Images with solid areas of colour in the main appear artificially smooth. Such areas can result if one works with a colour tool without adding noise, or if one works with vector shapes. With the "noise" tool, such even areas can be "roughened" to a greater or lesser extent depending on the tool parameter settings.
There is a choice of three different methods for adding noise.
The normal mode "Colour noise" ensures that the overall chromaticity of the picture is retained; black areas remain black and white areas remain white.
With the Effect noise button you have the possibility to switch on a mode in which both black and white areas also exhibit a structure; this may give slightly false values to all the colours.
With the two methods discussed so far, individual pixels change their chromaticity. With "Colour noise" the colour is balanced out in the statistical centre of an area, ensuring that the overall colour impression is retained. With "Intensity noise" individual pixels of the image retain their colour, and only the brightness of the pixels is changed. Here too black or 100% areas remain unchanged.
The various adjustments available opens a multitude of uses for the Noise tool.
Note: Unlike the other tools, there is no adjustment for "noise" in the general tool settings dialog for this tool.
Extreme values for intensity increase the unavoidable calculation errors, which in turn can lead to colour or brightness errors in the picture.
