Polarized Light Photography (PL)

Polarized Light Photography (PL)

Polarized light photography (PL) is a useful method for the documentation of works of art and archaeology. PL photography eliminates surface reflections and professional photographers use it for high-quality documentation of varnished art.

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Applications for Art Examination

PL photography eliminates glare in photos, in particular, disturbing reflections from varnish. Light from the lamps can be reflected or diffused from a painting. Reflected light gives glare while diffused light provides colors and texture. When the light is reflected it keeps its polarization while diffused light loses it. So, when polarized light illuminates a painting, the glare is still a polarized beam while diffused light vibrates in any direction.

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Experimental Set up

A classical experiment with polarized light is that done with a calcite crystal and a polarizing filter.

For manual focus, it can be used a linear polarizing filter. A circular polarizing filter is necessary for autofocus. Indeed, the camera focusing system doesn’t work properly with polarized light. The circular polarizing filter resolves this problem. It is essentially a linear polarizing filter that diffuses the polarized light just before feeding it to the camera. A video on the linear polarizing filter and the circular polarizing filter:

Polarized Light Photography Kit – Pitty