Question on raster brush hardness

[Nyanko]

I am trying to understand how hardness works on raster brushes but I don't see any difference with strokes whether the brush is 0% hardness or 100% hardness. I only see it on the erase tool, one looking softer than the other. Is it supposed to work that way? Thanks. 

[gdenby]

Hi, Nyanko,

What I know about brushes only comes from using them, and messing around a bit making my own. I suspect the hardness setting changes the amount of contrast in the grey scale range. In bushes that are built from a dab that has a broader grey scale, hardness compresses that range, till the dab is all but black. See the attached example. Each set of strokes goes from 0 - 100 hardness , increment of 25. The 1st in the upper left is a good example using a basic brush included with Photo, Some others are also included, but have only an irregular shape w/o much grey. There are a few samples from Frankentoon and Daub that show a difference between hardness settings, more or less as the brush was designed.

Note also, that changing the flow parameter can also have an impact on the relative strength of the stroke. In other words, low hardness + high flow approximates high hardness + lower flow.