Comment 4 for bug 186432

The files \Inkscape\share\extensions\color_custom.py and *.inx have been modified to allow for two types of input color range for (r,g,b) : 0-1 (which is the default) and 0-255 (which is new). New versions of these files are attached.

The files have been tested with the above values for the 0-255 range and with the following values for the 0-1 range :
Red Function = (r+g)/2
Red Function = r + 11.0/255
Red Function = 59.0/255

It appears to behave appropriately in these cases.