We study a two-dimensional information design problem in a duopoly with vertical differentiation. A third-party designer, literal or metaphorical, designs a public joint signal structure to reveal product quality before firms compete in prices. The industry-optimal policy only reveals the quality ranking, which amplifies perceived differentiation, mitigates price competition, and yields socially optimal allocation. The consumer-optimal policy, to the contrary, intensifies competition by fully concealing the ranking. We further derive welfare-maximizing signal structures for arbitrary Pareto weights. The optimal policy takes one of the following forms: ranking, no-ranking, full revelation, or a combination of full revelation with either ranking or no-ranking policies. Our analysis illustrates how the optimal quality disclosure rule is shaped by both the relative weight on consumer welfare and industry profits and the price competition in response to the information revealed to consumers.