Re-Creating The Unique Look Of Unobtainable Aerochrome Film

August 1, 2022 by Donald Papp 23 Comments

Ever heard of Aerochrome? It’s a unique type of color infrared film, originally created for the US military and designed for surveillance planes. Photos taken with Aerochrome film show trees and other vegetation in vivid reds and pinks, creating images that aren’t quite like anything else.

A modified method of trichrome photography is the key behind re-creating that unique Aerochrome look. Click to enlarge.

Sadly, Aerochrome hasn’t been made for over a decade. What’s an enterprising hacker with a fascination for this unobtainable film to do? [Joshua] resolved to recreate it as best he could, and the results look great!

Aerochrome isn’t quite the same as normal film. It is sensitive to infrared, and photos taken with it yield a kind of false color image that presents infrared as red, visible reds as greens, and greens are shown as blue. The result is a vaguely dreamy looking photo like the one you see in the header image, above. Healthy vegetation is vividly highlighted, and everything else? Well, it actually comes out pretty normal-looking, all things considered.

Why does this happen? It’s because healthy, leafy green plants strongly absorb visible light for photosynthesis, while also strongly reflecting near-infrared. This is the same principle behind the normalized difference vegetation index (NDVI), a method used since the 70s to measure live green vegetation, often from satellite imagery.

Aerochrome may be out of production, but black and white infrared film is still available. [Joshua] found that he could re-create the effect of Aerochrome with an adaptation of trichrome photography: the process of taking three identical black and white photos, each using a different color filter. When combined, the three photos (acting as three separate color channels) produce a color image.

To reproduce Aerochrome, [Joshua] takes three monochromatic photos with his infrared film, each with a different color filter chosen to match the spectral sensitivities of the original product. The result is a pretty striking reproduction of Aerochrome!

But this method does have some shortcomings. [Joshua] found it annoying to fiddle with filters between trying to take three identical photos, and the film and filters aren’t really an exact match for the spectral sensitivities of original Aerochrome. He also found it difficult to nail the right exposure; since most light meters are measuring visible light and not infrared, the exposure settings were way off. But the results look pretty authentic, so he’s counting it as a success.

We loved [Joshua]’s DIY wigglecam, and we’re delighted to see the work he put into re-creating an authentic Aerochrome. Fantastic work.

The Coming Wide-Spread Use Of Drones In Agriculture

May 9, 2016 by Donald Papp 39 Comments

Whether you call them UAVs (Unmanned Aerial Vehicles), UAS (Unmanned Aerial System), Drones, or something less polite – people are more familiar than ever with them. We’ll call them drones, and we’re not talking about the remote-controlled toy kind – we’re talking about the flying robot kind. They have sensors (GPS and more), can be given a Flight Plan (instructions on where to go), and can follow that plan autonomously while carrying out other instructions – no human pilot required. Many high-end tractors are already in service with this kind of automation and we’ve even seen automated harvesting assistance. But flying drones are small and they don’t plant seeds or pull weeds, so what exactly do they have to do with agriculture?

There are certain things that drones are very good at, and there are things in agriculture that are important but troublesome to do or get. Some of these things overlap, and in those spaces is where a budding industry has arisen.

Continue reading “The Coming Wide-Spread Use Of Drones In Agriculture” →

Seeing Plant Health In Infrared

July 3, 2013 by Brian Benchoff 13 Comments

aerial

Since the 70s, NASA, NOAA, and the USGS have been operating a series of satellites designed to look at vegetation health around the world. These satellites, going under the name Landsat, use specialized camera filters that look at light reflecting off chlorophyll to gauge the health of forests, plains, oceans, and even farms. It’s all very interesting technology, and a few very cool people want to put one of these near infrared cameras in the hands of everyone.

The basic idea behind gauging the health of plants from orbit, or the Normalized Difference Vegetation Index, is actually pretty simple: absorb red and blue light (thus our verdant forests), and reflect nearly all infrared light. By removing the IR filter from a digital camera and adding a ‘superblue’ filter, the NDVI can be calculated with just a little bit of image processing.

The folks behind this have put up a Kickstarter with rewards including a modified webcam, a custom point and shoot camera, and a very low-cost source of one of these superblue filters. Just the thing to see how your garden grows or how efficiently you can kill a houseplant.