In general, wireframes should be done in shades of black, white, and gray. Grayscale wireframes imply that the design isn’t finished, making it easier to throw away designs that aren’t working and try again. They also give the same impression to clients and other stakeholders, who will be more willing to give creative feedback if they feel like the wireframe is just an early prototype.

That said, there are instances where color in wireframes can be useful. If you need to show a client that their existing color palette isn’t going to work for the design, need to show contrast in certain situations, or feel like color usage will help get buy-in for your designs, then using color may be the right choice.^[1]