How to grade stamps and the impact condition has on value

To carry out stamp grading accurately, a degree of specialist philatelic knowledge is required. But even if you enjoy collecting stamps as a hobby rather than as an investment, you can still learn about the many different factors that must be considered when trying to determine a stamp’s value.

The best philatelic experts use a defined set of criteria to conduct each postage stamp grading.

The factors to consider when grading a stamp are:

  • Condition
  • Gum
  • Centring
  • Margins
  • Perforations
  • Marginal details
  • Faults – such as creases or tears
  • Re-perforation or repair
  • Colouration - fading or stains
  • Cancellations

Only when an assessment has been carried out on every unique feature of a stamp can a judgement be made on its overall condition, which will then determine its value. Obviously, a stamp which is classed as a superb example will be worth more than those of lesser quality. Whilst it is important to carefully consider a stamp’s condition and its impact on price, the value of a stamp is ultimately defined by what someone is prepared to pay for it. So, if you do find an item which takes your fancy, make sure you add it to your collection before someone else does.

A unique british stamp: The only known example of the GB 1967 Discoveries 1/9d “missing gold (Queen’s head)” as sold here at Warwick & Warwick in December 2014, realising £23,600 including the buyers' premium.

Are used or unused stamps best?

Gum condition: Whilst evaluating mint stamps it is important to take in to account the condition of its gum (the adhesive on the reverse).

When talking about gum, the optimum condition is for it to be in exactly the same condition as the day it was purchased from the Post Office.

Some collectors will not purchase stamps unless they have pristine gum, whilst others do not even consider the rear of a stamp when on the hunt for a new piece. Although it doesn’t matter which camp you fall into, it is worth knowing the impact that gum condition will have on price. A basic rule of thumb is: the more genuine gum which is present and the better the condition of it, the more a stamp will be worth.

Hinges: Mounting mint stamps with stamp hinges may reduce their value.

If a stamp has been hinged several times or if a hinge is still attached, the stamp’s value could be worth around 50 per cent compared to when in full ‘mint’ condition. Generally, a stamp which has clear and unblemished gum will be worth more. As condition deteriorates, its value will decline accordingly.

Stamps which are in unmounted mint condition are the most highly prized, and older stamps are obviously less likely to be available in ‘unmounted’ condition so there is a premium price attached to them.

For stamps issued after 1965, there is limited demand for mounted examples – unless they are extremely rare or very desirable sets.

Discolouration of gum: Although the presence of a hinge can dramatically affect a stamp’s price, any browning or discolouration of the gum is also significant. Stamps which have discoloured or cracked gum are worth less.

Re-gummed stamps: As unmounted mint stamps are more desirable, and are therefore more in demand, the practice of adding new gum in place of the original has developed.

Although ‘re-gumming’ is not an issue if the stamp in question is sold as such, in many cases it has been carried out to obtain a higher price.

To protect yourself from paying premium prices for an inferior piece, it is therefore essential to carefully scrutinise every edge of a ‘mint’ stamp to ensure there are no traces of gum on the surface.

Our policy here at Warwick & Warwick is only to sell re-gummed stamps with an appropriate statement of condition.

A very rare stamp: A great example of the 1910 2d Tyrian plum of Great Britain, which realised £48,300 when sold here at Warwick & Warwick in October 2012.

Centring, margins and perforations

Why centring is a key factor in determining a stamp’s value.

Centring is the term used by philatelic enthusiasts to describe how well the pictorial design of a stamp is positioned within the edges or perforations of a stamp.

Although this element of the stamp grading process is somewhat in the eye of the beholder, most philatelists want to add stamps that are perfectly centred to their collection – making it a most important factor in a stamp’s value.

When a stamp is said to be ‘well centred’ it means that all four sides of the area outside the printed pictorial design are exactly one half of the distance between two adjoining stamps.

On rare occasions, a stamp with jumbo margins – where it has ‘stolen’ part of the margin area from those adjacent to it, can fetch up to double the amount it is they are usually worth.

When analysing stamps which have been graded for sale, look closely at the pictures and try to judge how that dealer grades his items. If you agree with their centring accuracy, a judgment can then be made in terms of the asking price.

Wing margins: Sheets of stamps may be made up of two or more panes with a narrow gutter between them. Wing marginal stamps are those positioned on the edge of the gutter and have an extended margin on one side. Such stamps were once seen as less desirable but are now of similar value to normal stamps of the same design.

Rare perforations: A Jamaica 1938-52 5/- marginal with line perforation and an intersection of the horizontal and vertical perforations which are not coincident - shown in detail in the lower right corner of the stamp.

Perforations: There are two factors to consider when looking at the impact which perforations have on a stamp's value:

Centring of the stamp’s image within the perforations: A perfect stamp should boast an equal space between the edge of its pictorial design and the perforations around it, on all sides.

Early stamps are rarely found with perfect centring because of the printing methods which were used at that time. If a rare stamp is ‘slightly off centre’ it can therefore still be classed as desirable but only if the perforations are not touching the pictorial design.

Early perforating machines were inaccurate so stamps can vary massively in size. Stamps which are ‘oversized’ can be worth a premium and often realise high prices at auction.

If a stamp’s design touches the perforations, it is worth a lower price and generally the bigger the displacement, the less it is worth. If however the displacement is extreme: the stamp may be considered a scarcer variety and be worth more as a result.

