In a few previous projects, I investigated ways to create images that look like the famous Kodak Aerochrome infrared film. As a film stock that is just not available anymore, we must look for ways to re-create it in creative ways. The color swap method gets easily confused on things that are green but not plants and the digital full spectrum method requires complex and often permanent modifications to expensive cameras. But where is our film option?
Thankfully there is still infrared-sensitive film in production but it’s black and white only. How can we use this to create a color image? It’s actually pretty simple and uses a photographic method that predates color film, it’s called trichrome photography! This is where three images are taken of the same subject with various color filters, then those filters are overlayed on top of each other to create a color image.
PetaPixel: A Brief History of Color Photography
But instead of using 3 color filters use 2 color filters with an IR cut filter and one infrared-only filter to render the infrared light in its own layer. The basic setup is detailed in this wonderful post on Hackaday.
So I went and tested the theory with my digital full spectrum camera with various filters and combined them into one image to see if I could make this work. This method needs to have the camera in the same position for the three shots so it’s necessary to have it on a tripod. Here are the three images Infrared (red), blue, and green.
Assign them the correct colors for a trichrome color image.
I then used Affinity photo on my iPad to align the images into a stack and combine them with a Total blend mode to create the final Aerochrome-looking image below.
This process works but you end up with trichrome artifacts that give moving objects a rainbow-like appearance since all three images were taken in sequence instead of all at once.
So how do we do this with a film camera, well we could cart a tripod around and methodically take three images, or we could take all three images at once!
Handheld Infrared Trichrome
There are only a few cameras with more than 2 lenses, this is because they are really only useful for making moving 3D images or “wiggle grams”.
Here is an example gif of the 3D-like “Wiggle grams” image the cameras are designed to create.
Thankfully there is a cheapish camera that recently came out called the Reto3D. It’s an adaptation of the reusable disposable film camera trend. where a cheap plastic lens, body, and mechanism are taken from a disposable camera and modified to be reloadable.
The Reto 3D camera takes three half-frame images on 35mm film, this is perfect for the trichrome infrared project. Now I just need to make a custom filter to mount onto the front shouldn’t be too difficult right?
The 36mm IR cut filter and the 52mm 720nm IR filter kinda fit but my 52mm color filters used to separate the green and blue parts of the image are too large and will overlap.
So I need to either find smaller filters or cut these to size. Thankfully I came up with an ingenious solution, plastic bingo chips!
These are cheap replacements for the color filters I used in the digital camera experiment. They are unfortunately not of high optical quality…
but the hope is that they are close enough that the edges don’t matter and only the center is required for clarity. So I dug through the whole lot and found the best examples just in case!
There is unfortunately no cheap small replacement for the IR cut filter and the 720nm infrared filter. Thankfully they fit somehow!
I then designed this 3D filter holder in OnShape to correctly space the filters and serve as a way to mount them to the camera.
Using some gloves to add the filters to the 3D print and some 3m mounting tape to hold the contraption onto the camera, we now have our hand-held trichrome infrared camera. Now for testing!
Tri-Aerochrome Images
using the Reto 3D camera with custom lens filters to snap all 3 images at once I was able to get approximately 24 images on a 36 roll of 35mm film. This is because it takes 3 half-frame images at once, so the images don’t have a ton of quality.
Ilford SFX 200 film straight from the lab, we get 3 black and white half-frame images
we then apply the correct color to each image. red for the infrared channel, blue, and green respectively.
Combining them in a stack in affinity with an alignment transform layer allows us to correct the parallax between lenses.
crop the image to the usable portion and there we have it! our first film Tri-Aerochrome image. It’s a bit grainy and low resolution but I’m surprised at how well this works!
Gallery
Here is a gallery of the others, not every image turned out. I believe this is due to the film only being at 200 speed. I am going to try 400-speed rollie IR in the future and possibly push it a stop or 2 to correct for the cameras lacking manual controls.
The overall image quality is probably the least attractive thing about this solution. Given the smaller negative, plastic lenses, and imperfect color filters this is to be expected but it’s the easiest film color infrared camera out there to use to date!
Build Your Own
You can buy most of the parts from Amazon and you can usually buy the film from there as well.
- SVBONY Telescope Filter, 36mm Unmounted UV IR Cut Filter
- GREEN.L 52mm Infrared Filter, Multi-Resistant Nano Coating HD 52mm X-Ray IR 720nm Filter
- RETO Reto3D 35mm 3D Film Camera – Retro Lenticular 3D Effect Boomerang Wigglegram Camera
- SFX 200 35MM
- Learning Resources Transparent Color Counting Chips – 250 Pieces, Ages 5+ Math Counters for Kids, Counting Chips, Perfect for Bingo Games
You will then need access to a 3D printer to create the filter mount. I have uploaded the design on printables for you to download for free.
Printables: Tri-aero Aerochrome Reto3D Filter
Install 2 red bingo chips in one of the holes that are inside the smaller cutout for the 36mm IR Cut filter and install one green chip and one yellow chip in the other. Then install the IR Cut on top. You can then install the 52mm 720nm Filter into the larger cutout. You may need to add some sticky tape as needed to keep the infrared filter in place. Do not force the 720nm filter it is very brittle and can crack if you apply too much pressure. File down the cutout if it does not slide in easily. Once that’s done add a copious amount of 3m mounting tape to any of the flat surfaces in order to attach the filter holder onto the camera. Just make sure not to block any of the filters. Then place the filter with the larger cutout on the side of the camera with the flash and align all the lenses. Then use a large book or ream of paper as a weight to apply pressure to the mounting tape in order to secure it.
Want to Shoot Film on your iPhone?
If you liked this post and want to try shooting some Aerochrome-like film on your iPhone consider purchasing my 36Exp film camera app now available on the iOS App Store!
Reto-Aerochrome V2 Update!
YouTube Videos Featuring the Reto-Aerochrome Filter
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