I was quite surprised that my idea of using a 3D film camera with infrared film and a custom filter worked so well in creating an Aerochrome-like image. The basis of the idea can be found in my previous post below.
But there were still problems I wanted to solve, the first being the optical quality of the color filters. Since I was using cheap plastic bingo chips that were not designed for optical imaging I could only really hope for ok center sharpness with edge clarity nonexistent!
So I researched several ways of getting better color filters that would be optically clear edge to edge. This proved more difficult than I thought because no one makes camera lens filters with a 16mm diameter. My options were to pay for custom machining or DIY a solution. Of course, I went for the DIY approach!
On AliExpress I was able to locate a supplier of 37mm color filters in the red and green tints that were less than $2 each. This would fit within the 36mm IR cut filter I already had in my old Tri-Aero filter. But how could I overlay them without interfering with the other lenses? I cut them in half! Creating a bicolor 37mm filter! Half red half green, I excluded the yellow filter because it would have increased the optical depth of the filter holder making it impractical.
But how do you cut the new filters? I tried two methods, the first was just to keep scoring the plastic with a box cutter and then snap it. This did not work well leaving chunks missing on the edge. The second method worked much better, I heated up an exacto knife and gently pressed it into the plastic melting it in a straight line.
This hot knife technique created a perfect cut every time but you will want to throw out the blade at the end since it will lose its structural integrity heating up and cooling down multiple times!
I then reworked my original 3D filter design for the camera to accept the cut halves and decided to rework the 720nm IR filter mount as well to allow you to screw in a filter instead of having to remove it from the filter mount.
this new design is much smaller due to the use of a 37mm IR filter but due to the spacing of the lenses the IR-filtered lens may be cut off a bit, so I may need a revision after this to correct it.
Printables: Tri-aero-aerochrome-reto3d-filter-v2
In this improved version I decided to also try a new film, Rollie Infrared 400! I took it out to shoot around Benicia CA.
The process is exactly the same as in the previous post where I use Affinity Photo to align the images, add the color channels, and perform any curve adjustments.
Gallery
