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Specialist terminology

Expertising and expertising termsold expertisingoverprints and surchargesprepayment in cashcommercial usagespecial types of issue or printingsouvenir sheetscoverpiecedouble print and blurred printpaperprinting processescancellationsstate of preservationfirst day sheetforgeriescolourFDCsheet positiontypes of frankingpostal stationerycataloguing of postage stamps: main types, sub-types, varietiesstorage and age-related changeswastebookletsmaximum cardspatternsreprintscoin-covers/sheetsphilatelic itemspostage stampsproofs, trials, essays, etc.offset printscollectors’ and dealers’ coversspecimenstypes of separationunused postage stamps

Specialised philatelic termshave been used since the end of 19th century. They have in the meantime often been revised and extended, most recently in 1993 jointly by the APHV, BDB, BDPh and BPP. They serve as the basis for the activities of BPP experts.

Published for the first time on the Internet on 10 July 2003 by a commission, in which in addition to four members of the BPP (Messrs.Geigle, Dr Oechsner, Dr Penning, Straub) a representative of the Michel Editorial Department (Mr Stenzke) and of the BDPh (Mr Maassen) took part, philatelic definitions for collectors and professional philatelists were prepared to use as guidelines for the determination and detailed classification of philatelic – and thus also expertisable – material. The AGM of the BPP authorised the Board of Directors on 24 May 2003 to set up a commission composed of members of the BPP to continue to extend and attend to the philatelic definitions, to adapt these to the latest state of research and to continue to publish these on the Internet. The Board has free rein in the makeup of the commission and any alterations.

Expertising and expertising terms

In the use of philatelic terminology, the expertisers of the BPP give their informed opinion on an examined item based on proven and binding terms and conditions, in accordance with the expertising procedures of the BPP, as to the genuineness and state of preservation (indication of quality) and will undertake to sign a certificate with personal liability according to the expertising procedures of the BPP and with regard to the civil law of the German Federal Republic.

In general parlance the terms “expertising” and “signing” will be used alike.
However,in the practice of expertising a distinction is made between the process of examining (“expertising”) and the documentation of the result (“signing”, “certifying”).

The items subject to examination are all those which are concerned with philately and postal history in the strict sense.

old expertising

This term is used for an expertisation, documented by signing, brief findings, findings or a certificate, for which no liability will normally exist.

Overprints and surcharges

These terms were formerly defined as follows:

Overprint: a change to an existing postage stamp by means of additional letters, words or characters, applied by hand or machine (changing the form of government, currency changes, changes in the purpose of usage etc.).

Surcharge: a change in the face value (also repeatedly) done by hand or machine.

Nowadays these terms are used on an equal footing with each other, and preference is given to the term “overprint”.

prepayment in cash: see under “franking”

Commercial usage

Commercial usage normally applies to a cover that was carried through the postal system, has an indication of the sender and addressee, is correctly franked according to the postal service used and has fulfilled a need for communication or has carried out some other purpose.

Philatelic items and collectors’ and dealers’ letters (qq.v.) are to be distinguished from such commercially used itemsas they lack one or more of the characteristics mentioned above.

Special types of issue or printing

Special issues and printings are produced for publicity, as specimens or for presentation purposes and are usually not postally valid. There are ministers’sheets, special printings of the final version (possibly also in sheet form) in equal or superior quality, sample cards etc.

Certificatesor findings will be issued for them.

Changes in format are often due to production methods and are subject to special consideration when expertised.

Souvenir sheets

The distinction between souvenir sheets and miniature sheets is made differently in the various catalogues. In Germany the distinction between souvenir sheets and miniature sheets is normally made according to the way it is done in the Michel catalogue.

Manufacturing-related variations in format occur with souvenir sheets and are subject to separate consideration when being expertised.

When ungummed or partly gummed souvenir sheets have been attached to a cover by using other types of adhesive, these blocks are regarded as being in fine condition insofar as this external adhesive has caused no obvious defects (such as external adhesive stains, discoloration, wrinkling due to the adhesive etc.)


In common parlance, a cover is a written communication to a designated recipient, either folded (a folded letter) or in an envelope.

The term “cover” is used here in the philatelic sense, that is usually an actual collector’s item bearing a franking, also postal markings and endorsements.


Pieces are portions cut from entires. In regard to expertising, this term is also used for collectors’ and dealers’ letters that are not franked according to postage rates (e.g. covers with complete sets or similar) and also philatelic items.

Double print and blurred print

A double print exists when two clearly separateimpressions can be seen on the front of a postage stamp. Double prints are certified and marked accordingly.

In the case of a partialdouble print, at first a sheet was only partly printed by the machine, and then it was completelyprinted in a second “pass”. The more difficult it is to recognise a double print, the more likely it is to be sold over the counter. Clear, striking double prints are usually noticed during quality control and are removed. If a doubly printed image is not clearly detectable, as both images are too close together, a double print may still exist, though due to lack of evidence only a blurred print may be assumed.

A double image is nota double print, but a phenomenon that occurs only with offset printing. It is not caused by a double insertion of the sheet, but a double application of the print image to the printing blanket cylinder, if the machine had briefly had been kept running, for example, for the removal of a damaged sheet. Double images are printing oddities.

Blurred prints (shadow prints) due to a squeezing-out of the ink as a result of insufficient care in printing (uneven surfaces) also exclusively occur in the direction in which the sheet passes through the printing machine. Here the printed image has a more or less prominent shadow; it doesnot occur a second time. Blurred prints are classified as printing oddities and are not signed or certified.


