So what do we mean by undermount sink reveals? A picture best shows this... Below shows you a "positive reveal" and a "negative reveal" around an undermount sink. And yes, there is such a thing as a "zero reveal" where the countertop is flush with edge of the sink. The countertop runs short of the undermount sink flange edge with a positive reveal. The countertop runs past the edge of the undermount flange with a negative reveal. Which reveal is used most often? Probably the "negative reveal". Generally, the positive and negative sink reveals have no up-charge. However, the zero reveal will likely have an up-charge.
Positive Undermount Sink Reveal
Negative Undermount Sink Reveal
