What are rectified tiles?

When a tile is “rectified” its edges are cut at the factory after it is baked. The natural, pressed and somewhat rounded edges of the tile are cut and machined to produce a fairly sharp, precise edge with a micro-bevel and a flat surface at the perimeter. This procedure is common for porcelain floor tile but is also sometimes performed on large format ceramic wall tiles. With this precision the tiles can be set with a 2 mm to 3 mm grout joint and due to the flatness at the edges the joints are less visible.