In the 19th century, the paper used for printing stamps was mostly produced by hand. The use of papermaking machines, firstly of the circular screening type, began in c. 1800, andlater continuous screening machines were used.

Paper components

a) fibrous materials
b) finishing materials

The most important fibres for papermaking are of vegetable origin. They are extracted from cotton, bast and other fibres, wood pulp and cellulose pulp. Among animal fibres, only wool has a certain relevance. Fibres made from recycled paper play a major role.

The treatment of fibrous materials is done by crushing (cutting, tearing, pounding, grinding). This is followed by a cleansing wash (cleaning, degreasing), ink removal (for example with recycled paper), bleaching, heating (in the case of chemical digestion of cellulose).

Fillers, binders, glue-like sizing agents and dyes are used as finishing materials:
Silicates (kaolin, talc) are used to improve the surface quality and the degree of whiteness; sulphates (barite, gypsum, alum), carbonates (chalk) and oxides (titanium dioxide) are used as finely ground fillers.

They account for up to 30% of the weight and fill the cavities that occur due to the entanglement of fibres.

The application of a sizing agent serves to increase strength and to improve printability. Animal sizing agents are extracted from bones, hides and skins or casein; vegetable sizes play a minor role in comparison with the synthetic glues used at the present time.

Natural starch is used as a binder.

Dyes may be added to the liquid paper pulp or subsequently applied to the surface. Paper inherently has a slight tint of yellow, and so red or blue dye is added in small quantities to compensate for this appearance. This is referred to as the “brightening” of the paper. A white appearance is created by the additive colour mixing. Optical brighteners are used which convert short-wave radiation in the ultraviolet range into visible light.


Fibres and finishing materials are thoroughly mixed with plenty of water in large vats (the so-called Hollanders), equipped with rotating blades. The resultant material passes on to the screen of a machine which moves continuously and performs lateral shaking movements. As a result, the fibres of the paper become aligned mostly in the direction of the forward movement of the screen.The water runs through a sieve of the papermaking machine and in addition it is removed via suction chests and, where appropriate, the watermark is impressed in the soft pulp by passing it over a screen roller (dandy roll). The result is an actual watermark such as is normally found on postage stamps.After the couching roll, which eliminates more water mainly from the surface of the “web”, the paper passes on to an endless felt conveyor into the drying section. Theremaining water now evaporates over heated metal cylinders. After separation from the felt conveyor, the first smoothing and consolidation of the paper occurs between calenders. Then it will be cut by a rotary machine into the required width.

Wood-free and wood-containing papers are distinguishable according to the material used. The latter include a greater or lesser proportion of wood pulp. These papers mostly have a rough surface of coarse texture. The more wood pulp they contain, the greater are the defects in quality, such as holes occurring in the paper. Due to their lignin content from the wood pulp used, these papers tend to be susceptible to mildew and yellowing. However, wood-free papers are much smoother, whiter and more resistant to ageing.

Treating the paper

Firstly, the broad rollers are divided into narrower ones. Their width depends on the size of paper required for printing. If there are remainders which are at least as wide as the required length of the sheet, these will be cut into a narrower roll from which individual sheets are latermade at the original sheet width. From this process there results paper with the watermark turned through 90 degrees (upright or sideways watermark). To achieve a still better surface, the paper can be treated with single-sided or double-sided surface sizing. The best possible degree of whiteness, but also best smoothness is achieved by single-sided or (not required for stamps) double-sided pigmentation, mainly with chalk. Double-sided pigmented paper is termed art paper, and single-sided pigmented paper is “chromo” paper (in philately, chalk-surfaced paper).Both untreated and sized or pigmented paper can achieve a smoother surface by passing again, or several times, through a smoothing (satin finish) calender.
Afterwards the gum for the stamps is applied to the back of the paper. The paper is now ready for rotary printing; for sheet-fed printing the so-called cross-cutters are used to cut the paper into the correct sheet length (or width). Several rolls may bedealt with at the same time and a corresponding number of lengths stacked cut and stored. It follows that successive sheets in a stack need not necessarily come from the same roll. Finally, the paper is counted and packed.

The influence that the paper has on the finished stamp

Variations in the content on leaving the “hollanders”, variations in the bulk content at this same stage and differences in the satinising may lead to slight differences in the thickness of the paperin the same manufacturing batch. Differences in the composition of the paper (the proportions of different fibres, the type and particle size of the finishing materials) also lead to slight differences, also in the coloration of the paper. This is all the more significant when several different paper mills are involved in the production, because in this case just the necessarily different water quality may lead to differences in the product.

Over longer periods of time paper may also be affected by ageing and environmental factors. This is due mainly to the chemical properties of the paper, because in spite of all diligence a chemically neutral product cannot be expected. Due to its hygroscopic properties, paper “breathes” almost constantly the surrounding air, with all its components such as humidity, various gases and also acidic compounds. Of course the paper dries out again when environmental conditions change; only the most “inhaled” chemicals will remain in the long term and will lead to discoloration of the paper (browning, yellowing). If paper is exposed to light over long periods it can also turn yellow or brown. There are also otherreactions concerned with components of the ink and the gum. As a result of all of these influences, the structure of the paper will be damaged in the long term.

Printing processes

The processes which have been used for printing stamps since their introduction have often changed and have constantly been evolving. This cannot be dealt with in detail here. There have been many differences between the specialist terminology used by printers and the philatelic terminology that has been used over decades, and in philatelic circles inaccuracies have sometimes crept in. Both types of phraseology are therefore given.

