Many (but not all) of my sepia-toned images are shot as IR images in black and white, then hand-toned to produce the sepia-toned effect. I can't tell you how I decide which to leave as black-and-white, and which to transform with the sepia tone... there's no rhyme or reason. I've also experimented with hand-coloring parts of the image (as in the arrow in the Claes Oldenburg/Coosje van Bruggen "Cupid's Span" scupture in the middle row).

Many of these images were shot with a Hoya IR filter, then hand-toned.