Both of these finishes are also anhydrous, which simply means they will absorb water. These white water marks generally can be removed fairly easily. Other finishes change chemically when they dry. The lacquer commonly used in commercial finishes these days is more often than not catalyzed lacquer. What this means is a catalytic agent is added to the lacquer to make it dry into a more durable finish.
Catalytic lacquers come in two varieties, pre and post.
Pre catalyzed lacquers have the catalytic agent added to the lacquer at the factory. Post catalyzed lacquers have the catalytic agent shipped in a separate container, for addition to the lacquer at the job site. Pre catalyzed lacquers are normally used by large manufacturers who can be assured of using up an open container before it's time is up. Post catalyzed lacquers are used by many refinishing shops because it allows them to mix up what they need at the time without wasting the rest, and at the same time getting a finish superior to ordinary nitrocellulose lacquer. You wouldn't want to use shellac on a dining room table top - it's too fragile to hold up.