A very fine used example of the 1/- gray on blue green King George V stamps from the 1914-1922 De La Rue Imperium keyplate design, multiple crown CA watermark on chalky paper, with a pale olive backing. The SON cancel is from Old Calabar River, and is dated April 28th 1920.
Included in the photos is a scan of every different paper back found for this paper color.
Gibbons lists this very fine used example at 48 pounds, (approximately $96). The stamp offered here grades 84 as follows:
