Shikabane Shoujo To Kakanai Gaka

From Oblivion Lumiere:
Everything happened after the death of a genius lady painter. The Professor, who cannot give her talent up to nothingness, planted her soul into a young girl’s corpse. Youth painter Nell is then asked to teach the girl, “Lili,” how to paint…… The undying girl and the shut-in youth painter; the peaceful days of these two wandering in the ravine between life and death are… Don’t miss out on this tale of a little mysterious yet beautiful “soul” drawn in a stunning art style!