The characteristics of the printing equipment and paper are used to describe the printing process. The following are essential

a) the type of image transfer (direct or indirect),
b) the geometry of the type of printing and the Druckkörper
c) the fine structure of the type of printing and
d) the type of paper (roll or sheets).

The characteristics of the printing equipment and paper are used to describe the printing process. The following are essential

a) the type of image transfer (direct or indirect),
b) the geometry of the printing plate and the printing cylinder or base
c) the fineness of the printing plate
d) the type of paper (sheets or rolls).

Classification of printing processes according to the fine structure of the printing plate

Printing processes are traditionally classified, according to the type of printing plates, into four main types:

a) Surface printing: the printed areas of the plate are higher than the non-printed areas. Example: typography.

b) Planography: the printed and non-printed areas lie almost in the same plane. Examples: offset printing, lithographic printing.

c) Line-engraved printing: the printed areas of the plate are engraved into it. Examples: photogravure, intaglio.

d) Screen printing: the printing plate is a template with an image that allows ink to pass through, while non-printed areas are impermeable (rarely used for printing stamps).

The so-called embossing (relief printing) is not an actual form of printing, but is used in combination with surface printing and planography to emboss the paper. Other layers may be applied in addition to the deformation of the paper – or without this – such as for example metal foils.

Printing principles

A certain amount of pressure is necessary for the transfer of an image from the printing plate to the paper; this is applied to the printing plate by a pressure cylinder or base.

a) direct printing: the printing plate is pressed directly on to the substrate (usually paper). The design to be printed is a mirror-image on the plate; on the paper it is the right way round.
b) Indirect printing: the image is printed indirectly from the printing plate via a transfer cylinder (rubber blanket cylinder) on to the paper. The image on the printing plate is the right way round; it is a mirror-image on the transfer cylinder and the right way round on the paper.

Regardless of the printing process, there are several principles, which are determined by the geometry of the printing plate and the printing base:

a) Flat to flat: the printing plate and the printing base are both flat.
b) Flat to circular: the printing plate is flat; the printing base is a cylinder.
c1) Circular to circular (direct): the printing plate and the printing base are both cylinders.
c2) Circular to circular (indirect): the paper is printed indirectly via a transfer cylinder.

Distinction is made according to the type of paper (sheets or rolls); there are three types of printing:

a) Sheet printing with flat-plate machines (philatelic description flat-plate printing)
b) Sheet printing with cylinder machines (e.g. offset printing)
c) Roll printing with cylinder machines (roller or rotary printing).

The products of roller printing are prepared for three types of usage – counter sheets, stamp coils and roller-web sheets.

The type of substrate

For printing postage stamps the paper (substrate) as the basic material is either cut into individual sheets (typographical designation “sheet fed printing”) or comes from a roll (typographical designation “cylinder”). The shape of the final product (sheet or roll) is referred to in philately – sometimes incorrectly – as sheet-fed or web-fed printing.

Explanations of the main procedures of in printing technology

Typography: ink is transferred from rollers on to the higher areas of the printing plate. The non-printed areas remain free of ink.

There are different kinds of typography which vary in their nature. The oldest kind of typography is letterpress printing, in which the printing plate is composed of movable type. Letterpress is a colloquial term for typography.

Modern typographic plates are made from synthetic photosensitive materials. The printing plate is no longer made up from sections, but forms a compact shape with text and image elements.

Letterset (indirect printing): the printing plate has raised areas for the image to be printed, and this is transferred to the paper via a printing blanket – as in offset printing. The blanket itself is not a printing plate.

Flat-bed printing: the printed and the non-printed areas are on the same level in flat-bed printing. The most commonly used flat printing process today is the offset process.

The “wet offset” process depends on the fact that water-based and oil-based substances do not mix. Aluminium sheets are predominantly used as printing plates, on which the areas to be printed consist of a thin layer of ink.

During the printing process, the printing plate in the machine is first barely moistened with water. The bare aluminium has a water-attracting (hydrophilic) capillary surface, while the emulsion repels water (hydrophobic), so that these places remain dry.

In the next stage the ink-covered cylinder is rolled against the printing plate transferring the (oily) ink only on to the dry and oil-friendly (oleophile) emulsion. The water on the bare aluminium repels the ink.

During the actual printing process the ink is transferred from the ink-carrying image areas first to a rubber cylinder and from this on to the paper (indirect printing process).

Offset printing has become one of the most commonly used printing methods, not least due to its excellent quality and the relatively simple and low-cost production of printing plates.

Intaglio: in this method of printing the image areas are lower than the non-printed areas.

With intaglio printing (or “line-engraved printing”) the areas to be printed are engraved, cut, pressed or etched into the surface of the printing plate. After inking the printing plate the ink is removed from the surface of the plate by paper or some form of textile, applied in the opposite direction to the turning of the cylinder, so that ink remains only in the crevices in the plate. From there, the ink is transferred to the paper during the printing process.

In rotogravure printing, the printed image consists of many tiny hollows. During the printing process, the printing plate is completely inked so that the hollows fill with ink. Then a “doctor” blade cleans this excess ink from the non-imaged areas, so that only the hollows are filled. The printed image is then transferred to the paper under high pressure.

With variable-depth rotogravure (traditional rotogravure), the plates for printing halftone images are etched at different depths, but are equal in size. So the doctor blade has a guide on the plate that does not extract the low-viscosity printing inks from the recessed printing elements; the entire printing plate is provided photo-technically with a network of grid strips.

