Well, the overcoating brush used in Polaroid prints is a form of shutdown, but beyond that there can be a polymeric acid layer protected by a water repellanat layer. The base in the pod breaks down the repellant layer and is then further neutralized to the proper pH by the acid layer.

This is necessary in integral materials and sometimes optional in non-integral materials.

If you have a peel-apart material, the individual customer can be burned or harmed by the alkali or the other chemistry.

Without proper pH and removal of harmful chemicals, the image may 'tone' and turn brown or otherwise change in density.

This is why I bring it up.