When some people learn that the beautiful images from the Hubble Space Telescope are really several monochrome images taken with different filters, coloured and then combined (see Hubble’s Behind the Pictures to learn more), they cry foul. When I learned this I wanted to take my camera and turn it into a mini-Hubble and explore the world around me.
The first thing I had to do was get my hands on some colour filters. A quick eBay hunt put me on the path of some lovely square colour filters and a mount for my camera. I even lucked out and found a second hand IR, or near-infrared, filter at a reasonable price.
When my filters arrived the other day I grabbed my camera, my tripod and the first houseplant that came under hand and started taking pictures. I set my camera to monochrome and put in the red filter. It took a little bit of playing around with the settings, but I finally got a half descent black and white image. I’m no whiz at photography, usually leaving my camera on full auto, but I like to think I did okay for my first time shooting in black and white and using a filter.
After I had my first image, I took pictures with my green and bleu filters. Finally came the time to try the IR filter. I had done some reading and so I knew that because the filter blocks all visible light and only lets in the near-infrared light, I needed a longer exposure. I had also read that plants are great reflectors of IR light.
Unfortunately I couldn’t get an image, even with a thirty second exposure. Then the light dawned on me, I was shooting under a compact fluorescent bulb, which means little or no heat and likely little or no light in the IR spectrum. Thankfully I have a bed lamp that still has an incandescent bulb in it. I removed the shade, set up the light and took all my pictures again, red, green blue and IR. They all worked!
I imported the images into an image editing software (I use Gimp) and then coloured each of the individual images.
I then had to align the images, as it appears even my best attempts to not move the camera while changing filters were marred by my excitement. Finally I overlay the red, green and blue images and got a lovely colour photo.
For fun, I swapped out the red image for the IR image and got a ghostly almost Marian looking plant. I can’t wait to try out new locations and techniques as I explore the world through Hubble’s eyes.