When we installed tile, we did not do anything to the tile as we liked "the natural look." A big mistake. The gout is different colors. I had a large rug in the dining room; when I moved the rug out this summer. the tile is now lighter than the area where rug covered the tile. I now have dark tile around where the rug was and of course, the lighter tiles where the rug was. Have not a clue what to do at this point.