With variable-surface rotogravure (autotypical gravure printing) the tonal values of the template are separated for the reproduction of half-tone images with different-sized dots, which are etched into the cylinders at almost the same depth. The fineness of the grid is called grid spacing.

Other printing processes

In more recent times, digital printing processes have played an increasing role:

Thermal printing, dot-matrix printing, inkjet printing, laser printing.

Traditional philatelic terms for printing

a) “Plate-printing”: printing on to individual sheets of paper with a flat printing plate (technical term “sheet-printing on a flatbed printing machine”).
b) “Rotary printing”: the printing is usually done from a cylindrical plate on to an unwinding roll of paper (technical term “rotary printing on rotary printing machine”).
c) “Roll-conveyor sheets”: continuous printing on to a roll of paper, actually intended for the production of coil stamps. (The preparation roll-sheets for sale at post office counters is not a particular kind of printing, but is an emergency measure with printing machines that lack a cross-cutting device, necessitating manual separation).

Printing on roll-conveyors is divided into:
Printing plates without value- and number-strips for the later preparation of coils of stamps, and in special cases roll-conveyor sheets, and
Printing plates with value- and number-strips, which are separated within the machine by means of a cross cutting device for preparing counter sheets.

The device used for printing is referred to as a “printing plate” even if it was a printing cylinder. As a result, the term “plate error” is imprecise, because errors due to the circular nature of the plate are thus described. The expression “cylinder error” would be correct in this case.

Because the production of printing plates has been the result of a great deal of technical development which still continues, the reasons for the occurrence of printing varieties are often fundamentally different. With photogravure there are for example the “chrome errors”, where new dots of ink appear as the chromium plating on the cylinder slowly dissolves and so new hollows form that attract the ink.

Philatelists understand the word “sheet” to mean a counter sheet, while the printer thinks of the printed sheet, which may include different numbers of counter sheets depending on the printing process.

As the traditional, often imprecise terms are rooted in philatelic usage, changes can only be made with difficulty, or very gradually.


Postage stamps were made unusable by the application of a postmark, less usually by handwritten cancellation with pen & ink etc., or by similar measures to prevent postal re-use (generally referred to as “postmarked” or “cancelled”).

Pen cancellation: a handwritten cancellation, for example with the date, place, initials, signature, pen-line, crossing-out etc.

Cancellation may be done by perforating with a metal punch. Perforations made by companies and authorities (such as the ‘POL’ perfins) are not a type of cancellation, but a security measure.

Stamps may be cancelled by the use of postmarking handstamps which are mostly made of metal, but may also be made of rubber, wood, linoleum or similar materials.

A cancellation is regarded as genuine if it basically consists of a postmark used by the postal service during the period of validity of the stamp (a “contemporary cancellation”).
It is completely irrelevant whether this took place within the framework of the normal postal service or for collecting purposes, as it is not usually possible to establish whether or not a postmark on a loose stamp or a piece of an envelope was actually used at the right time in the normal postal service.

Forged postmarks are either imitations of genuine postmarks or are fantasies. Cancellations may nowadays also be hand-drawn or applied photo-mechanically. Such creations are forgeries.

All cancellations that were applied by unauthorised third parties using genuine, but evidently back-dated postmarks (so-called “misuse”), also cancellations made using genuine postmarks outside their period of validity are regarded as forged.

Cancellations done for philatelic purposes

a) Postmarks printed on to postage stamps (such as counter sheets, miniature & souvenir-sheets) and philatelic products (such as first-day covers, first day sheets). Such cancellations made by typography are also known as cliché cancellations.
b) Mass cancellation done by hand on counter sheets with postmarks used specifically for this purpose.
c) Backdated postmarks used by authorised agencies for cancelling stamps for collectors. Previously, such cancellations were often incorrectly referred to as “cancelled by favour”.

Cancellations done in advance are applied to stamps for streamlining purposes, either by the postal authorities or with their permission, during the production of the stamps or afterwards, in any event before they are put on sale.

State of preservation

In general philatelic parlance the terms “never hinged”, “unused”, “used”, “on cover” and “on piece” are used to indicate the state of preservation.

In giving expert findings and certificates the “conservation status” is understood to indicate quality. This can be indicated as “flawless” or require a description of any faults.

The item under examination has no faults, taking into account the factors relating to the issue when assessing its conservation (for example with regard to separation, gum, centring, colour freshness; with entires also any signs of wear and ageing).


a) Obvious faults: damage such as such as separation damage (also re-perforation), gum faults, tears, surface rubs, stains, thin spots, etc.
b) Repairs, embellishments: repairs are carried out either by using foreign material (closing a tear, filling thins, adding margins, re-gumming etc.) or without adding external materials (removing dirt, mould or ink stains, ironing-out a crease). The latter is also called embellishment.

A forgery may also result from the manipulation of a different stamp or variety (by attaching a scarcer perforation or joining together portions of different stamps),

It is the task of the expertiser to establish the state of preservation of a stamp, but not to value it. Even a stamp in flawless condition may vary considerably in its value according to its attractiveness, the clarity of the postmark and many other characteristics. These may however not be represented by an expertising mark, they may only be addressed objectively through a description in findings or certificates.

First Day Sheet: see Philatelic items


Forgeries of stamps

Here we differentiate between:

a) Forgeries, when the whole stamp is completely forged.
b) Fakes, when changes have been made to the original postage stamp (such as by changing the gum structure, new gum, colour changes, trimming off the perforation teeth, adding a forged overprint, a forged or enhanced cancellation or other additions etc.) so as to give the appearance of a very rare postage stamp.

