32 mm darkfield filter stop for microscopes

This is a set of darkfield filters measuring 32 mm OD and 4 mm thick. I designed it to fit the swing-out filter holder of a Leitz/Leica HM-LUX compound microscope.

I include micrographs showing fine soil particles suspended in water. The first micrograph
shows the darkfield filter in action, while the second micrograph (with the orange hue) is standard brightfield lighting. Darkfield lighting makes it easier to appreciate the texture and colours of the soil.

You can open the included .f3d file in Fusion 360 to change the dimensions of the filter if you like.