Tone, Mass tone & Undertone, Oh My!

Usually we want harmonious color combinations  derived from color relationships. However nothing undermines color harmony than clashing undertones.

It's sometimes referred as 'mud' and it happens when you mix paint to the point at which no hue family such as red, orange, yellow, green, blue or violet is evident.

Mixing all of the three traditional primary colors together makes a brown muddy color as expected but, why do we get mud when mixing other colors?

It's due to the undertone, and when mixing color, it's often called pigment or color bias. 

Tints, Tones & Shades

A tone is a single color swatch. Alone by itself, it has a unique combination of color characteristics including hue, value, intensity and temperature.

Tone is also sometimes defined as any color that has been mixed with grey or a tone of grey.

A 'tint' is any tone mixed with white and a 'shade' is any tone mixed with black.

Mass tone

The color or 'hue' you immediately identify is mass tone, it is the color of the paint. Painters also refer to this as 'body color,'  'top tone' or 'mass color.'

You may also sense mass tone when the paint is of a generous thickness, highly concentrated, or undiluted when light can not get through and reflect off of the substrate below. If too dark, you may have to add a small touch of white to determine the color.

Paint colors are at their strongest intensity when they are straight out of the tube. However mass tone may vary slightly within each pigment from one paint manufacturer to another depending on manufacturer's own proprietary recipe or the amount of pigment concentration used.

Undertone

Oil paint, pastels, watercolors and opaque watercolors, i.e. gouache are manufactured from pigments. Due to the manufacturing process of grinding & mixing, there are small impurities that exist within each type of pigment. This pigment bias creates an 'undertone.'

Undertone is often concealed when a color is viewed in isolation. However, it becomes apparent when the color is compared to another color within the same hue family, used in combination with other colors or mixed.

Mass tone vs. Undertone

Mass tone is what you identify first; it’s the color. The closer the undertone is to the mass tone, the truer the color will appear. In some colors, the mass tone and undertone are very similar; other colors have undertones that are quite different from their mass tone.

For example, some reds will lean more yellow or orange, while others will slant more violet or blue.
Note that undertones are also slightly different depending on the manufacture (i.e. they may have a different ratio of additives, medium or pigment impurities).

Determining Undertone

The red oil paint tones below may look similar at first glance but when compared to each other you can see subtle warm or cool undertones. Warm undertones have more yellow. Cool undertones have more blue.

Red Oil Paints Manufactured by Holbein

The mass tone and undertone should work together to create a harmonious color scheme or lean toward the color you are mixing. Understanding how to select the correct colors or when mixing is important, but selecting the correct color that also has the right undertone is even more important.

Skilled painters use their experience to take the guesswork out of this process. However for those just learning, brushing paint swatches out thinly on a white ground with one paint swatch next to another is the simplest way to find the undertone.