Also on these boards
Cyanotype is a photographic printing process that gives a cyan-blue print. The process was popular in engineering circles well into the 20th century. The simple and low-cost process enabled them to produce large-scale copies of their work, referred to as blueprints.
After bleaching your item, soak it in white vinegar to neutralize the bleach. Otherwise, the bleach will keep "bleaching" and you will eventually get little holes....see comments at: grosgrainfabulous...