Colour reduction with pencil drawing
Color reduction using the Pencil Drawing filter is used when you have detailed images. This filter tries to locate and highlight the figures that make up the image. The figures shall have sufficient contrast and shall not be too small.
The pencil drawing detects the edges, regardless of the color of the figures that make up the images. Even on dark or black surfaces, only the edges will be highlighted. Refer to the Pen Drawing filter for a filling effect on dark surfaces.
This filter has some parameters:
- Contrast: Contrast value between adjacent colors to identify edges to highlight. Low contrast detects the subtlest variations, while high contrast detects the most pronounced variations;
- Surface: The width of adjacent surfaces for edge detection. With small surfaces more detail is detected, less with larger surfaces;
- Distance: the distance between adjacent surfaces. Small values identify colour differences between neighbouring surfaces, while a larger distance between distant surfaces.