Threshold, Desaturate and Posterize
Among the options of the Colours Menu, we have 3 important Functions: Threshold, Desaturate and Posterize.
We can say that these 3 functions have been inherited from the common practice in photography before computers turned photography labs into a thing of the past.
In past times, the processes to achieve special effects were based in techniques which in some cases required the use of chemical formulas or special paper to achieve the results we can now get with these functions.
In honour of that practice, we dedicate this lesson to show you what a photographer or a photographic lab were able to achieve with only a dark room.
Threshold: This technique was achieved by using special types of paper and developing processes. In this case, by moving the small triangle or the value, we obtain different results upon the bright or dark areas of the picture.
Desaturate: it is nothing more than the black and white technique. By using special types of film and photographic paper and a dark room with a red light, photographers achieved special photographs, movies and documentaries.
Posterize: This technique was widely applied for Poster or Banner design (also used in comics and pop art). We can get different results in Gimp by moving the scroll button.