Forgeries of covers

Here we differentiate between:

a) Complete forgeries, when all components of the cover are forged.
b) Partial forgeries due to changes being made (adding, removing, or replacing components of the cover, such as the postage stamps, cancellations or additional markings, notes, address or sender information).

These are differentiated according to their purpose:

a) Forgeries intended to deceive the collector. In addition to the above complete or partial forgeries, these also include fantasy and deceptive stamps damaging to the postal service, being unauthorised issues from real or non-existent “countries”.
b) Forgeries intended to deceive the postal service, including forgeries produced for espionage.

Forgeries of expertising marks
Stamps and covers are also found with expertising marks. For this reason, higher-quality items are usually provided with tamper-proof certificates or reports.


The term “colour” may be discussed with differing emphasis from a scientific, printing, physiological or philatelic point of view.

Objective colour properties are determined using physical or chemical methods. These include:

a) the colour shade that is determined by the wavelength of the electromagnetic radiation emanating from coloured pigments,
b) the colour saturation, which indicates the degree of colour compared to an equally bright shade of grey,
c) the colour brightness, which compares the luminance with normal white.

Subjective colour properties are based on human sensations. They are triggered by electromagnetic radiation (light), conveyed by the eye and processed in the brain.

a) The sense of sight experiences colour as a subjective sentiment triggered by the objectively given colour stimulus.
b) The perception of colour is a mental process, which depends on, among other things, the nature and strength of the lighting, the environment, spatial relationships and the condition of the human visual apparatus.
c) Lighting: the colour of an object is comparable only with constant lighting! However, the eye is able to compensate to a certain extent for changes in the type of light and illumination. Thus, the assessment of a colour will also be subjectively affected.

Printing inks are coloured materials that consist of three main components:

a) Colorants (pigments)
b) Binding agents (varnishes and resins)
c) Auxiliary substances (solvents, solids).

The fundamental physical-optical properties of colourants are their absorption and spreading abilities.
Because the printing processes differ in the location of the printed areas, printing inks with specific properties must be used for each type of printing.

Chemically different colourants can – whether pure or in mixtures – on the one hand give the same colour perception, and on the other hand, chemically identical colouring matter can give visually very striking and different colour impressions owing to different mixing, pigment sizes, binders and solvents, drying materials and papers as well as uneven print finishing.

Printing inks on postage stamps are subject, in the longer term, to the same climatic and chemical influences as the paper. They may change colour by the reaction of a metal component with sulphur-containing substances, environmental influences, light-sensitive dyes that fade, reactions with the stamp’s gum or paper, as well as album material, etc. The age-related browning of varnish can also play a part.

Colour shade differences (catalogued sub-types that in philatelic usage are termed simply “colours”) are usually groups of colours that show significant differences in the same main colour (e.g. green: yellow-green, blue-green), which can, however, be separated visually (sometimes only under UV light).

Colour shade differences are usually due to different mixtures of ink.
They may, however, in some cases also be caused by chemical or physical (mechanical) effects during the printing of individual sheets or even within a sheet, such as the so-called colour variations due to variations in the saturation of a printing ink (light and dark colour perceptions). Such “transitional pieces” are sometimes not easy to classify.

Within the catalogued colour shade differences there are also a greater or lesser number of nuances, and usually the greatest number of these nuances are in the commonest range of colours.

When cataloguing colour shade differences, because during historical development no distinctions can be made regarding their formation, a particular stamp might have two catalogued colour shades which, although distinguishable visually, may not appear to be very different, while another stamp might have strikingly different shades which are not precisely separable.

Catalogued colour shade differences will be signed and certified.

Errors of colour are accidental or unauthorised printings of a stamp in a colour other than the one intended.
Catalogued errors of colour will be signed and certified.

Colour changes are intentional changes in the colour due to a new printing. The desired change may be to a colour in the same range of shades (e.g. dark green instead of green), or it may be to a different colour (e.g., red instead of green).
Usually, new “main” catalogue numbers are allocated to colour changes.

Discoloration is an incidental change in colour after the sale of stamps at post offices, such as by oxidation, sunlight or solvents, as well as intended or unintended chemical (biological) influences.
Significantly discoloured stamps are usually signed, or the signature/mark is placed higher. Certificates with the relevant information can be issued for high-quality items.

Storage- and age-related changes: discoloration invisible in normal light, particularly weak fluorescence, traces of optical brighteners or signs of photo corner storage, which can be seen only by technical means (such as UV light), are not regarded as faults.
Storage- and age-related changes such as patina, stains, fading or discoloration, which are visible in ordinary white light require different consideration. These changes are not necessarily regarded as faults.

Colour proofs: see Proofs under e) Proofs

Colour trials: see Proofs under b) Trials

FDC: see Philatelic items

Sheet position

The sheet position of a stamp is determined by the position of the upright stamp, independent of any marginal inscriptions. Stamps are counted from left to right in horizontal rows, unlike the postal numbering system from top to bottom.

Types of franking

Originally, the word “postage” almost always referred to the charge made for carrying a letter that was to be paid by the recipient. Prepayment made by the sender was referred to (in international usage) as “franco” or “free”. Prepayment by the sender became the normal rule with the introduction of the postage stamp. The word “franking” then became the norm in regard to describing the amount paid by the sender for the conveyance of a letter. The phrase “postage due” refers to a higher charge for conveyance that is collected from the recipient.
The word “franking” is therefore understood to mean the prepaid cost of postage; “correctly franked” refers to a letter prepaid with the correct amount of postage.

