Most old postcards arrive with the same question attached: when was it made? A handwritten date helps, but plenty of cards were never posted, and others carry a message written years after the picture was printed. The good news is that postcards leave a trail of clues, and once you know what to look for, you can usually narrow a card down to a decade or even a few years.

The checklist below works from the most reliable evidence to the least. Start with the printed details, then use handwriting and condition to refine your estimate.

1. Read the back before the front

Turn the card over first. The layout of the back is one of the strongest dating tools available, and it tells you a great deal before you look at the picture at all.

Early postcards had a plain undivided back: the whole surface was reserved for the address, and any message had to be squeezed onto the front. From around 1902, British and other postal authorities began permitting a divided back, with the address on the right and a message space on the left. A divided back therefore places a card after that change, though cards with undivided backs were still sold and used for a while afterwards.

Look also at the printed words. Lines such as "Post Card" or "Postcard" in different typefaces, the presence of a stamp box, and instructions about where to put the stamp all changed over time and act as rough markers.

2. Use the stamp as a date bracket

Stamps are useful but often misunderstood. The stamp gives you the earliest plausible date of posting, not the date the card was printed. A card printed in 1910 may carry a 1950s stamp because someone found it in a drawer and sent it decades later.

What stamps do give you is a range. A British stamp showing a monarch, or a printed value in pre-decimal currency, tells you the card was posted before the currency changed in 1971. Colours and designs changed regularly, and specialist catalogues list issue dates. If the stamp is still attached and untampered with, treat it as a solid bracket around the posting date.

3. Decode the postmark

The postmark is usually the single most precise clue on a posted card. A clear circular or squared mark often includes a town, a date and sometimes a time. Even a partial strike gives you the year.

When reading a postmark, note that dates were often written with the day first, then the month, then the year. A mark reading "12 8 14" is likely 12 August 1914, not 8 December. Look at the style of the mark too: machine marks, slogans and wavy lines replaced many handstamps over the twentieth century, and the format of the year changed from two digits to four at different times.

Reading a postmark step by step

1. Pick the clearest strike. There may be several. Work with the most legible one.
2. Find the year first. It is usually at the end of the date line or in a separate box.
3. Identify the town. Place names help confirm the card's origin and sometimes the publisher's location.
4. Check for a slogan. Advertising slogans, such as campaign messages or event promotions, can be dated from their design.
5. Note anything odd. A postmark from a different town to the publisher is normal; people post cards while travelling.

4. Study publisher names and codes

Postcard publishers dominated the market in the early twentieth century, and their markings are a goldmine. Names printed along the edge, often in small type, identify the firm. Many of these companies operated within fairly narrow periods, and their output changed style as printing methods developed.

Look for sequence numbers and reference codes near the publisher's name. These were not consistent across the industry, so they are more useful for spotting a series than for pinpointing a year on their own. However, if you can find a numbered series where one card carries a dated postmark, you can often apply that date to other cards in the same run.

5. Identify the printing method

Printing technology moved quickly, and each method leaves visible traces.

• Lithography: common in the earliest mass-produced cards, with soft, painterly colour.
• Collotype and photogravure: fine photographic detail, popular from the early 1900s.
• Real photographic cards: actual photographs printed on postcard stock, often with a glossy or matte finish and a hand-written negative number.
• Colour halftone printing: tiny visible dots under magnification, increasingly standard as the century progressed.
• Linen-textured and chrome cards: textured surfaces and high-colour gloss appear in later decades.

Printing style narrows the field but rarely dates a card precisely on its own. Combine it with the back layout and any publisher details.

6. Judge the image itself

The picture can support your estimate or complicate it. Vehicles, shopfronts, street lighting, uniforms and advertising signage all change on recognisable schedules. A street scene with horse-drawn traffic suggests an earlier date than one full of 1930s cars, though old photographs were sometimes reprinted for years afterwards.

Be cautious with famous landmarks. Publishers reprinted popular views repeatedly, and a card showing a well-known building may be much later than the scene's original photograph. Captions written in a particular typeface, or the addition of a "printed in" line, can help you separate an original from a reprint.

7. Weigh handwriting, wear and annotations

Handwriting is charming but unreliable. Styles of script changed, and people of all ages wrote in older conventions. Pencil notes, dealer prices and collection marks were often added long after manufacture, so treat them as extra information rather than evidence.

Wear tells a gentler story. Cards that were posted and kept in albums often survive in better condition than those carried loose in pockets. Foxing, fading, corner creases and discoloured edges all suggest age, but they reflect storage conditions as much as years. A clean card is not automatically modern, and a tatty one is not automatically early.

A quick ten-point checklist

1. Note whether the back is undivided or divided.
2. Look for a stamp box and its position.
3. Read any attached stamp and note its design and currency.
4. Decode the postmark: date, town and mark type.
5. Find the publisher's name and any code or series number.
6. Identify the printing method.
7. Examine the image for datable detail.
8. Check the caption typeface and any "printed in" line.
9. Assess handwriting, pencil marks and annotations separately.
10. Compare condition and materials against your estimated date.

Bringing it together

No single clue dates a postcard. The skill lies in layering them: a divided back, a stamp in pre-decimal currency, a postmark from the 1920s and a publisher whose output you recognise will together give you a confident estimate. Where the clues conflict, trust the printed evidence over the picture, and the postmark over everything else.

Record what you find as you go, even if it seems minor. A note of the publisher, the printing method and the postmark date turns a loose card into a documented one, and makes dating the next card in the same series far quicker.

Photo: Hermann / Pixabay