Green and purple are secondary colors that appear opposite each other on the color wheel. When mixed together in painting or light, they produce a shade of blue. The specific reason this occurs has to do with the way our eyes perceive color through additive and subtractive color mixing. Understanding these color mixing principles can help explain why combining green and purple pigments or light creates a blue hue.
Additive vs. Subtractive Color Mixing
There are two main ways that colors mix together – additive and subtractive color mixing. Additive color mixing involves combining colored lights, while subtractive color mixing involves combining pigments.
Additive color mixing uses red, green, and blue (RGB) light. When all three are combined, they create white light. If green and red lights mix, they make yellow. Red and blue make magenta. Green and blue lights mixed together make cyan.
Subtractive color mixing uses pigments, such as paints, dyes, or inks. The primary colors are cyan, magenta, and yellow. Combining these pigments subtracts wavelengths of light and creates new colors. Cyan and yellow make green. Magenta and yellow make red. Cyan and magenta make blue.
The key difference is that with additive mixing, combining colors adds light waves, while subtractive mixing subtracts or absorbs certain wavelengths.
The Color Wheel
The color wheel shows the relationship between primary, secondary, and tertiary colors. On the wheel, primary colors sit opposite one another, while secondary colors are created by mixing the primaries on either side.
For additive mixing with light, the primaries are red, green, and blue (RGB). For subtractive pigment mixing, the primaries are cyan, magenta, and yellow.
The secondary colors are green, purple, and orange for RGB light mixing. For pigment mixing, they are green, purple, and red.
Tertiary colors are created by mixing a primary with a neighboring secondary. For example, yellow-green, blue-green, and red-purple.
Why Green and Purple Create Blue
With this background on color theory, we can now explain why mixing green and purple creates a shade of blue.
Light Mixing
When working with light, green and purple are secondary colors on opposite sides of the additive RGB color wheel.
Green light is made by combining the primary colors blue and green. Purple light is made from combining red and blue light.
When these mix, the red wavelengths from purple light get absorbed by the green. This leaves just the blue light waves, creating a blue color.
The specific shade of blue will depend on the intensities of the green and purple light that mix. A more vivid purple and darker green will make a deeper blue. With paler shades, the blue tint will be lighter.
Pigment Mixing
In terms of pigment mixing with paints, dyes, or inks, the same principle applies. Green pigment absorbs red and blue light wavelengths. Purple pigment absorbs green and blue light.
When mixed, the purple absorbs the green wavelengths while the green absorbs the red wavelengths from the purple. The only wavelength left in the reflected light is blue, creating a blue color.
Again, the particular blue shade depends on the pigment intensity and proportions used. Mixing a deep violet purple and forest green will make a midnight blue. A lilac purple and mint green will create a sky blue.
Examples
We can see these color mixing principles at work with both light and pigment mixing.
Light
Purple and green stage lighting can mix to create blue hues. Computer screen pixels displaying purple and green will blend to form blue. Purple and green fireworks exploding together make blue bursts in the sky. A purple neon sign next to a green one will cast a blue glow.
Pigment
In painting, combining purple and green acrylics, watercolors, or oil paints makes a shade of blue. Dyeing fabric purple and green results in blue where they blend together. Printing purple and green ink overlaps will create blue. Mixing purple and green colored candies or cake batter produces blue swirled color effects.
The Science Behind It
The specific scientific principles governing how green and purple create blue have to do with the wavelengths of light that correspond to each color.
Visible light from violet to red occurs in wavelengths of 400-700 nanometers (nm). Green light is around 500-565 nm. Purple is a mix of blue (450-495 nm) and red (620-750 nm).
When these wavelengths mix additively in light or subtractively in pigments, the red wavelengths from purple and the green wavelengths from green are absorbed or subtracted out. This leaves only the blue wavelength remnants, causing our eyes to perceive the color blue.
This is the same reason red and green make yellow when mixed. The blue gets absorbed out, leaving just the middle yellow wavelength.
Color Mixing in Action
To help visualize these color mixing principles, here is a table showing examples of mixing different color pairs and the resulting colors:
| Color 1 | Color 2 | Mixed Color |
|---|---|---|
| Red | Green | Yellow |
| Blue | Yellow | Green |
| Purple | Green | Blue |
As shown, combining opposite colors on the color wheel results in a mixture of the two. Red and green make yellow. Blue and yellow make green. And purple mixed with green yields blue.
Applications
Understanding that purple and green make blue is useful for many color mixing applications:
– Painting and pigment mixing – Artists can utilize this relationship to create new shades and hues of blue by blending purple and green paints. This is useful for color gradients.
– Digital design – UI designers, graphic artists, and web developers working with RGB colors can mix purple and green codes to generate appealing blues.
– Lighting and theater – Lighting directors can use purple and green gels/filters to produce blue light on stage.
– Textile dyeing – Those dyeing fabrics or yarns can blend purple and green dyes to achieve blue coloration.
– Food coloring – Mixing purple and green food dyes or gel colors results in blue tones for icing, candy, cakes, etc.
– Fireworks/pyrotechnics – Fireworks with purple and green coloring burn together to create blue bursts.
– Education – Teachers can use this color mixing example when educating students about principles of additive/subtractive color mixing.
So in summary, the blending of purple and green to create blue is a fundamental color theory concept with many practical uses across art, design, science, and education. Unpacking the light and pigment interactions helps explain why this vivid mixing effect occurs.
Conclusion
When purple and green mix together, whether in light, paints, dyes, or other pigments, they produce a shade of blue. This is because purple light/pigment absorbs green wavelengths, while green absorbs red wavelengths. With just the blue wavelength left, our eyes see the result as blue. The particular hue depends on the purple and green shades used. Understanding the interplay of colors on the color wheel helps explain this vivid mixing effect that has many applications across different fields.