Single franking (EF) correctly prepaid: a postage stamp on a cover.
A correct single franking is when the full cost of postage for an item of mail or a chargeable postal service is paid by a postage stamp according to the tariff.

Multiple franking (MeF) correctly prepaid: several copies of the same stamp on a cover.
A correct multiple franking is when the full cost of postage for an item of mail or a chargeable postal service is paid by several identical postage stamps according to the tariff.
Multiple frankings may also, in the fundamental sense, be when the franking consists of different sub-types of the same stamp (e.g. the same stamps with different perforations).

Mixed franking (MiF) correctly prepaid:
Different postage stamps or different types of prepayment on a cover.
A correct mixed franking is when the full cost of postage for an item of mail or a chargeable postal service is paid by different postage stamps or different types of prepayment at the time of posting. The prepayment of part of the postage in cash is regarded as a mixed franking.

Colourful franking:
This is a sub-type of mixed franking within a particular issue of (often definitive) stamps. It is a franking consisting of stamps of different values or colours within a particular issue.

Payment in cash
If the postage for an item of mail or a chargeable postal service is paid without the use of postage stamps, either in cash at time of posting or officially deferred, this constitutes payment in cash.
Payment in cash may be required during emergencies and in times of war in the absence of postage stamps, and for example may be documented in the form of “fee paid” handstamps and/or handwritten notes on the item of mail.
Payment in cash also occurs as a form of postal automation for bulk postings (mainly printed matter or other kinds of reduced-rate mail items) by using “fee paid” postmarks or imprints (also from franking machines). Dated postmarks are usually not required here.
If payment is made in cash by the use of local “paid” labels that are not made available to the public, this is a form of payment in cash (e.g. German local issues).
If the postage on an item, or payment for a chargeable postal service is made partly in stamps and partly in cash, this is partial payment in cash.

Underfranked letters are those whose franking does not cover the full cost of postage. An amount (usually larger than the deficiency) is to be paid by the recipient – the “postage due”.
Underfranked covers are subject to different consideration for expertising and certification.

If postage stamps of a higher face value than that of the imprinted stamp are accepted, this is not a case of underfranking, but correct franking.

Overfranked: letters are those on which the value of the stamps exceeds the postage rate for conveying the letter (see also “Pieces” and “Collectors’ and dealers’ letters”).
A “forced excess franking” exists when the postage for an item of mail or payment for a postal service is not covered by the postage stamps attached.
Overfranked covers are subject to different consideration for expertising and certification.

If, due to a postage rate reduction, a postal administration officially permits the sale to the public of postal stationery, for example, at a lower price than that of the imprinted stamps, this is not a case of overfranking, if the selling price is in accordance with the tariff.

Correct franking / incorrect franking:
If the franking on a cover (type of franking and postage stamps) is done in such a way as was permitted or tolerated for the place and time of posting, this is a correct franking. If the franking or part of the franking consists of postage stamps that were not valid, no longer valid or not yet postally valid, it is an incorrect franking.
For this classification it is largely irrelevant whether the cover with the incorrect franking was forwarded without complaint or if the non-valid postage stamps were objected to.
Incorrect frankings are subject to different consideration for expertising and certification.

Postal stationery

Postal stationery comprises envelopes, cards and other items intended for use in the postal service with imprinted stamps or pre-applied handstamp impressions which must have been prepared prior to sale at post offices.

Postal stationery: see also ‘Postage stamps’

Used postal stationery: see also ‘Postal stationery’

Postal stationery (covers)

Postal stationery includes envelopes, cards, parcel and small packet cards, money transfers, etc. and official or government forms (also those of private origin) for use in postal communications with or without adhesive postage stamps.

Cataloguing of postage stamps: main types sub-types varieties

Main types, sub-types and varieties are distinguished in accordance with their descriptions in the “Kohl Briefmarken-Handbuch” and the “Neues Handbuch der Briefmarkenkunde”.

The main type is usually the form of a postage stamp that was intended by the issuer.

Sub-types emerge – intentionally or unintentionally – during the fulfilment of the print order. Sub-types can for example be variations in the colour shade, gumming, paper, watermark or perforation as well as design differences.
Varieties are, typically, unintended deviations from the intended production order and may often be striking and no longer covered by this. These include for example plate flaws, imperforate or partly perforated stamps, variations in the colour or the paper, the position of the watermark, overprint or surcharge, inverted design elements, partly or completely missing prints and such like. These varieties are often repeated in particular places on the sheets from a printing or part-printing.

Accidental misprints are not varieties. Printing errors occur merely by chance during production and are seen only on single sheets or small parts of the print run. They include for example blurred impressions, doctor blade flaws, spots, ink blots, colour shifts and misplaced overprints. Usually, printing errors are not listed in MICHEL catalogues. Their cataloguing, if necessary, is solely in specialised works.

Sub-types, varieties and printing errors whose status was not entirely clear have, over the course of decades, been shown in catalogues. This cataloguing is often maintained for historical reasons.

Storage and age-related changes

Storage- and age-related changes: discoloration invisible in normal light, particularly weak fluorescence, traces of optical brighteners or signs of photo corner storage, which can be seen only by technical means (such as UV light), are not regarded as faults.
Storage- and age-related changes such as patina, stains, fading or discolouration, which are visible in ordinary white light require different consideration. These changes are not necessarily regarded as faults.


