Mixing colors is a fun and interesting process that can result in new and exciting shades. Specifically, when you combine the primary colors blue and red, the result is the secondary color purple. Understanding how and why this happens provides insight into the nature of color itself. In this article, we will explore the basics of color theory and light to uncover the science behind mixing blue and red to make purple.
The Basics of Color
To understand what happens when we mix colors, we first need to review some color theory basics. The primary colors are red, blue, and yellow. These are the core pure colors that can be combined to create all other colors. When you mix two primary colors, you get a secondary color:
| Red + Blue | Purple |
| Red + Yellow | Orange |
| Blue + Yellow | Green |
The secondary colors are purple, orange, and green. Mixing two secondary colors results in a tertiary color, such as red-violet or yellow-green.
The color wheel visually demonstrates these relationships between primary, secondary, and tertiary colors:
| Image of color wheel showing primary, secondary, and tertiary colors |
So when we talk about mixing blue and red to make purple, we are combining two primary colors to create the secondary color purple.
The Nature of Light
To really understand what happens when we mix colors, we need to consider the nature of light itself. Visible light consists of different wavelengths along the electromagnetic spectrum. Our eyes detect these wavelengths as different colors:
| Red | Longer wavelengths (around 700 nm) |
| Orange | Slightly shorter wavelengths (around 600 nm) |
| Yellow | Middle wavelengths (around 570 nm) |
| Green | Slightly shorter wavelengths (around 500 nm) |
| Blue | Even shorter wavelengths (around 450 nm) |
| Violet | Shortest wavelengths (around 400 nm) |
When all wavelengths of the visible spectrum combine at full intensity, we perceive this as white light. The primary colors represent the main wavelength regions. For example, blue light stimulates the cones in our eyes that detect short wavelengths.
Mixing Colored Lights
Keeping the nature of light in mind, we can now consider what happens when blue and red light mix.
Blue light is at a wavelength of around 450 nm. Red wavelengths are around 700 nm. When these two wavelengths combine and enter our eye at the same time, our eye and brain perceive this combination of wavelengths as the new color purple.
More specifically, purple sits between blue and red on the spectrum, at wavelengths of around 400-450 nm. So by mixing the longer red wavelengths and shorter blue wavelengths, we stimulate the cones in our eyes that detect not just blue or just red, but the range in between – the purple wavelengths.
This is known as an additive mixture, where different wavelengths combine to create new permutations of possible colors our eyes can perceive. Starting with the primary red, green and blue wavelengths, thousands of intermediate colors can be created by mixing different intensities of the primaries.
Mixing Pigments
When we mix colored paints, dyes, or inks, we are mixing pigments. This is different from mixing light – here we are blending chemical compounds that absorb and reflect different wavelengths of light.
The primary pigment colors are cyan (reflecting green and blue), magenta (reflecting red and blue) and yellow (reflecting red and green). When two primary pigments mix, they create a secondary color by reflecting two primary wavelengths and absorbing the third.
For example, mixing magenta (reflecting red and blue) with yellow (reflecting red and green) creates red light + blue light = purple. The green wavelengths are absorbed.
So with pigments, we are mixing colors by reflection and absorption, rather than directly combining wavelengths as with light. But the secondary colors created are the same:
| Cyan + Magenta | Blue |
| Cyan + Yellow | Green |
| Magenta + Yellow | Red |
This is known as a subtractive mixture, where certain wavelengths are subtracted or absorbed. Starting with white light, the primary pigments subtract wavelengths to create all other colors.
Mixing Blue and Red Pigment
Specifically mixing blue and red pigments results in purple by the following process:
– Blue paint/ink absorbs orange and reflects blue and green.
– Red paint/ink absorbs cyan and reflects red and blue.
– When mixed, both the green and orange wavelengths are absorbed.
– The only wavelengths that remain to be reflected are blue and red light.
– Our eyes see this combination as purple.
So with pigments, we take away certain colors from white light by absorption, rather than directly combining wavelengths as with light sources. But the net result is still purple when blending blue and red.
Shades of Purple
We’ve seen that combining wavelengths of blue light and red light creates purple light. And absorbing orange/green from blue paint mixed with red paint that absorbs cyan also results in purple.
But there are many shades of purple that can be created by adjusting the proportions of the blue and red components. By increasing the amount of blue compared to red, we shift towards violet on the spectrum. With more red compared to blue, we shift towards red-violet hues.
Some examples of shades of purple created by mixing different proportions of blue and red:
| Color Name | Description |
| Violet | More blue, very little red |
| Blue-violet | More blue than red |
| Purple | Balanced mix of blue and red |
| Red-violet | More red than blue |
| Magenta | More red, very little blue |
So by adjusting the ratio of blue vs red, whether mixing light sources or pigments, we can create different hues and intensities of purple.
Cultural Associations
Beyond the scientific explanation, purple also has some cultural symbolism associated with it. In many cultures, purple is associated with royalty, spirituality, mystery, and creativity.
Some examples of purple symbolism include:
– In many European societies, purple robes were worn by royalty and people of authority. Purple dye was more expensive to produce which associated it with wealth.
– In Christianity, purple vestments are worn during the seasons of Advent and Lent as a symbol of penance and sacrifice. Purple is also used for Advent candles.
– Purple is associated with magic and mystery in works of fiction. For example, purple is a prominent color in the Harry Potter universe.
– Purple is seen as an unconventional color associated with creativity and the imagination. Figures like Prince and David Bowie adopted flamboyant purple outfits.
So the color purple has not only scientific origins, but rich cultural meanings as well. The synthesis of blue and red inspires a color of wealth, power, spirituality, creativity, and mystery in societies around the world.
Conclusion
When you mix blue and red, the result is purple. This can happen through directly combining wavelengths of blue and red light to stimulate the purple cone cells in our eyes. It also occurs by mixing blue and red pigments that absorb overlapping wavelengths and reflect back blue and red. Cultural associations give purple deeper meaning related to luxury, imagination, and spirituality.
The intersection of science, art, and culture gives such fascination to the process of mixing colors. Blending the primary colors blue and red to create purple provides a great example of how combining wavelengths and pigments can produce a new secondary color with a rich history of symbolic meaning. So the next time you mix together blue and red, think about the interesting science and culture behind the purple you created.
