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Trichromatic Image Creation - Prelude

by Uwe Heimburger

I love Black & White photographs and so I convert a lot of my photographic color work to Black & White.

In recent years a stronger interest in digtial cameras using monochrome sensors. Not much choice I'd say. Phase One cameras starting at around 60.000,- € and Leica monochromes step-in price around 5.700,- € for the fixed focal length compact Leica 2 monochrom. For Leica M monochrome I'd have to pay body plus one lens around 12.000,- €. Oops.

Suddenly in spring 2023 Pentax announced the Pentax K-3 Mark III Monochrome body at an affordable price. So Pentax is the third of the party! - Best of all, since tens of years Pentax is my brand of choice. So I would be able to use all of my lenses I already own. The base of the Monochrome camera is the Pentax K-3 Mark III, Pentax' Flagship Model of the APS-C line.

When an extremely good price offer came along, I couldn't resist buying this very specialized camera. With this purchase a new journey began.

I love experimenting and learning. And so I always test what I can do with such new toys. On a member showed a trichromatic image he made. Trichromatic image technique is one where we start with three color filtered black & white captures and end with a color image. This was already done with analog film more than 100 years ago. In the digital age people use an analog-digital hybrid process where they capture three film black & white images using a red, green and blue filter in front of the lens. The film images are digitized using a scanner, and then the three digtial images can be blended using an photo application that supports layers, such as GIMP, Photoshop or Affinity Photo.

Usually the digital cameras of today use a very similar process to create color images. The difference is, the red, green and blue color filters sit on the sensor. In front of each sensor site (cell) exactly one filter and all of these color filters are organized in a fixed grid called the Bayer Pattern.

Each Pixel Color of an bayer-pattern image will be interpolated from four components - one red, two green and one blue. So real color resolution will not be that of the phyical sensor. A raw converting process based on this pattern creates color images inside the camera.

Using the trichromatic approach we at least theroretically can use the full resolution of the physical sensor, ~25% more than using the bayer-patterned one.

With Trichromatic Photography we can explore the roots of color photography. And I was ready to do this based on a completely digital basis. The gif animation below shows images I captured of a Color Calibration Card which at the end of my process resulted in a color image.

In following posts I'll tell the story about my journey in Trichromatic Photography, especially how I got accurate color. I'll do this in a kind of workshop style. So you may be able to adapt it to your tools, if you like to.

Hope you enjoy - have fun!

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