Hope these screenshots will explain Binuscan Photoretouch Pro 8 grayscale conversion methods

These JPEG images are tagged with sRGB profile for web viewing.

This is the original RGB (I did run Auto Process RECO on it):

The Grayscale Conversion screen:

Green (RGB) method

Intensity method

Lightness/Destaurate (HSL) method

Median method

Luma (Ycc) method

Luminance (Lab) method

Adaptive Luminosity method

Classic (bCP) method

Which one you prefer?

Anyway, those interested in PhotoRetouch Pro, a demo can be downloaded from here.

P.S. Sorry it's available on Mac only for now.