Polarized light capability can be added to one of those affordable USB microscopes which are becoming so widely use for art examination. I posted already on the usefulness of those  hand held microscopes, such as for documentation of pigments size and mixtures, craquelure features, textiles, observation of the preparation/ground through the cracks. I introduced the concept of Polarized light when talking about better quality photography of paintings, by reducing annoying glare and I showed how polarized light is widely use in microscopy for identification of pigments. 

This post gives some hints so you can make your bare USB microscope a Polarized USB microscope for transmitted polarized light observations. The next post will show a specific application where this piece of equipment turns helpful.

I adapted the 5MP USB microscope described here. Other accessories: a photographic LINEAR polarizing filter, a flash diffuser and a strip of polarizing plastic sheet. I used my stereomicroscope and an IKEA lamp but you can find out the solutions that better suits you.  This is the video to show how to make this polarized USB microscope and how it works.

Some observation of prepared slides with historical pigments, azurite and synthetic ultramarine. The polarizing system works; in crossed polars light azurite (anisotropic) looks bright while synthetic ultramarine (isotropic) it’s totally dark.


Azurite is anisotropic and turns bright in crossed polars.


Synthetic ultramarine (French ultramarine) appears totally dark in crossed polars.