Use black food coloring if available
Mix equal parts red, blue, and green food coloring
Add a small amount of blue to deepen the color
Add a tiny amount of black gel coloring to darken the mixture
Use gel food coloring for stronger color
Start with a light base and add color gradually
Mix thoroughly after each addition
Let the color sit for a few minutes to deepen before adding more
Use cocoa powder or black cocoa for darker results in frosting or batter
Combine dark brown and blue coloring for a deeper black tone