Adventures In Color Mixing

Summary: Can a piece of software teach us how to mix colors? It may serve as a good starting point for beginner artists who need some sort of basic guidance. However, as palette choices expand, color mixing software either does not address the brand of colors an artist has chosen, or the software fails to capture the full extent of color bias that exists in the real world of pigments. Keywords: Adventures In Color Mixing

Closeup of painting palette

Color mixing is probably one of the most deeply internalized tasks an artist learns. Like many skills that can be mastered by instruction, after some fundamentals become comfortable, the real challenge begins. One of my mentors, the late Zora Pinney who owned an art materials store in Los Angeles, told me years ago that I should practice the discipline of viewing specific objects and mentally figure out what colors would be required to duplicate the color of the object using pigments. Without some prior basic understanding and experience as to how colors interact, Zora’s guidance is akin to taking a first sky diving jump and the only instruction provided is: “Step out of the aircraft.”

While some artists scorn the use of a color wheel to provide knowledge of the interaction of colors, it visually maps the relationships between adjoining and opposite colors within the wheel. Everyone needs to know what happens when complementary colors are mixed. We must understand what is needed to heighten or neutralize a color. Most landscape painters I know will lower the chroma of colors that come straight out of a tube of paint. Commercially available pigments do not mimic the hues and chroma of the landscape, so neutralizing and shaping colors is key to determining the correct values and hues in a landscape painting. Artists desiring to paint high chroma pictures would be handicapped if hues were low in chroma which only served landscape painters since chroma cannot be increased by mixing hues. (Disregard using white with some organic, synthetic colors to spike their chroma higher to some extent.)

The tricky part comes when artists try to exactly match a color they are observing. The color of the ambient light illuminating the scene and the color of the light around the palette will be different because the artists must maintain their palette shaded from direct sunlight. Reflected light from an artist’s clothing or umbrella will potentially interfere with achieving perfect color fidelity.

However, the human brain is amazing. We compensate for differences in local light versus the light within the scene being depicted. We calculate color temperature and select warm or cool colors appropriately. We limit the values of colors to solidify a painting.

The other tricky part that only comes with mixing experience is learning the bias of the paints we use. Some artists appear to labor over understanding color bias while others intuitively know how to control and master the subtle underlying effects of color undertones.

Color bias is easy to visualize when a spectrophotometer is used to reveal the characteristics of a pigment’s spectral signature. Every pigment transmits all the colors of the spectrum that humans can see, (from violet at 380 nanometers to red at 740 nanometers) but some portions of a pigment emanate more parts of the spectrum than other parts thus blocking some of the transmission of the other hues.

Think about a color for a moment as if it were a choir composed of several singers all singing different parts at different volumes. If the baritones are singing very loud and the sopranos, altos, and bass are all singing softly, you still hear the entire choir, but the focus will be on the baritones. They are all singing, and you hear them all but at different intensities. Spectrally, color acts the same.

For example, compare phthalocyanine blue and cobalt blue. Disregard, for the moment, the tinting strength of phthalo blue. The spectral signature of cobalt blue has a fair amount of violet, green, and red that creates a bias to the dominant blue part of the spectrum that has us see blue when we open a tube of cobalt blue color. Compare that to phthalocyanine blue that very little violet or red portions of the spectrum and a whole lot of blue transmission.

Now imagine, or if you prefer, test this for yourself. Mix cadmium yellow light with cobalt blue, then mix phthalocyanine blue with cadmium yellow light and compare the results of the two green colors you created. The phthalocyanine and cadmium yellow mixture will produce a more intense, high chroma green because phthalo blue has very little red in it which is the complement of blue. Cobalt blue has a lot of red in its spectral signature and now because a green mixture is created, the red neutralized the green to some extent to produce a dull green hue.

This is a simple example. It gets worse when more colors are mixed and amplified further when more colors are added to a palette. Artists master complex palettes but there is something to be said for maintaining a limited color palette, especially when starting out as an artist. Underlying color bias tends to cancel/neutralize hues and result in what artists affectionately call, “making mud.”

I have organized and posted the spectral reflectance signatures of many commonly used colors on this page on the website. CLICK HERE to view it. While this is deep into nerd territory, if you can tolerate reading a single line graph with visually helpful x and y-axis indicators, you might find the information useful in guiding your adventures in color mixing.

Returning to the subject of computer applications that virtually mix colors, only the ones that focus on artists’ pigments are helpful. Many color mixing applications are made to help web designers by mixing colors that don’t exist in the pigment world. Others give an overview of how primary colors interact and how to create secondary colors. The non-pigment-oriented color mixers do not account for color bias found in actual pigments.

The Syntax of Color

Author's Note: Vacation season is over and accounts for a prolonged absence from writing. Refreshed and recharged by recent trips to Glacier National Park, Banff National Park in Canada, Rocky Mountain National Park and Mesa Verde provided some outdoor inspiration along with a good degree of altitude-induced oxygen deprivation.

An announcement and more information on a collaborative effort researching hardboard panels will be posted soon.