Cyanotype lifespan

[bblhed]

The issue with stone is the size. Limeted space in the time capsule you know.

What about glass?

You can get stone cut and shaped you know, A piece of stone the thickness of a piece of glass can be done easily, they may even have some at your local home store. You might have to clean it up to give the surface you want, but stone is doable. Remember that stone can be more fragile than glass.

[BrianShaw]

How did you sensitize the area on the sidewalk? And did you coat it afterward? Or was it exposed to foot traffic?

Thanks for asking... it was a fun experiment.

I just dumped sensitizer on the sidewalk and covered it up until it was dried. Then put a neg on top (I had a very large -- maybe 24 x 36 copy neg at the time) and exposed. Then hosed off with a garden hose. Nothing more. It was in a part of the sidewalk that was basically unused but had sun exposure during the entire day -- all year long.

[michaelbsc]

Was the sidewalk freshly poured, green concrete? Or well set already?

I want to make 18x18 decorative paving stones.

If they get foot traffic then I would need some clear sealer on top to prevent wear, too.

Maybe this deserves it's own thread.

[BrianShaw]

Was the sidewalk freshly poured, green concrete? Or well set already?

I want to make 18x18 decorative paving stones.

If they get foot traffic then I would need some clear sealer on top to prevent wear, too.

Maybe this deserves it's own thread.

Well set. The sidewalk was probably 20 or 25 years old at the time.

In addition to its own thread, I think this concept could use some good (rigorous) experimentation. I also wonder if a sealant prior to coating could help also.

[michaelbsc]

...sealant prior to coating could help also.

Actually I was thinking the other direction. Concrete is full of ferric compounds. If you're working with it green one generally works the dyes into the top few mm of the surface.

If a way can be found to exploit the ferric chemistry of concrete into a natural sensitized layer then it is part of the surface, not just sitting on top of the surface.

Of course, there is a real possibility that the other reactions going on to set the concrete would wreck any light sensitivity. But it sure sounds worth trying.

[Nicholas Lindan]

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.