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
Lightness/Destaurate (HSL) 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.