Today I want to tell some notes about the use of primary and secondary colors of the color wheel. See at the following simple color wheel:
The primary colors azul (blue) - rojo (red) - amarillo (yellow) are placed in the center as a triangle. If you mix EQUAL parts or proportions of each color pair on each side of the triangle, you can obtain the corresponding secondary color (orange - green - violet). Then, for example, you don't need to buy these secondary colors, and only focuse on the three primary ones. It means:
1 part yellow + 1 part red = orange (naranja)
1 part yellow + 1 part blue = green (verde)
1 part blue + 1 part red = violet (violeta)
Continuing with the mixing, if you mix equal parts of primary and secondary colors, you can obtain the tertiary ones. It means:
1 part orange + 1 part yellow = yellow-orange (amarillo-nararja)
1 part yellow + 1 part green = yellow-green (amarillo-verde)
1 part freen + 1 part blue = blue-green (azul-verde)
1 part blue + 1 part violet = blue-violet (azul-violeta)
1 part violet + 1 part red = red-violet (rojo-violeta)
1 part red + 1 part orange = red-orange (rojo-naranja)
The tertiary colors are mostly present in nature, and them are mostly used in art works. Varying the proportions of the colors you can obtain different hues, and if you add white you can obtain soft or clearer colors. You can use also more primary or secondary colors to obtain more intensity in your mix result. Some people uses black color to obtain more darkness. My recomendation is to not use the black to obtain intensity because it not funtions well; the black usually dirty the color.
When you mix, take in acoount that is more easy to make a color darker than clearer. For this reason I recomend to begin the mix putting the clearer colors at first and then add slowly the dark colors and mix very well during the addition to see the resulting color you are obtaining, and then stop adding when you reach your desired result. For example if you want to obtain orange color put first the yellow (clearer) and then add slowly the red (darker), but not the entirely part of it, only a small quantity at once and mixing to homogenize the mix.
The hint is to practice, and experiment with color mixing to create your own color palette, indicating the amount of paint used for it, and the order in which you added the colors. An important thing is to consider the color of paper where you will paint, because it intracts with visual effect of the final color paint.
Hope these few explanations can help all of you in your work. Good painting to all!