Reto Kaul is a young (20 yr old) freelance concept artist and illustrator from Switzerland. His web site lists his work experience as concept design, book illustration, covers and fashion design, but doesn’t list specific credits. His portfolio, however, has some nicely atmospheric pieces that show off his talent for dealing with muted light in particular.
His imaginative landscapes and imaginary cityscapes are often cast in compositions with analogous color schemes, largely blues and greens. He likes to punctuate his thick atmospheres with sharp pinpoints of light, and loves to play with the idea of faintly visible shafts of light, fanning out at they emerge through the canopies of trees, break through layers of clouds or splash around a prominence of rock.
He has a nicely balanced command of his digital tools and his pieces have suggestions of texture and detail without being overworked.
His online gallery is a little shy on information about the pieces, but if you hover your mouse over the thumbnails you’ll get a “tool tip” style pop-up with the name of the piece.
You can also find more info about the images (and some larger images) on some of the various concept art sites where he has a presence under the handle “gizmodus”.
Mirandopolis: Museum of Modern Art (image above, with detail, bottom, larger image here) is part of a series in which the museums of the imaginary city (no relation, I assume, to the actual municipality of Mirandópolis in Brazil) are pictured as built in a gigantic cave.