Just trying to pick some brains and see if anyone has seen any picture framing when cleaning ceramic tile. This first happened to me last month. Customer wasn't concerned but I sure was. She was happy her floors were cleaned. I originally used acid but even switching to alkaline it still happened. Fast forward to today and this happened again at a different house. Thank God I only did a little area and the lady is old. So these were spanish ceramic wood plank tiles. I saw the box left over. Both customers had the same color and type of tile. I don't know if this is a moisture issue or what. Anyone see this yet? If not keep your eyes out. Seems to happen on tan wood plank looking tile.