Pottery marks identification: a working guide to backstamps, numbers and dates

A pottery mark is whatever the factory, the workshop or the decorator left on the underside of a piece: a printed backstamp, letters pressed into the clay before firing, a painted number, sometimes all three at once. Identifying it means reading each element separately and then seeing whether they agree with each other.

Held to what it actually is, a mark is good evidence for three things:

• Who made it, or at least who sold it. Some marks name a factory, some name a retailer, some name an importer, and telling those apart is half the work.
• Roughly when. Factories changed their marks, and the wording, the crown, the added word, the added country all move in steps you can date approximately.
• Where. A country name, a language, a registration format, an importer's stamp.

A mark is poor evidence, on its own, for the things people most want from it:

• It is not proof of authenticity. A mark is the easiest part of an object to copy, because it is small, flat and printed.
• It is not a value. Two plates with the identical backstamp can sit at opposite ends of a price range depending on pattern, condition, rarity and who wants them this year. Identification and valuation are separate jobs, and anyone who runs them together is selling you something.
• It is not always unique. Factory groups, successor companies and licensed decorators shared and inherited marks, so one stamp can legitimately point at several workshops.

So the useful goal is not a verdict. It is a short, honest statement: this looks like this maker, made around this period, probably in this country, and here is how confident that reading is.

Turn a piece over and you are usually looking at a small crowd of marks, not one. They were put there by different people for different reasons, and treating them as a single blob is the most common way to go wrong.

Printed marks, the backstamp

The transfer-printed or stamped device that names the maker, often with a pattern name, a crown, a globe, a lion, a shield. This is the mark most people mean when they say pottery mark. Its wording is the richest dating clue on the object, because factories revised it whenever the business changed.

Impressed marks

Letters, a name or a shape pressed into the soft clay before firing. Because they are part of the body rather than sitting on top of the glaze, they are harder to fake convincingly and often older than the printed mark beside them. They can be very faint, and they usually only appear under raking light.

Incised and painted marks

Incised marks are scratched into the clay, often by hand, and are common on studio and art pottery. Painted marks, usually in a dark pigment under the glaze or a coloured one over it, tend to be decorator numbers, pattern references or the initials of a person rather than a company.

Registry and registration marks

British pieces often carry a diamond-shaped device or the letters Rd or Rd No. followed by a number. These record the registration of a design rather than the maker, and they are one of the tighter dating clues available, because they were issued in sequence. The diamond form is the earlier one and the number form the later.

Retailer, importer and country marks

A shop name is not a maker. Department stores and china retailers had their own marks applied to stock made by someone else, and importers added country-of-origin wording to satisfy the customs rules of the market they were shipping into. Collectors use the presence of a country name, and then the words Made in, as a rough staircase of dates: no country tends to read earlier, a bare country name later, and Made in later still.

Paper labels

Useful when they survive, weak when they do not, and trivially transferable between objects. A paper label on its own supports a reading, it does not establish one.

This is the question that stalls most people, because the numbers are the part no reference index can look up for you without context. There are only a handful of things a number on a base is likely to be.

• Pattern number. Usually printed or painted, often three to five digits, sometimes with a prefix letter or a fraction-like slash. It identifies the decoration, not the shape and not the date. Two pieces with the same pattern number and different forms are a matched set, not the same object.
• Shape or mould number. Often impressed, because it belonged to the making stage rather than the decorating stage. It identifies the form, so a jug and a bowl from the same range will carry different mould numbers and possibly the same pattern number.
• Size code. A single digit or a letter, frequently next to the mould number, distinguishing a range of sizes cast from the same design.
• Date code. Some factories stamped a coded year, as a dot system, a letter, a small pair of digits or a symbol tucked beside the backstamp. These are factory specific, which is why the maker has to be settled before the date code can be read.
• Registration number. Comes with Rd or Rd No. wording in Britain, or an equivalent phrase elsewhere, and dates the design registration rather than the individual piece. A piece can be made years after the design was registered, so this gives you an earliest plausible date and nothing more.
• Painter, gilder or tally marks. Small hand-painted numerals, initials or symbols applied by the person who decorated the piece, sometimes used for piecework counting. They rarely help with dating and often confuse an otherwise clean reading.

The practical rule: impressed numbers usually belong to the clay and the form, printed numbers usually belong to the pattern, and hand-painted numbers usually belong to a person. Sort them into those three buckets before you go looking anything up, because searching a decorator's tally as if it were a pattern number is how an hour disappears.

Marks get copied. They always have, and not always with intent to deceive. A workshop admiring another factory's output might borrow its device as a tribute, a later company might inherit a predecessor's mark legitimately, and a twentieth century reproduction might carry an eighteenth century crossed-swords device because the buyer expected one.

