Thank you for submitting your item for appraisal. This appears to be a small painting by Kevin Charles (Pro) Hart (1928 - 2006), a grisaille depicting a dragon fly, signed lower left. In general black / white paintings sell less well than colourful paintings. Paintings by this australian artist are sold at auction once in a while and the painting in your possession is well in the parameters of the artist´s work, though I can´t authenticate this painting. The estimate is based on auction results. "Asking prices" in the trade might be higher and vary.