Posted By Stephen R Robinson Hi all Asbestos Consultants, During a recent UKAS visit, I went through microscope set up. One querie that came up was in order to say you can see Band 5 of the NPL test slide, how many of the lines do you have to be able to see? I always thought you only had to see one complete line from one tramline to the other to class Band 5 as visible, not all ten. The guidance state that band 5 should be visible, but not how much of it should be visible. Could someone please help me clarify this point? Cheers, Stephen