Cyanotype is an early photographic printing process that produces a cyan-blue print (it's were the term 'blueprint' comes from).

The process uses two chemicals: ammonium iron(III) citrate and potassium ferricyanide, applied (in my case painted) onto paper, dried (in the dark) and then exposed to sunlight with the object placed directly to the coated paper.

In this case some pressed autumn leaves were placed onto coated Khadi 100% cotton rag handmade acid free paper and exposed to the sun, washed and dried.