Condition of the perforations: Perforations damage easily, and if a perforation is ‘nibbled’ or slightly short, a stamp becomes correspondingly devalued. The more ‘teeth’ which are affected, the less a stamp is worth.

The term ‘pulled perf’ is used frequently in philatelic circles and means there is a gap where a perforation tooth has been pulled away. A ‘short perf’ or a ‘short corner’ means that a stamp has part of a perforation or corner perforation missing and the stamp can only command a lower asking price.

As the gauge (number of perforations) increases, the impact of short perfs on value also increases – ranging from a discount of between 20 and 50 per cent of its full ‘mint’ value.

Paying a premium for marginal details: The first British stamps came with inscribed ‘sheet margins’ which offered advice for the public about their price and where to place them on a letter.

Rare stamps with sheet margins which include a control number, plate number or printer’s imprint will greatly enhance an item’s value. For example, the highly sought-after Penny Black or Penny Red with a sheet margin might be worth between 50 and 100 per cent more than a normal ‘mint’ example.

However, in most cases, a sheet margin does not have a significant impact on the value of the stamps to which they are attached.

Faults and Damage

Any stamps which are damaged or have had their appearance altered are generally of lesser value.

There are a number of recognised faults that can affect a stamp’s value and any of the following will reduce its worth:

  • Changes in colour
  • Non-postal cancellations
  • Thins
  • Holes
  • Tears
  • Repairs

Depending on the severity and type of fault, a collectable stamp can still command a good price. However, the more obvious the damage is, the greater impact it will have on overall value.

Bends: Any ‘bend’ can reduce a stamp’s value by 10 or 15 per cent, even though it is usually only visible from the back.

Creases: If a ‘crease’ is clearly visible on the front of a stamp, expect it to be worth between 10 and 20 per cent of its ‘mint’ value – depending on the severity of the crease and its location on the design. A series of light creases or ‘wrinkles’ will also devalue a stamp but less significantly.

Thins: Stamps which show signs of ‘rubbing’ or a ‘thin’ area are also worth less, depending on the severity of the damage. A hinge fault is obviously less serious than a central abrasion, so the impact on value should be judged accordingly.

Perforated initials: Stamps with perforated initials, a process which was carried out to discourage theft, are now proving very popular with collectors – unlike in the past when they were viewed negatively.

Sometimes referred to as perfins they are often worth a similar amount to normal used issues.

Fading or discolouration: It doesn’t matter whether a colour change has been caused by water or sunlight, the impact on a stamp’s value is still significant. Realistically, even a highly-desirable rare stamp with discolouration is only worth up to 20 per cent of its mint value whereas more common items are almost worthless if severely faded.

Tone spots: If a stamp has a ‘tone spot’ or brown marks which disfigure its design they are of reduced value. Often this results from poor storage and highlights the importance of looking after your collection.

The more severe the toning and the more prominent the location, the less the stamp will be worth. Even a rare issue with a small spot in its centre will be devalued by around 25 to 50 per cent compared to the same stamp in fine condition. Modern stamps with toning faults effectively have no value at all.

Penny Black: A superb example of a valuable Penny Black, with a Maltese Cross cancellation specific to Wotton-under-Edge, which was discovered by the keen eye of our senior stamp valuer Joseph Cottriall back in 2015.


When do they make a stamp worth more in value?

Philatelic collectors will be very familiar with the term cancellation, which describes any postmark or ‘obliteration’ technique intended to prevent a stamp from being reused.

Although heavily cancelled stamps are usually worth considerably less, because they detract from the visual appearance, this is not true of all cancellations. In fact, there are cases where the cancellation is actually worth more than the stamp to which it has been applied.

Essentially, the aim for collectors who are keen on cancellations is to find stamps with unusual and scare postmarks. For example, a Wotton-under-Edge Maltese cross is worth more as a ‘fine’ or ‘full cancellation’ (where the mark has been strongly made but the design remains clear) as opposed to one which has been applied lightly.

Postmark collectors are generally interested in where and when a stamp was cancelled. However, any cancellation marks should be lightly applied, displayed in full and well centred to fall into the top category.

A christmas cancellation: A magnificent, complete and colourful type 2 1903 Leicester cancel in red, which realised £264 when sold here at Warwick & Warwick.

Get expert assistance when grading stamps

Although there is a lot to learn when it comes to grading stamps, most philatelic collectors do master the basics (and usually a whole lot more) during the course of what is usually viewed as a lifetime hobby.

For that reason, there is no rush to learn every aspect. Acquiring knowledge on a need-to-know basis is a big part of the stamp collecting journey.

To discover more about the terms used by philatelists, we have created a handy guide which explains all of the stamp terminology in detail. This will undoubtedly help you when it comes to grading stamps accurately.

There are also a number of other organisations and philatelic forums where likeminded collectors are happy to share their experience.

If you would like to get an expert opinion on a stamp you own, one you’d like to buy or a collection which may have come into your possession, our specialists would be honoured to provide their assistance. Please call 01926 499031 or send an email with your contact details so that we can get in touch.

But the most important thing for collectors to remember is why they got into the hobby in the first place – for their love of beautiful stamps and the sheer enjoyment they get from collecting them.

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