After sketching and 'stickyframing', I usually make HTML prototypes.

I'm now thinking it might be a good idea to add classes '1', '2', & '3', allowing elements to be prioritised. A standard style sheet can then be added for applying the kind of shading illustrated here.

Nice and simple.

"Photography could not only allow for the various interface states to be frozen as a future reference."

I currently photograph every iteration of a given screen (i.e. every time someone ammends a screen, I photograph it). But I also really like the idea of using photography to capture every state too.

Thanks again for the thoughtful article, Jakub.