As you can see, you see nothing - except gray, noise due to underexposure, and then a blurry spot, but it could also be a bright lint casting a shadow. … a tip Off Topic: Such damages or defects should be photographed in a way that allows the exact location to be identified a) in the room b) in the tub (top, side, bottom) The measuring tape, which should be placed on the damage, should also be visible in the overviews. Yes, and then focus: one should be able to recognize the outlines and what you describe.