Grayscale Image Creation (Not Converting)

[cli345]

Yes, I started with the color image.
I made it this way:

• Duplicate Layer
  
• On lower layer
  • Convert image : Image -> Precision -> 32 bits integer
    
  • G'MIC -> Repair -> Smooth [NL-means]
    
  • New Layer filled with yellow (255,255,0), mode "multiply", merge down
    
  • Colors -> Desaturate -> Color to gray
    
  • G'MIC -> Repair -> Smooth [NL-means]
    
  • Colors -> Curves : add point (224, 128) and point (64, 0)
    
  • G'MIC -> Details -> Local Contrast Enhancement (amount=0.1)
    
• On upper layer
  • Filters -> Artistic -> Comic Book for 2.10
    
  • G'MIC -> Colors -> Curves (Colorspace=Lch) : lower Chroma to 0 everywhere, add a point (32,255) on Lightness
    
  • set opacity to 75%
    
  • set mode to "multiply"
    
• merge down
  
• Reduce by 50%