Daylight blue filters produce a desirable background to balance out the brightness of the light. The blue microscope filter is often used with microscopes that have a halogen light in them, as the halogen light tends to have a more yellow hue than other illuminators. It should be noted that the daylight blue filter was not created for photomicrography.
When using a filter that is not already mounted, the filter is most often placed over the transmitted light source. Before purchasing a microscope filter you will want to measure the diameter (in mm) of the light source to ensure that the filter will fit on top of it. Some microscopes have a filter holder, and if this is the case, measure the diameter of the microscope filter holder.
