Final answer:
The correct term for restoring a Renaissance painting to its original state is 'restoration,' which involves using non-original material to return an artwork to an earlier appearance.
Step-by-step explanation:
The term that refers to the process of restoring a Renaissance painting to its original look is called restoration. Restoration in the context of art generally involves returning a painting or object to an earlier state, often through the use of non-original material that is detectable and ideally, reversible.
This differs from conservation, which involves preserving the current state of an artwork, making repairs that are visible yet not distracting to the viewer, rather than attempting to revert it back to its original appearance.