Rare vs uncommon

What criteria does one use to ascribe a rarity status to a stamp?

There is no consensus.

Is it the very scarce number of the particular stamp or postmark in existence?

Or does it pertained to a much desired item, tightly held, such that it is not easily acquired?

However, the rarity of an item does not equate to value.

It all depends on the desirability, the difficult in acquiring and the so called market forces.

For some popular countries like GB and USA, their stamps are always going to be more desirable and more valuable in general regardless of scarcity.

Where an individual stamp is concerned, condition, condition and condition dictates value unless it is unique.

I would personally consider a stamp or postmark to be rare if only a score or so copies are in existence and very rare as less than ten.

Otherwise, it is generally safer to describe such items as uncommon or very uncommon.

And some rare examples in our territories would include:  

North Borneo, SG1a imperf between horizontal pair-2 copies

North Borneo, SG54a large "s" in "cents" overprint-1 copy etc

North Borneo postmarks, Sipitang,  Jesselton BNBC, Gantian, Kudat P and cancelled at Brooketon etc

Labuan SG 22 "One Dollar A.S.H.", SG142 $10 Labuan overprint etc

The famous Labuan 8c postage due frame inverted, using the criteria, can only be described as very uncommon. It maintains its value very well because it is probably the most popular stamp of Labuan.

Straits Settlements, Hong Kong and Indian stamps used at Labuan, Labuan D1 and D2 etc

Brunei prewar Seria and curved year Belait and Tutong cancellations etc

Sarawak 1876 "TWO CENTS" surcharge on SG2 etc

Sarawak early manuscript town cancellations, Betong type 1, Paku, Pusa type 1

etc

These are some obvious candidates and is definitely not a comprehensive list.

What is rare today may not be so in the future due to continuing new discoveries.
On a similar vein, readers may like to read a posting from a few years ago discussing "What is a postmark?" by clicking on the link here.

Some postcards of Labuan

This is a rather uncommon postcard of Labuan from the Sanbride series. So far I know, there are 5 different Sanbride postcards of Labuan dating from the early 1900s. These are identified by the lego on the back which divides it into the message and address part. This would help to date it post 1906 as prior to that, writing a message on the address side would warrant a letter rate which is higher. Before this date, messages were written on the picture side. 

You can find out more about "Sanbride" and "postcards" by typing these words separately in the search facility box at the top left hand corner of this page. And for readers whose first language is not English, there is also Google translate near the top right hand side. 

These two postcards show the same scene. The top card is older and probably dated from the early 1900s whereas the second card was printed 10 or so years later. These cards were not photographs but printed by lithography using 6-15 colours from an original black and white photograph. It was invented by the Swiss Hans Jakob Schmid during the 1880s. They are known as photochrom prints and were very popular between 1890 and 1910. The main difference between these 2 prints, apart from the colour, is the sky has been redrawn in the bottom card.   

The back of the postcards confirms that the upper card is older without a dividing line on the address side. The other card was published by Max Hilckes of Singapore using the same original photograph. Their earlier output were in B&W and the coloured ones probably came after 1910.

This book written by an Australian academic, published in 2017, is a good comprehensive reference. Several of my items are illustrated within the book. But what surprised me is the postcard on the cover is exactly the same as the one that I have for quite a few years as seen by the defects on the right side of the card. 

This postcard is rare. It is a real photo postcard which by definition means there was a very limited run or even possibly unique. It is essentially the same scene with some differences. It is probably a reprint from the negative of the earlier photograph than the other two postcards. The 3 small trees in the later cards were only saplings here.

In addition, this postcard was sent using a North Borneo stamp in 1908 when Labuan was already part of the Straits Settlements. This usage can only be valid if it was paquebot mail posted on a boat on its way to Labuan from a port in North Borneo.