Any color can be matched, but not any wood. You have to pay attention to how the wood or woods you’re finishing compare to the sample you’re trying to match. 

There are four large categories of wood: softwoods like pine and fir; tight-grained hardwoods like maple, birch and cherry; medium-grained hardwoods like walnut and mahogany; and coarse-grained hardwoods like oak and ash. Within each of these categories, you can pretty successfully match any two woods using some combination of bleach and stain. But trying to match woods of two different categories has its limitations because of the large differences in grain and figure. To protect yourself, you should make your client aware of these limitations.