference — most general catalogs include an index of inscriptions and abbreviations specifically because this problem is universal. Watch for currency units rather than country names: some issues identify their postal authority only by the denomination's currency, which narrows the field substantially.

Great Britain is the standing exception, and a useful one to know: as the originating postal authority it does not name itself on its stamps, and instead carries the monarch's portrait or silhouette. A stamp with a monarch's head and no country name is not a mystery, it is a British stamp.

Perforations

Perforation gauge is expressed as the number of perforation holes within a two-centimetre span, and it is measured with a physical gauge laid against the edge. Fractional gauges are normal and meaningful. A stamp may gauge differently horizontally and vertically, which is recorded as a compound gauge, and that difference alone can separate a common stamp from a scarce one.

Measure with the gauge, not by eye and not from a scan. Screen scaling makes on-screen measurement unreliable, and a scan at an unknown resolution is worthless for this purpose. If you are working from a seller's images, treat any perforation claim as unverified.

Watermarks

A watermark is a thinner area of the paper created during manufacture, and it is one of the strongest identification signals available because it is inherent to the sheet rather than added to the stamp. Watermarks are checked by laying the stamp face down in a black tray and applying a watermark fluid, which briefly makes the thin areas visible, or with a light box or specialized detector for stamps that must not be immersed.

Record the letterform, the orientation, and whether the design is single-line, double-line, multiple, or a repeating device. Orientation matters: a watermark that appears sideways, inverted, or reversed relative to normal is itself a catalogued variety in many countries.

Paper

Paper is chronically under-examined and frequently decisive. Within a single design family you may encounter hard and soft papers, wove and laid papers, chalky-surfaced papers, coloured and tinted papers, granite paper with visible coloured fibres, and papers carrying security threads or printed safety devices.

• Laid paper shows parallel lines when held to transmitted light; wove shows an even texture without them
• Chalky-surfaced paper has a coating that a silver test strip will mark; it also reacts badly to fluid and to soaking
• Granite paper contains short coloured fibres embedded in the sheet, visible under magnification
• Thickness and opacity distinguish printings in many countries and are best judged by direct comparison against a known example rather than in isolation
• Fluorescence and tagging under ultraviolet light separates many modern issues, including phosphor bands applied for automated mail sorting

Printing method

How a stamp was printed is usually determinable in a few seconds under magnification and angled light, and it separates issues that are otherwise indistinguishable.

Press type is a related question. Where the same design was produced on both flat-bed and rotary presses, the rotary version is stretched slightly in the direction the paper travelled, making the printed design measurably larger in one dimension. Measure the design itself, not the perforated stamp, since perforation placement varies.

Dating without a postmark

Not every stamp carries a date, and the date it does carry may be the date of an event rather than the date of issue. Several independent lines of evidence bound a date range.

• The postal authority itself — a country name, colonial administration, or currency that existed only within a known period
• The head of state depicted — a monarch's portrait, and often a specific portrait used only within a defined span
• Currency reform — denominations expressed in a unit that was introduced or abolished on a known date
• Printing technology — a method that was not available before or was no longer used after a given period
• Watermark and paper changes — postal authorities changed paper suppliers and watermark devices on documented dates
• Perforation policy — the introduction of perforation, or a change of gauge, is dated in every major catalog
• The cancellation — when present and genuine, a dated postmark gives a latest-possible-use date, which bounds the issue date from above

On cover, the postal markings are usually more informative than the stamp. Rate, route, transit marks, and destination backstamps together frequently fix a date and a service far more precisely than the adhesive alone can.

The back of the stamp

Roughly half the available evidence is on the reverse, and it is the half sellers are least likely to photograph.

• Gum — original, disturbed, regummed, or absent; the state and its evenness both carry information
• Hinge evidence — remnants, thinned patches where a hinge was removed, and the pattern of multiple hinges over time
• Thins — visible as bright patches against transmitted light and as dull flat areas under raking light
• Repairs — filled thins, closed tears, and rebuilt corners, generally showing as an area of different texture or fluorescence
• Embossing or grill — an intentional security device on some nineteenth-century issues, and a primary identifier where present
• Expert marks — small handstamps applied by expertizing bodies or historic experts; these should be photographed and never removed
• Pencil notations — previous owners' catalog numbers, which are a starting hypothesis and not an authority

Where identification stops and expertization begins

A careful collector working methodically can identify the large majority of stamps correctly. There is a defined boundary past which self-identification is not sufficient, and recognizing that boundary is itself a skill.

Submit to a recognized expertizing body when the identification depends on a distinction that is commonly forged, when the value gap between adjacent varieties is large, when the stamp is a known error, when an overprint or surcharge is involved on a valuable issue, or when you intend to resell at a level where buyers will expect a certificate. Confirm that any certificate presented to you is current, that the photographs match the item in hand including its faults, and that the issuing body is one the market recognizes.

Recording what you find

Identification that is not recorded has to be redone. A minimal record per stamp — the transcribed inscription, gauge in both directions, watermark, paper, printing method, dimensions where relevant, gum state, faults, and the resulting catalog identity — takes a couple of minutes and permanently converts an unknown object into a known one.

Photograph front and back at consistent lighting and resolution, name the files systematically, and keep the record alongside the images rather than in your memory. For a collection of any size this is also the basis of an insurance inventory, and it is far easier to build incrementally than to reconstruct after the fact.

The habit that matters most is the smallest one: write down the measurement before you look it up. Everything else in this guide is downstream of that.

Common questions