Shrinkable modelling materials?

Hi all,
I was wondering if anyone knows of a shrinkable modeling or casting material that i could use to make some detailed elements at a comfortable size, then have them shrink without looseing too much detail? For example if i could model a face say 5-6cm high and have it shrink maybe to 1cm high or even less.

most moulding solutions or vulcanising processes give up to 5-10% shrinkage on the mould. In terms of scale a 1cm scale down is quite a bit. it would be easier to send it to a moulding company and ask them to scale it down using jewel cad and print the result out in wax for you.