Red and black: What Color Do They Make?

Maroon

Red + black = maroon. With more red you get brick red; with more black, dark brown.

More shades from the same colors

Brick red2 parts red + 1 part blackDark brown1 part red + 2 parts blackLight maroonmaroon + whiteDark maroonmaroon + black

Put the color down first and add black little by little: a little black darkens a lot.
To darken without dulling the color, try a darker shade of the same color instead of black.

What color do red and black make?

Red + black, in equal parts, make maroon. With more red it leans toward brick red, and with more black, toward dark brown.

What ratio of red and black should I use?

Half and half makes maroon. 2 parts red to 1 part black gives brick red; 1 part red to 2 parts black gives dark brown.

How do I make maroon lighter or darker?

Add white little by little to lighten it (light maroon) or a little black to darken it (dark maroon).

Is it the same with watercolor, acrylic and oil?

The result is similar. Watercolor looks lighter because the white paper shows through; acrylic gets a little darker as it dries.