When I cleaned a flamed granite sidewalk the individual granite tiles all have a dark picture framing around them. What is this and how do I remove it?

The picture framing you describe is nothing more than moisture. As the tile dries the moisture is wicked to the edges of the tile. The picture framing will disappear as the tiles dry.

TIP Sometimes this picture framing will deposit salts and cause a permanent stain on the granite tiles. To determine if the picture framing is staining, take several moisture readings. If there is no moisture and the picture framing is present, you have a stain.