Came from the slave days, and was considered a medical disease which needed curing if a slave was wanting to escape. So, metaphorically speaking, this word can be used as a noun if you feel trapped and ache for escape. on Travel quotes quotes
"Though this picture is simple. I have done black and white photography for many years and my favorite element of design is contrast. The contrast in this photo takes it from simple to interesting." I think this a fine example of contrast/black and white.