This ceramic tile was installed less than 1 year from this photo. Tile, like carpet, can show soiling and traffic lanes easlily. Two people and one dog live in this home. Everyday traffic, combined with dust and oils a pet may bring in can attribute to a 'dingy' surface on tile. Grout lines, in high traffic areas, will appear darker than in corners of rooms, or where people do not walk. The darker grout shows absorbtion of dirt, foods, and or oils. Go ahead, look in your hallway or kitchen and notice that along the edges, the grout is lighter than in the center of traffic.