On those early-1800s 1-piece "flat buttons," there are literally dozens and dozens of variations of the quality rating stated in the backmark. The fully-stated version of your button's quality rating is "Imperial Standard Quality." For reasons of economy in labor costs (and on smaller buttons, limited writing space), abbreviations were often used.
Stand'd is one such abbreviation. On your button, the manufacturer simply used the word Imperial. Customers knew what that one word meant.
You wrote:
> If anybody knows more id appreciate it.
Your backmark is written in "indented" letters (not raised), which on 1-piece flat buttons means the button dates from approximately the early-1810s through the early-1840s.
The word London on your American-dug button's markmark means it was made in Britain and imported into the US sometime between approximately 1820 and the early-1830s. The reason such buttons were imported is that the American button industry was unable to produce enough buttons to satisfy the demand-level from the Clothing industry until the mid-1830s. (The War Of 1812 caused American customers to dislike doing business with the British during the war and for several years afterward.)
