Color is a strange thing.
Infrared is the light that comes after the spectrum (rainbow) and our eyes can't see. Like any film, IR film is sensitive to normal light but it's also sensitive to infrared radiation found between 700 and 900 nm, and that's why a infrared-passing filter must be used to block as much as possible the visible light spectrum in order to achieve a real IR image. - Aldo Altamirano
Kodak’s color infrared film was first created, or at least majorly intentioned, for military and geological research purposes. The US Air Forces commissioned color infrared film from Kodak in 1942, in order to distinguish green camouflage from naturally green foliage during World War II.
Normal colour films have three sensitized layers that react to the three primary spectral regions: blue, green and red. When the film is developed, each layer produces a dye of a complementary colour: yellow, magenta, and cyan, respectively. When visible light passes through the three dyes, a reproduction of the colour in the original scene is formed. This makes for a positive image on the transparent film base. With a negative-type colour film the colours of dyes will be complementary to the colours in the original scene. Green hues turn to purple or blue, depending on the hue of green. Yellow and orange hues turn pink. Reds stay red, or convert to a brownish red. Blue hues turn to cyan and aqua hues. – Saskia Boer
Infrared color films like Kodak’s Aerochrome using a false coloring technology to assign color to ranges of infrared light that the film can detect but our eyes cannot. These films also classically turn greens into hues of purple. This false coloring scheme was originally geared toward military purposes – to distinguish real greens from camouflage greens in the field – and geology purposes – to more easily visualize different types of foliage, etc.
When the colour of the dye formed in a particular layer bears no relationship to the colour of light to which the layer is sensitive (if the relationship is not complementary) the resulting colours are false. The dyes assigned to certain colours are thus arbitrary. False-colour films can be used to emphasize differences between objects that are visually quite similar. If one needs to be able to recognise infrared light, the infrared must be represented by another colour, since the human eye cannot see it. Infrared photography is thus a means to make the invisible visible. […] Infrared radiation, which bounces off the chlorophyll in green plants, appears as red, which is the result of the subtractive colour mixing of the yellow dye in one layer and the magenta dye in the other layer, and the absence of cyan. – Saskia Boer
But despite the technical functions for which color infrared film was originally created, this film was quickly popularized in the 1960s. Famous musicians including Jimi Hendrix, Donovan and Frank Zappa used the film to create trippy-looking album covers.
Kodak’s color infrared film was discontinued a few years ago, around 2009, due to the rise of digital photography and decreased military demand for the film. But Richard Mosse picked up what was left for his haunting photography project to reveal the “unseen” aspects of conflict in the Congo.
Fast-forward a few years, and the look of color infrared film seems to be coming back in niche markets. Just over a year ago now, the online shop Lomography introduced Lomochrome Purple. This film mimics Kodak’s color infrared film without truly being infrared-sensitive in the same way that the original film was. Lomochrome Purple is convenient in that it can be processed using standard C-41 chemistry – in other words, you can take it to your local photography lab or Walgreens for processing.
LomoChrome isn't sensitive to infrared, but instead produces its unique look through a chemical formulation that causes severe color shift in images and a dark green film base that really pushes the purple. – PC Mag
Lomochrome Purple converts green hues into purple and blue hues, depending on the hue of green. Reds become light purples and reddish browns, while blues become cyans. Light reds and pinks may become yellows or oranges.
I loaded a roll of 35mm Lomochrome Purple into my vintage Olympus OM-2 recently, and walked around my neighborhood in downtown Baton Rouge. I also went to the Mississippi River Bridge in Baton Rouge, having the idea to shoot the grassy levee and trees framing the bridge. I’m loving the results!
I got the best results when shooting in open sunlight - when processed using C-41, the images came out naturally with a ton of contrast.
Shots of flowers come out fantastically on Lomochrome Purple - they seem to be transposed into an alien environment, and yet are still universally recognizable and beautiful.
A blue sky is converted to a strange and striking expanse of cyan. This crepe myrtle and bird on a telephone wire is not so commonplace on Lomochrome Purple.
But bright green foliage brings out the best in Lomochrome Purple.
Have a 35mm camera? Grab a role of Lomochrome Purple and share your pics with me on Twitter or Instagram @fromthelabbench!
For more on how to get the hues of purple you want out of Lomochrome Purple, see this post by a photographer writing at Lomography Magazine