Nicholas Lindan
Advertiser
FWIW - I stapled a tannin-toned cyanotype to the deck railing for a year. It was a mostly sunny location (er, Cleveland 'sunny', which isn't all that much sun TTTT). No fading, but it did take on a 'silvered' gray tone rather than the purple-brown of a a freshly toned c'type. Paper was Bienfang 360 (the original paper, not the newer version). The paper didn't loose any strength in the ordeal.