Printer’s waste is unusable printed matter resulting from technical faults, and also from setting up the machine during the printing process. It includes all the material that has been made unusable for the actual postal purposes the stamp.
Waste is usually destroyed by the printer. If identifiable waste illegally comes on to the market, this is not marked or certified.


A stamp booklet is an assembly of postage stamps that are sold together, one or more pages having stamps of the same value or different values. Depending on the composition, stamp booklets may include interleaving which is designed to prevent stamps sticking together and can be used as an advertising medium. The booklet pages are attached to the stamp booklet cover by stapling, gluing or sewing. Self-adhesive stamps are applied directly to the backing sheet which serves as the booklet cover.
Booklets are generally printed in (se-tenant) sheets, the so-called stamp booklet sheets, from which the individual booklets are then assembled. There may be intermediate blank fields on these that are sometimes decorative or may contain advertising. The margins of stamp booklet sheets often contain ink bars, also printer’s notations which are normally trimmed off in the production of booklets but in rarer cases can still be found in the page-margins of stamp booklets.

Maximum cards

Maximum cards are – strictly speaking – picture postcards with a postage stamp affixed to the picture side, the design of which is also a reproduction of the same stamp, the stamp itself being cancelled with an appropriate special postmark, sometimes of an appropriate design. They are a kind of philatelic postal item.
Broader definitions allow similar, but not identical designs for the stamp and postmark on the maximum card. Depending on the provider, distinction is made between maximum cards of official and private origin.


A term used for a kind of specimen (q.v.), in the form of a depiction of the design of a postage stamp that is intended to be issued. These “patterns” were sent to the press and authorised recipients for information, usually before the date of issue.
Deutsche Post issued these “patterns” in the form of handstamps in of various shapes and forms until the end of 2002. They are never expertised.


Official reprints are only such prints as are prepared from the unmodified original print medium (printing stone plate, cliché, etc.), prepared by the same printing process as the original postage stamps after final adjustment of the printing, and usually after the expiry of the stamps’ validity. Reprints may also be produced in colours other than those of the originals.

Private reprints must be marked as such, otherwise they are forgeries.

Printings of stamps that were made after the expiry of the validity of the stamps, either by a different method of printing or by one that had been modified, and so were not used by the authorised issuer of the original stamps, are unofficial reprints.
Reprints that are privately produced, and are not marked as facsimiles, will be marked as forgeries

Reprints and unofficial reprints are marked as such when expertised.

coin-covers/sheets: see Philatelic products

Philatelic products

Philatelic products are products including stamps that are made by official or state bodies, or by the private sector, for collecting purposes. They include first day covers, first day sheets, maximum cards, coin-covers, commemorative and souvenir sheets, yearbooks, presentation packs and similar items.

FDC: This abbreviation stands for “First Day Cover”. It can be an ordinary cover (q.v.) or a philatelic product (q.v.). An FDC is franked with postage stamps that have been cancelled on the first day of issue with a dated or specially created first day postmark. Distinction is made between FDCs produced or authorised by the Post Office and privately produced FDCs.

ETB: This is an abbreviation of “Ersttagsblatt” or “First Day Sheet” and it is a philatelic product with postage stamps, a related first day cancellation and a description of the reason for issue and / or an illustration. A First Day Sheet is not intended to be delivered by post.

A coin cover is a philatelic first day or special commemorative envelope or sheet, to which a (special) coin or medal relating to the stamp issue is attached (in a transparent window). It is a type of philatelic product issued and sold by an official body (such as the Post Office) or by the private sector.

Postage stamps

Postage stamps are stamps issued by a body authorised to operate the postal service (a government agency, postal administration or licensed private company) or postage stamps and postal stationery manufactured and issued on their behalf, which serve

(a) as a receipt for a particular postal service (including internal Post Office usage), or
(b) as a confirmation of post-free status (e.g. post-free stamps, Field Post stamps), or
(c) as a condition of entitlement to postal conveyance (such as compulsory tax stamps, postage due stamps, Field Post entitlement stamps).

If postal authorities produce, or allow to be produced, stamps or postage fee labels under special conditions (local or emergency issues), these are regarded as postage stamps if the need for their use is proven or if the issue has been sanctioned by an authority regarded as having postal jurisdiction.

Postage stamps are stamps which are manufactured by stamp printers, meter marks (post- and sender’s meter marks, online postage stamps), as well as international reply coupons (IAS).

Private postage stamps may also be referred to as postage stamps, as long as they are issued by a State-licensed private postal facility. A specific prerequisite is national recognition and consent for the operation of a postal service, with acceptance, forwarding and delivery of postal items from and to anyone. This postal service may be regional or local.

Advisory labels that do not represent an authorisation for the acceptance or transporting of mail, and which purely provide information for the handling of mail items (e.g. registered, express, air mail, “receiver pays the fee ” etc. labels) are not postage stamps

Privately produced stamps that do not have an authorised postal licence are not postage stamps but vignettes.

Proofs,trials essays etc.

