Reset image
Grayscale
[0.2125, 0.7154, 0.0721]
Manipulate channels
([r, g, b]) => [1/4 * r + 127, g, b * 0.9]
Reset+grayscale+binarise
Binarise current image
Group colours
[1, 2, 1]
Convolve, preserve edges
Convolve, update edges
Kernel.unsharpen