For this picture, I decided to use Topaz Labs' Black & White Effects, which is an ENORMOUS suite of filters in black and white and mono- and duo-tones, plus many specialized filters too. Powerful, fun, ultimately customizable, I always love to have the excuse to use this fine set of filters! This particular filter was in their Cyanotype collection, called "Yale Sky."

By the way, if you're interested in trying this amazing set of filters out, Topaz gives out free trials to let you try their products. If you like playing in black and white, you will LOVE these filters!! Topaz Labs: Product Downloads