This is an Official Marvel Comics ONE OF A KIND original colorist art/color guide page used in the direct production of the vintage CAPTAIN AMERICA issue 284 comic book from 1983. This 1980's story featured art by silver age and bronze age artist SAL BUSCEMA, and the Marvel colorist for this story was Bob Sharen. This is the ONLY color guide of this page in existence (it's 1 of a kind), and it was used in the production of the actual published comic book by Marvel's Production Staff.
NOTE: As you can see from the scan, the shape of this color guide page is not perfectly even, and this is common with hand-painted colorist's artwork. Back in those days, color guide art pages were never expected to be saved, handled gently by Marvel's Production Staff, or collected many years later. This is normal for production artwork like color guide colorist's art.
NOTE: Color guide artwork is different from black and white original art. Color guides (colorist's artwork) are re-sized copies of the pencil and ink original artwork that are assigned to the issue's colorist, and then hand colored by that colorist. Colorguides usually measure about the same size as the published comic book, and some have "color codes" for the printers to follow. Because most modern comic books are now colored by using computers, there are no more color guide pages being produced, which makes the surviving color guide pages highly collectible. This description is (C) RLC.