I also acquired in my US stash a 2 cent George Washington (R6 I believe) Is it correct that this was a stamp used as a luxury stamp. Would it have been used for writing a check or payment tax for a photograph ? Thanks for the helpful information...
It is what is known as "revenue stamped paper". It appeared on a number of different types of financial documents starting in 1862. The tax collected was used to pay for The Civil War. It was not a luxury tax. The tax on checks ended in 1883. The use of revenue stamped paper resumed during The Spanish American War.
The tax on playing cards was included in the revenue stamps issued during The Civil War. The tax continued on until 1965 as a "sin" tax.
The Scott United States Specialized Catalog has an introduction to each revenue stamp category that describes, to varying degrees, what the revenue stamps were used for.
As a sideline, the History Channel has a series called "Decoding the Past". It is an interesting series. One of the episodes is about playing cards, and how they came to be.