To my way of thinking, Sloan was one of those artists whose paintings became progressively less satisfying to view. His early works (which I might get around to discussing sometime) were pretty good, though not distinctive. Mid-career paintings were less well done, in my opinion, but were distinctively Sloans, which is not a bad thing when it comes to long-term artistic notoriety, if not fame. During the last 20 or so years of his life, Sloan went off the rails and began using tempera paints to create underpaintings featuring topographical-like lines describing a subject's surface, much like the sort of engravings one sees on paper money. Atop that base, he applied oil paint glazes. I show some results below.
Above are two mid-period Sloans to set the scene. When one thinks of Sloan, this is the general style that is most likely to come to mind.
A fairly early topographical Sloan effort. The surface definition lines are mostly on the subject, not so much on the setting.
Two portraits. I have no idea why Sloan persisted with this style when it should have been obvious that resulting works were rather ugly. The technique is so strong and odd that it easily distracts viewers from the subject matter.
A late painting illustrating Sloan's stylistic obsession applied to an entire human form.