Lars, Thanks. Ofcourse it is nice when people can enjoy it for a longer period of time but I also like it when the image changes in front of you as you were watching a film.
Thats why I would like the proces go a bit faster. (maybe change black between 10 min and an hour?)
I attempted something similar to this with some salt prints in exhibition and featured in an article “A Sideways Movement in Time” published in the Photographic Journal. I see what you are trying to do and it is an interesting challenge, but I think without some sort of chemical pod that bursts and spreads developer over the print as it is pulled out of the envelope, this will be difficult to achieve.