These products are the precursors of postage stamp production and are not postage stamps as they are not at all intended for postal use. They can vary in their format, and include:

a) Artist’s drawings for new postage stamps, which are usually larger than the issued stamps and are drawn by the designer or privately printed on behalf of the designer (private essays).
b) Trials are prints that are made usually on different papers before the start of the actual printing of the stamps, to check the proper function of the printing presses and inking units, the cleanliness of the printing plates etc. These also include colour separations for multicolour printing.
c) Machine proofs differ from trials as they do not represent the exact form of printing of particular stamps, but are used to test printing presses, especially new or repaired ones, which are used for printing stamp-like items. This term can also be used for prints that were made using the plates of earlier stamp issues, in an unchanged or modified form.
d) Essays are sketches produced in different designs at the request of the postal service, so as to find the most suitable of the designs intended for new postage stamps.
e) Proofs are the final trial prints made before the actual print run, in order to re-check the printing plate and colour rendition and to show the final design (if necessary in a different colour or value, by using a different printing process, or another type of print finish). The control prints, produced by the engraver during the preparation of the original die for the printing plate are also proofs.
f) Postage stamp prints which were intended to be issued as postage stamps, but for unforeseen reasons were withdrawn before being issued (often for political or technical design reasons), are regarded as “not issued”. They are listed in catalogues with der a separate (Roman) number as postage stamp prints.

Certificates or findings are issued for the listed items b) to f).

Printed or unprinted stamp-size areas
Unprinted or printed, rectangular perforated areas of paper of stamp size mostly occur due to imprecise cutting of a sheet.

Offset prints
Offset prints occur either due to the use (for sake of economy) of sheets of stamps that had been too weakly printed (e.g. Austria, 1850 issue) or the double-sided use of a freshly printed trial sheet, which was used again with the printed side down, thereby having part of the ink on the impression cylinder. Offset prints of the stamp design on the back are usually weak, but are however the right way round.
Offset prints (also overprints) are usually provided with certificates or findings.

Offset prints result if ink is delivered to the impression cylinder when the machine is idling and this is transferred to the back of the next sheet printed. Offset prints show a mirror-image of the stamp or parts of it. These are coincidences; they are not marked.

Collectors’ and dealers’ covers
Collectors’ and dealers’ covers are not commercially used items; they are covers that show the characteristics of proper postal handling, but were mainly produced for collecting purposes. This also includes covers that document technological or postal innovations, covers showing postmarks, air transport flights and such like. These covers may also be overfranked.

Specimens may be postage stamps which are marked with an identical handstamp or overprint, as specimens for the Universal Postal Union, the press, companies or public figures. Alternatively, according to the country or tradition, one might find such terms as “Muster”, “Muestra” or “Cancelled”, or simple forms of precancellation with stokes, crosses, bars etc. Specimens are not valid postage stamps, but sample copies of postage stamps intended for issue. Such prints are expertised only in exceptional cases.

Types of separation
In philately, imperforate stamps are only those which were officially issued without rouletting, perforation or puncturing.

The most common type of separation used in the production of postage stamps is perforation. Depending on the method of production it is referred to as line, comb, harrow, punched or ground perforation.

Rouletted stamps are those with which the paper between the stamps is partially cut with a fine blade, so that paper “bridges” remain between the individual cuts.
Types of roulette:
Line roulette, pin-perforation, zigzag, sawtooth and percé en arc roulette, occasionally coloured. Depending on the method of production, this separation process does not bring with it the same standards as perforation, with tooth-edged stamps. The separation is generally untidy and inaccurate. Therefore the separation is sometimes done with scissors despite the rouletting. As long as the separation with scissors has been done outside the printed area of the stamp and rouletting, this separation is considered flawless. Private roulettes are usually not expertised.

With ground perforation the printed paper web is pressed precisely against a stencil cylinder (pin cylinder) and the perforation is done with rapidly rotating multiple blades (milling cutter).

With punched perforations, the paper web passes over a die-cut cylinder (perforation punch) and the perforations are cut by a counter-pressing cylinder. Then the paper web is introduced to a second machine where the products (such as booklets) are punched out.
The separation may be of varying quality depending on the collecting area or issue. Separation which may in one collecting area be regarded as flawless might in another collecting area be regarded as flawed. The task of the expertiser is to consider these characteristics in making an assessment.

Misperforation refers to significant misplacement of perforation or rouletting away from the stamp. It is a random occurrence.

Stamps that were accidentally not perforated, rouletted or punched are regarded as varieties. They must have wide margins, so as to exclude any confusion with the perforated, rouletted or punched issues.
Partially perforated or rouletted stamps should show the full sheet margin or the complete adjacent stamp.

Unused postage stamps
Postage stamps with no form of postal cancellation are generally known as unused.

Stamps are described as “never hinged” or “unmounted mint” if they are not postmarked and have their original, unaffected gum in its original condition, taking into consideration the natural ageing process. Small finger- or handling marks generally do not affect this description.
In expertising, the marking of stamps has continued for well over one hundred years and will be indispensable in future for the overwhelming number of stamps. Expertising or owners’ marks are not considered a departure from mint condition.

Manufacturing-related gum impairments are not a defect. A private pencil signature on mint stamps is not regarded as a fault; it is only mentioned in the description.

Unused stamps are mint stamps that have their original gum coating with hinges, hinge remains or traces of adhesive. This also includes stamps from which hinges have been removed.

Stamps without gum or with partial gum are known as “unused”. Regummed stamps are regarded as equal to them in value, even though this is a form of faking.

Postage stamps which were issued without gum have their full integrity and value in this form. Postage stamps that were issued with partial gum are considered mint, if the gummed part is mint and the ungummed part is in its original state.

Self-adhesive postage stamps are regarded as unmounted mint if they are on the backing sheet. Changes in this definition are not be excluded in the event of future changes of the adhesive.

Misperforation – see Types of separation

Bund Philatelistischer Prüfer e. V.