PAINTING ON LOCATION FINE ART GALLERY 5

  How do you make a dark nutral color, one that will make a neutral gray tint?

  There are eighteen ways, here are the three primary ways.  
#1. Magenta (Thalo Magenta W/C, Acra Crimson Acrylic), and Thalo Green.  
#2. Burnt Umber and Ultramarine Blue. 
#3. Cadmium Red and Thalo Blue. 
YOU DON'T NEED BLACK PIGMENT!!!

What color does Yellow darken into?  Brown.   
Like the iron crystal GOETHITE, a iron hydroxide crystal found yellow to brown in earthy masses, it's an ore of iron that contains the natural yellow ferric oxide pigments. 
LIMONITE is a secondary ore of iron that forms yellow to brown oxides. This is  proof for my color theory and color wheel.  All 36 colors in my Real Color Wheel are matched to dark in this crystal matching way.