The cyanotype blueprint was the standard reprographic process for architectural and engineering drawings from the late nineteenth century well into the twentieth. A ferric-sensitized sheet was exposed to ultraviolet light and washed in water, fixing a deep Prussian-blue ground while the drawn lines — shielded from exposure — survived as crisp white linework.

The result is an instantly legible engineering language: white hairlines, dimension callouts, witness lines, title-block tables and revision clouds laid over saturated blue. This system reads that artifact literally — paper-white ink on blueprint blue, set in narrow drafting grotesques and technical monospace, with not a single rounded or decorative gesture.