varieties

One of the most exciting aspect of stamp collecting is to discover an unnoticed variety in one's collection. I have scanned some examples. You certainly need good eyes or a magnifier to spot the BORNEQ error in the  Malayan Borneo Exhibition 1922 stamp.  The large "S" in the 6 cents overprint is clearly seen when compared to the normal. It is easy to miss on its own.You will need to click on the 50c pair of stamps to see the error Jessleton instead of  Jesselton. There is definitely a lack of  detail and quality with these more modern stamps using the photogravure process.

1890 and 1892 surcharges

The overprints were said to be done to a lack of the 2c and 8c stamps at the time. The first printing had 3.5mm between the lines of surcharge. A second printing was made some years later with the space between at 5mm. Again with NB stamps, the reasons for doing so are unknown except to serve a philatelic purpose. The "8 cents" surcharge was made purely for the pleasure of collectors as there was no need for a stamp of this denomination in 1892 when the international letter rate has been reduced to 6c. It is relatively uncommon as apparently only 300 stamps were overprinted.