The historical process I choose to work with was Cyanotype.
For this process potassium ferricyanide and ammonium ferric nitrate were mixed at a 50% ratio.
This solution was then applied to canvas and left to dry in a dark cupboard, once dry, a negative image on acetate was applied to the canvas and held in place in a glass frame, this was taken outside to develop in the sun for approx 10 to 12 minutes. Once developed it was rinsed under cold water to remove all the residue and then put into a tray of hydrogen peroxide to darken the image where required.
Developing In the Sun
One of the finish results taken on mobile phone