1. You have a color picture like this

2. You want to print the image with a laser printer or any ohter printer in black and white. Or you want to create a special effect with a black and whit image.
PL32 offers many raster types to convert a color image to black and white.
Rasters are small rectangles, here a black points which correspont to the color (intensity) of the color image by the size of the points or the amount of points.
You can setup the raster at Layer/Convert Layer Type.

3. Here are some examples for rasters in PhotoLine

Bayer Dither	Coarse Fatting	Vertikal Line
Fine Fatting	Ordered Dither	Dither 45 Grad
Floyd Steinberg

4. Be aware that rastered images should normally not be scaled when you print them. To avoid this, first setup the resolution of your printer at Layer/Layer Properties. Then scale the image to the size you want at Layer/Scale Layer. Here you can setup the size of the image in mm.