Yellow Green is an opaque color,
Sap Green permanent is basically the same color transparent
but lower on the chroma scale because it has some black or dark red oxide added.
Mix it with it's opposite color transparent Dioxazine
Purple for a neutral dark.
It takes two transparent oppositions to mix neutral or one transparent
and one translucent color,
or two translucent colors, or one transparent and one opaque. Two
opaque colors just won't do it.
Top-tone is adding White to the color.
Under-tone is adding clear.
Mass-tone is thick out of the tube.
Transparent is clear like colored glass.
Translucent is floating colloidal compounds of colored elements.
Milk is translucent.
Opaque is dense and light blocking, like a rock.
YYYY = As Yellow as you can get,
YYYC = Yellow Green
YYMM = Yellow and Magenta, as Red as you can get.
MMMM = pure Magenta
MMMC = Purple
CCCC = Thalo Cyan Blue
These are the Yellow Green to Purple opposition pigments that make a dark neutral color
PY83 stable di-arylide + PG7 chlorinated
copper phthalocyanine = Sap Green Y/S
PY83 stable di-arylide HR + PG7 chlorinated copper phthalocyanine + PO43 perinone orange = Sap Green O/S
PY129 methin copper complex = Green Gold
PY?.. azomethine = Genuine Green Gold
PY129 methin copper complex = Golden Green, Indian Yellow Green
36. CYYY, Old Holland Yellow-Green Organic Opaque,
35. Winsor and Newton Sap Green permanent, Transparent,
3. MMMC, Liquitex Carbazole Dioxazine Purple,
24. Grumbacher Dioxazine Purple, Transparent,
PV23:1r carbazole dioxazine = Purple