2 cups flour, 1 cup salt, cold water. Mix until has consistency of play dough. Imprint & Bake at 250 for 2 hours, then cool and spray with metallic paint.
I wouldn't do baby feet but maybe dog or cat paws!.... Salt Dough - 1 cup salt, 1 cup plain flour, up to 1/2 cup of water. Mix together and knead until smooth and stretchy. Add more flour if too sticky and more water if too crumbly. For a footprint 3 hours @ 100 degrees C or 200 F. Cool for 2 hours for smaller things, e.g. Xmas decorations or letters