The National Gallery's choice seems particularly prescient during the current quarantine; Lake Keitele is one of the most calming paintings that I can think of. Depicting a still lake in central Finland, the serene landscape with its dreamy reflections, dense pine treees and the silvery criss cross lines lying across the water, a phenomenon in the Northern hemisphere caused by currents and wind movements (or perhaps the wake of the boat of Finnish folkloric hero, Väinömöinen from the Kalevala epic), is deeply meditative.
Akseli Galllen-Kallela is Finland's great national painter and he painted during a time when Finland was enduring a period of increasing 'Russification'. Since the Finnish War of 1809, Finland was annexed to Russia as an autonomous Grand Duchy and at the end of the nineteenth and beginning of the twentieth centuries, Russia attempted to strengthen its foothold over Finland. Gallen-Kallela was a great Nationalist and during these uncertain political times, he consistantly promoted Finland and the natural beauty of his native land.
I still remember when this painting was sold at auction about twenty years ago. Lake Keitele has since then become one of the National Gallery's most loved paintings and the postcard is a best seller in the National Gallery shop. Under the current lockdown, you can only look at the work digitally but try admiring the work on screen and play some Sibelius while you do so. I hope that you find a moment of calm.