Five ways to replace tone with the density of small marks, the way etchings and newspaper photographs do.
Pointillize is the odd one out and the most literal. Points are scattered across the picture, each reads the colour beneath it, and draws a dot that grows larger as that colour gets darker. The dots keep the original colours, so it reads as a painting rather than a print.
The three mezzotint modes compare each colour channel against a field of noise. The dot version uses even noise. The line versions use noise that is stretched: coarse in one direction and fine in the other, so it holds together down a column while changing rapidly across a row. That produces streaks directly, without any blurring or smearing step.
Reticulation varies the noise by brightness, so shadows fill with broad clumps and highlights break into fine grain, imitating cracked photographic emulsion.