What you can look at without a laboratory:

• Agreement. Does the mark's period match the body, the glaze, the weight, the foot ring finish and the wear? Disagreement is the signal. A mark claiming an era the object does not support is worth more attention than the mark itself.
• Sharpness in the wrong place. Underglaze printing softens slightly under the glaze. A mark that sits visibly on top of the glaze, or that has the flat even edge of modern printing, is telling you something about how it was applied.
• Wear where wear belongs. A base that has stood on tables for a century usually has scuffing on the contact ring, and the mark inside that ring often shows some of it. Uniform pristine printing on a scuffed base is a question, not an accusation.
• Too much information. Marks that helpfully spell out a date, a maker and a claim to antiquity all at once are a modern habit. Older factory marks tend to be terse.
• The mark that is slightly wrong. A copied device is frequently a little off in proportion, in the spacing of the letters, or in a small detail of the emblem. This is the hardest test to apply from memory and the one where a reference image beside the piece earns its keep.

None of these is conclusive by itself. Stack three of them and you have a reasonable doubt, which is exactly the point at which the object deserves a person rather than another hour of searching.

Plenty of genuinely old pottery is unmarked. Marking became a widespread commercial habit rather than a universal one, and everyday wares, country potteries, redware and a great deal of studio work went out into the world with nothing on the base. An unmarked piece is not automatically a reproduction and not automatically worthless.

With no mark, identification moves to the object:

• The body. Earthenware is opaque and relatively porous where it is unglazed. Stoneware is denser and rings differently. Porcelain is usually translucent at the rim when you hold a light behind it. That single test narrows the field considerably.
• The foot ring. How it was finished, whether it was wiped, ground, glazed or left raw, and whether it carries stilt marks or kiln scars from how the piece was supported in firing.
• The forming method. Throwing rings inside a hollow form, a seam from a two-part mould, the softness or crispness of cast detail.
• The decoration. Hand painting shows variation in pressure and overlap. Transfer printing shows repeats and sometimes visible joins where the paper was wrapped around a curve.
• Crazing and staining. A crazed glaze with dirt settled into the lines is an age indicator, though it can be induced, so treat it as supporting evidence rather than proof.

Silver is a different discipline entirely, because British silver carries a legally required hallmark system that encodes assay office, standard and year in a way pottery marks never do. If that is what you are holding, our page on reading a silver hallmark from your phone covers that system rather than this one.

At an estate sale you rarely have an hour. You have a few minutes, a queue behind you and a piece in your hand, and the question is not what is this exactly, it is is this worth more of my attention. That is a triage decision, and it has a different standard of proof than a catalogue entry.

A reasonable way to hold it:

• Confident reading, ordinary maker. You know roughly what it is and nothing about it is unusual. Decide on the piece, not the mark.
• Confident reading, unusual maker or period. Worth buying time over, and worth photographing properly before you commit to anything.
• Uncertain reading, cheap piece. The cost of being wrong is small. Buy it if you like it and research it at home, where the light is better.
• Uncertain reading, expensive piece. This is the case where an expert earns their fee. An appraiser looking at the object in person can resolve things a photograph never will, and the cost of that opinion should be weighed against the sum at risk, not against zero.

The honest limit of everything on this page, and of any photo-based tool including ours, is that it works from images and conventions. It can tell you what a mark most resembles. It cannot handle the piece, feel the body, tap the rim or take it to the light. Identifications made from a photograph, by a person or by software, are informed estimates, and they are not a basis on their own for a purchase or a sale. When the amount of money involved makes being wrong expensive, that is the signal to get a person with the object in front of them.

• Backstamp. The printed or stamped mark on the underside identifying maker, trade name or pattern.
• Impressed mark. A mark pressed into the clay before firing, part of the body rather than applied to it.
• Incised mark. A mark scratched into the clay, usually by hand, common on studio pottery.
• Underglaze and overglaze. Whether a mark was applied before or after the glaze went on. Underglaze marks sit under a glassy layer and soften slightly, overglaze marks sit on the surface and can wear away.
• Registry mark. A British device recording that a design was registered, in either a diamond form or an Rd number form.
• Pattern number. A reference to the decoration scheme, not to the shape or the date.
• Mould or shape number. A reference to the form the piece was cast or pressed from.
• Crazing. The fine network of cracks in a glaze, caused by the glaze and body ageing at different rates.
• Foot ring. The raised rim a piece stands on, whose finish and wear carry a lot of quiet information.
• Marriage. An object assembled from parts of more than one piece, for example a lid from one and a body from another, which can produce two marks that disagree honestly.