Lyonel Feininger work

First off, I love both Lyonel Feininger's work and that of his one son T Lux. His work is often confused with Duchamp but for Feiningers reliance on points of light and a horizon

If you have an original and its listed , does the listed painting have a place in which its hung? If so, is that a work in which Feininger diid a couple of versions? (Many artists would do studies an sometimes do multiple works of a similar nature)

If its an original (even if its not by Feininger) does it show real brush marks (not those fake ones they stick on giclees)? If you shine an ultraviolet light on it do the blues and whites actually fluoresce differently? (That indicaes differing pigments and not just a print.
IF its a print, see whether theres a name signed in the paper block around the painting subject. (That means the artist, even though its a print, had a hand in the printing , or at least approved it.

Good luck, If its a real painting, his work is in the high 5 figures to low million dollar range

Some not so good news for thi inquiry.
Apparently your original is an oil and its hung at the Museum Boijman van Breuningen in Rotterdam. You probably have a print or a poster of it, Im thinking a poster since his works weren't run in discrete small bunches with his approval and most of the were printed in the 1980s (30 years after the old man died), Maybe T Lux or his other son had the posters run as a fund raiser.
Apparently the posters arenot really valuable .

Well? any ideas about your artwork?