20 Dollars Colonial Bank

The Colonial Bank was a British-chartered institution operating primarily across the British West Indies and British Guiana, eventually absorbed into Barclays Bank (Dominion, Colonial and Overseas) in 1926. Notes of this period were printed in London and shipped to branch offices for issue — the bank itself had no local printing capacity.

Perkins, Bacon had been producing security printing for colonial banking clients since the mid-nineteenth century, using steel-intaglio techniques originally refined for postage stamps. Their work is generally resistant to amateur counterfeiting, which suited issuers whose circulation territories had limited detection infrastructure.

The S-prefix in the Pick reference denotes a private commercial bank issue rather than a government or central bank obligation.