Mounting: For best results you want your tissue to be centered within the bounds of a single coverslip. You can place more than one section under one coverslip as long as the edge of the coverslip does not overlap the tissue. You will be able to see where the coverslips ends and if this is too close to your tissue it can negatively impact your tissue imaging in that area. Additionally, make sure that your mounting medium completely covers the entire area under the coverslip. Areas without mounting medium will not be in focus and it will be impossible for us to correct this. 

Hydrophobic pen: Hydrophobic pens are a great tool to use when prepping your samples. However, the pen marks do fluoresce and therefore if the lines overlap the tissue it will make the tissue in those areas impossible to image. If you are seeing hydrophobic pen in your imaging - we reccomend leaving more space around the tissue.