22c John J. Audubon Stamp (1985): How to Identify It

• Portrait source: Christopher Calle created the portrait, based on a painting by Audubon's son John Woodhouse Audubon held in the collections of the New York Historical Society.
• Standard series layout: a portrait, the word 'USA,' the denomination, and the person's name.

Audubon also appears on an earlier, unrelated 1c stamp from the 1940 Famous Americans series -- a different series, design, and denomination from this 1985 Great Americans 22c stamp.

• Measure the perforations with a gauge; the same design often exists in two or three gauges, and that is usually what separates the common one from the scarce one.
• Sheet, coil or booklet: coils have two straight edges on opposite sides; booklet panes have one or two straight edges from the pane edge.
• Tagging: hold it under a longwave UV lamp; tagged and untagged printings of the same design are listed separately.
• Condition (centering, gum, cancel) is a separate question from identification.

Lay the stamp flat on a dark background in daylight, fill the frame, and keep the phone parallel so the perforations are not distorted. Photograph the back too if there is a watermark or gum question. The app reads the design and denomination; the perforation and tagging checks above settle which listing it is.