This plug-in lets you posterize images in any given number of luminance levels or color tones. Create equidistant scales.This is the Posterizer plug-in’s control panel. Click on the image for a larger view.It works with the following image modes:8 & 16 bit/channel: RGB, CMYK, Grayscale, Duotone, Lab.
Divisions lets you set how many value divisions the image should be divided into.
Here is an example of five equidistant value divisions created with the plug-in.
Normally three value divisions is the most aesthetically pleasing as arthistory has proven to us, but five is also often used. Usually odd numbers are preferred so you get a midtone. Arthistory has shown that 2,3 and 5 are the most useful.More than five becomes difficult to distinguish. At about 70 the eye can no longer distinguish between them and perceives a gradient as a smooth one.
Force black will make the darkest pixels as dark as possible.Force white will make the brightest pixels as bright as possible.The value divisions are then calculated from that range.Greyscale will output a colorless result.Colorize grey will assign equidistant colors to the given greys. The colors will approximate the given colors in the image.
Divisions lets you set how many distinct hues the image should be divided into.
In the examples to the right we have divided a snap of a regular colorpicker into three distinct hues.Selection shift lets you change the basic hues to be selected throughout a full color circle, as you can see in the example.Brightness levels was set to 1.
Amount determines how much the changed image will be mixed with the original image. 100% means nothing is left of the original.Mode will set various modes of combining the original with the edited image. We have Normal + 12 modes, most of which are well known from Photoshop.Hue change, unlike Selection shift, will preserve the given selection of hues, but will rotate their colors throughout the color circle.
In this example we turned off brightness divisions by setting the Divisions slider to 0. Here is the output with Normal blending.Brightness divisions = 0Hue divisions = 1Selection shift 90 (to turn from yellowish to soft orange)Output amount = 70%
Greyscale & Colorize Grey
By converting the image to greyscale and colorizing the levels, you get exact control over the number of distinct levels and hues in the image, since the will occupy the same space.