Assume we have a surface $S$ (smooth if you want), and a map $f: S \to V$ that contracts a a curve $C \subset S$. What What condition would give a factoring of $f$ through a contraction $c : V \to V'$ $c: S \to V'$ contracting $X$ and is isomorphic$C$ but otherwise being an isomorphism?
What about the special case where $S$ is a flat family of curves and $X$$C$ is the central fiber (all other fibers are assumed smooth). What criterion would give a factoring of $f$ through the the contraction?