Making the most of Kodak aerochrome

Kodak Aerochrome was designed for use in aerial photography, with forestry, cartography, industrial and military applications.

Writer and photography / “lazybuddha” on Lomography

---

Had it not been for the amazing response to my albums, I would never have considered writing this article because I am still a Lomography novice. There are many others much better than me and with much more Aerochrome experience. I sought advice from some of these great Lomographers before experimenting with Aerochrome and they were all very willing to share their knowledge. So,in that spirit, here is the little I have learned so far.

First off some background on the Kodak Aerochrome

Kodak Aerochrome was designed for use in aerial photography, with forestry, cartography, industrial and military applications. Therefore it only comes in sizes designed for aerial cameras, typically 9.5 inch by 400 foot rolls. These tend to be a little tricky to fit into your standard 35mm or 120mm camera. So the fact that you can now find this film in 120 format (and very rarely in 35mm) means that someone has cut it down in complete darkness and re-rolled it, which is not easy. Coupled with the fact that it is now discontinued, means that it is expensive and extremely rare. All the more reason to perhaps ignore one or two of the 10 Golden Rules and put a little more thought into using it so as to make the most out of it.

Filters explained

Aerochrome is sensitive to the entire visible spectrum of light in the same way as normal film, the only difference is that its sensitivity is extended beyond 730nm (wavelengths of light are measured in nano meters) into the invisible near infrared. In fact, Aerochrome and other infrared films are actually more sensitive to blue light than normal film and that is why if you want to achieve true IR effects, a filter is so important. If you use Aerochrome without a filter, you will still get the intense contrast and textures but without the IR effects. Most people recommend either a yellow or orange filter but you can also use a red or even a green filter. In general, the darker the filter, the darker the reds and sky, and the greater the contrast. The lighter the filter, the pinker the reds and greener the sky. Here are some examples of the different effects from different filters.

Red filter with Kodak Aerochrome

Orange filter

Yellow filter

Green filter

Note: Many other factors will also have an effect on your image beside the filter.

Exposure of the aerochrome film

Aerochrome is rated at 400ISO for use with a yellow filter, which means if you use a yellow filter then you meter at 400ISO. However, Aerochrome is designed to be processed in AR-5 chemicals with E-6 the nearest easily available alternative. If you want to cross-process in C-41 then it’s ISO rating changes to around 320. All my shots so far have been cross-processed in C-41 and as I never use a light meter my general guide for bright sunshine is;
Yellow filter – f22 1/125 sec
Orange filter – f16 1/125 sec
Red filter – f11 1/125 sec

If you overexpose a little, you lose the color in the sky but gain more detail in the textures. If you overexpose a lot, the images become very bleached out. Here are some samples: The first is slightly underexposed and the second is slightly overexposed.

Processing the photograph

As Aerochrome is designed to be processed in AR-5, it does not behave in the same way as other slide films. Normally, cross-processing side film results in extreme saturation and strong contrast, but with Aerochrome processing in E-6, it produces the most saturated images. Cross-processing in C-41 actually provides more detail. As Aerochrome images tend to be heavily saturated anyway, I find the increased detail of cross-processing to be an advantage. For a more detailed analysis and comparison of E-6 versus C-41 processing see here

Light source

The colour we (or the camera) see is dependent on two things, the color that the object absorbs/reflects and the light source. To perceive the true colour of an object, the color must be contained in the light source in order to be reflected. In the same way to capture the IR properties of an object, the light source must contain IR light. Sunlight is the best source of IR light but tungsten halogen lamps also emit IR. Most other artificial lighting (fluorescent and sodium) only emits visible light and so will not give you any IR effect. In fact many modern artificial lights are designed to emit as limited a range as possible for energy saving reasons. For this reason Aerochrome should not be used indoors or under artificial lighting except tungsten halogen.

Foliage

All different kinds of plants, including different types of trees and grass reflect IR light to slightly different degree. Therefore, they will all be slightly different shades of red in the final image. The lighter the filter, the more these differences will be obvious. A light yellow filter for example will give you many more shades of pink and red than a red one because obviously the red filter will block the lighter pinks.

Focusing

When light passes through any piece of glass, it bends (refracts) and because different colors have different wavelengths, they refract to different degrees. Normal camera lenses are ground and coated to focus all visible wavelengths (but not Infrared) onto the same point—the film. Therefore, having a longer wavelength, IR light focuses behind the film. Adjusting for this is tricky as obviously we are dealing with what we can’t see. Some old lenses have a red dot on them that is designed to show the adjustment needed for IR. If you are not lucky enough to have one, my rule of thumb has been to focus 1/3 to 1/4 closer than the visible focal point but it is largely trial and error. Obviously, the smaller the aperture you use the better your chance of success as it will increase your depth of field. Focusing accurately with a large aperture, such as f2.8, is extremely difficult.

Other factors that have a bearing on your final image are such random things such as atmospheric conditions and even height above sea level. With IR film, it really is a case of experimenting and seeing what works. But with a little homework before hand, hopefully we can keep the disappointments to a minimum. Good luck!

This article is originally from the Lomography series.