Moreover, can you paint over a wood finish?
As long as you sand the wood with at least a 150 grit sandpaper, you can use acrylic paint on stained wood.
Additionally, what kind of paint can you use on finished wood? For furniture it's best to use a satin or semigloss finish in either a latex or an oil-based paint. Never leave primer unpainted. If you choose a latex paint, a latex primer is an excellent choice for most uses. It goes on easily and blocks most stains, but it doesn't have the odor of an oil-based primer.
Keeping this in consideration, how do you change the color of varnished wood?
In the past we've used a paint wash (water mixed with paint) to tone down the color of wood finishes. But to be most effective, this requires some sanding. The advantage of using Color & Seal is that is allows the grain to still show through AND it seals it at the same time.
What happens if you don't sand before staining?
A lot of folks make the mistake of sanding to either too fine of a grit or not fine enough before applying stain. Too fine and the wood won't be able to accept the stain. Too rough and the wood will be very dark almost to the point of being black.