The ERODE and DILATE Filters

ERODE left - Dilate centre - Origunal right. The filter has been applied 10 times in this example.

There is very little information on the ERODE and DILATE filters and the Processing Reference, suggests these modes are used along with parameters. The filter method however accepts no parameters with these modes.
When one of these filters is applied to an image, there seems to be very little difference. There is a slight difference when the stroke weight is small.
By repeatedly applying the filters to an image however, the effect becomes more noticeable.
ERODE lessens the presence of light areas and DILATE increases them.