Today I’ve been experimenting with #trichrome, 26 November 2022

I’ve had some red, green and blue filters knocking around for ages, but never got around to using them. Today I thought I would try some digital trichromes with the Nikon Coolpix 990, a 3MP digital camera from the year 2000.

First of all I set the camera to the ‘Rec M’ setting which remembered my previous settings of black and white and manual mode that I had used for testing the infrared capability of the Coolpix 990. As I had found that making infrared exposures were better with ‘program’, I set the mode to program.

I then took three photographs, using the red, green and blue filters, and uploaded these to a pen drive. The images were processed with GIMP photo editor adapted slightly from the method outlined by Joshua Bird in his article, Recreating Aerochrome – A Discontinued Infrared Film.

Joshua Bird’s method was devised for infrared photography as he was trying to recreate the aerochrome look, but here I was interested in producing a conventional trichrome. In GIMP, the three images were copied as layers into a single image file as red/green/blue (top/middle/bottom).

In the red layer the green and blue channels were set to zero, in the green layer the red and blue channels were set to zero, and in the blue layer the green and red channels were set to zero. The blending mode of the red and green layers was set to ‘addition’, and that was it.

The procedure for making a trichrome image from three black and white images.

All that remained was to zoom into the image and move the layers around, if necessary, so they were completely aligned, and then save the files as GIMP .xcf files for later. Finally, the layers flattened and the images exported as PNG or JPG files.

In Joshua Bird’s method he used a 720nm Infrared filter, a normal red filter and a green filter for the red, green and blue channels, respectively to recreate the original aerochrome look. I did actually take an image with the IR filter, so I thought I would try Joshua’s method with the Coolpix 990 images. I was delighted to discover that it worked very well!

The procedure for making an infrared trichrome image from three black and white images.

Of course, while I was in the mood I felt that had to try some trichromes with the Sony Mavica MVC-FD81 floppy disk camera. I’m planning to use this for the upcoming #ShittyCameraChallenge #1990sCameraChallenge. In this case, although the image was a little dark and muddy, and will probably need some adjustment for the final result, I was very happy with the result.


Published by Keith Devereux

'Let me close my eyes and sense the beauty around me. And take that breath under the dark sky full of stars.' Mira Furlan

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