Visible Spectrum vs. Infrared

Re-enactment photographer capturing a wet plate photo of the Confederate Widow.

While working on the update to my website I started reviewing the photos I want to publish for my 150th Anniversary Civil War project. During this process, I was reminded of the significant difference in what the camera sensor captures in a normal light compared to infrared.

Shown below are examples of these differences. The photo on the left shows the Confederate Widow in her black satin mourning dress. The photo on the right only captures the infrared spectrum of the same dress. Dark fabrics reflect IR light in varying degrees based on their texture and material, often appearing lighter than expected in photos. This can lead to surprising results where black clothing might appear gray or even white.

Confederate Widow (B&W)

Confederate Widow (Infrared)

The infrared spectrum is outside the range of light that our eyes can perceive. We can see light in the wavelength range of 400 to 700 nanometers. Infrared light is a spectrum that begins at around 800 nm and goes to 1,000,000 nm. Our eyes cannot pick up these longer wavelengths but my converted digital camera sensor can expose these images.

Union Soldier loading his rifle

Union Soldier loading his rifle (infrared)

While working on this project it was often difficult to tell the differences between Union and Confederate soldiers since everyone was in a shade of grey. Union soldiers wore dark blue uniforms, Confederates usually wore grey or butternut, but with more variations than northerners because the individual southern states often provided uniforms. The easy way to tell the difference is the Union soldiers generally wore what was known as a kepi, a French term, which was a fabric hat with a round, flat top and a leather visor.