The new sigmoid module in darktable 4.2 makes it easy to create dramatic black and white compositions. While there are many ways to achieve this effect in darktable, sigmoid makes it fast and easy. The general steps to create dramatic black and white images are:

  • exposure - set a proper exposure for the image
  • sigmoid - increase the contrast slider quite a bit, to around 2.0 or greater; also ensure filmic rgb is turned off
  • color calibration - on the gray tab, increase the sliders to create a black and white image from the RGB channels, balancing how much you use of each channel to achieve the desired effect
  • tone equalizer (optional) - if needed, use tone equalizer to make adjustments to the shadows or highlights to further enhance the contrast; for example:

Some additional examples:

See below for a demonstration of how each module contributes to the overall look: