Can we make red colour by mixing two colours?

Can we make red colour by mixing two colours?

Red is a primary color that cannot be created by mixing other colors. This is because red has a specific wavelength of light that defines it within the visible color spectrum. Other colors like orange, purple, and brown can be created by mixing red with other primary or secondary colors, but red itself cannot be recreated through color mixing.

The Primary Colors

There are three primary colors – red, blue, and yellow. Primary colors are those that cannot be created by mixing other colors together. All other colors are derived from some combination of these three primary pigments. This is known as the subtractive color model, which applies to pigments, dyes, and surface colors.

When it comes to light instead of pigments, the additive color model is used. The primary colors of light are red, green, and blue. Combining these colors in different proportions produces all the visible colors of light. But with either model, red is considered a primary color that cannot be created by mixing other colors.

Why Red Cannot be Mixed

Red has a predominant wavelength range of approximately 620-750 nanometers. This wavelength range corresponds to light in the red portion of the visible spectrum. Our eyes contain cone cells that are sensitive to this wavelength, allowing us to perceive red.

No other color has this specific red wavelength. When you mix colors, you are combining different wavelengths of light. For example:

Color	Wavelength range
Red	~620-750nm
Green	~495-570nm
Blue	~450-495nm

Mixing green and blue makes a color like cyan or teal. This adds wavelengths in the blue and green range, but there is no contribution of red wavelengths. No combination of other colors can produce that critical red wavelength needed to make our eyes perceive red.

Physically, red has the longest wavelength visible to the human eye. The only way we see red is when that unique long wavelength light interacts with our eye. Mixing other colors cannot recreate such long wavelengths, so red will always remain a primary color that cannot be successfully mixed.

Exceptions with Light Mixing

There are some exceptions where mixing other colors of light can produce red:

– Laser/phosphor mixtures: Some red lasers use an infrared laser diode combined with a red phosphor material that converts the light to red wavelengths. But this is reliant on advanced technology, not simple color mixing.

– Combining non-primary colors: Mixing certain non-primary colors like magenta and orange can skew toward red wavelengths since those colors already contain red components. But the results are not a pure red.

– CMYK printing: Combining cyan, magenta, and yellow ink pigments can create a close approximation of red due to the light absorption properties of the pigments. But it still does not produce a true primary red wavelength.

So while some red hues can be achieved through complex mixing, it is not possible to make pure red by mixing other primary or secondary colors. Red maintains its primary color status.

Mixing Colors that Appear Red

As described, directly mixing colors cannot yield pure red. But you can mix colors that appear reddish or orange to create different hues of red:

– Red + Yellow = Orange
– Red + Blue = Violet
– Red + White = Pink
– Orange + Purple = Red-violet

By starting with red and adding small amounts of other colors, you can skew the hue and lightness/darkness of red. This takes advantage of red’s anchoring wavelength and mixes in other wavelengths to modify the end result. So while red cannot be built from other colors, it can be used with other colors to generate rich variations.

Light vs. Pigment Mixing

Another factor that affects color mixing is whether we are working with light or pigments/paints.

Light mixing uses the additive model where combining color wavelengths produces different hues. This is employed with projected light like TVs, computer monitors, projectors, and more. But as described, additive mixing cannot recreate pure red solely from mixing green and blue light.

Pigment mixing follows the subtractive model. Paints and other pigments work by absorbing certain wavelengths and reflecting the unabsorbed wavelengths back to our eyes. So mixing paints produces different effects than mixing light. However, red pigment still cannot be created by mixing other paint colors for the same reasons around wavelength and human color perception. Red remains primary in both models.

Computer Color Models

Looking at how colors are defined digitally also shows red’s primary color status:

– RGB model: Red, green, and blue values define all digital color. Red has its own channel and cannot be recreated by mixing green and blue.

– CMYK model: Used for printing. Black is added to CMY since mixing CMY pigments does not create true black. But red still remains independent.

– HSL model: Defines colors by hue, saturation and lightness. Red has its own distinct hue value that cannot be reached by mixing other hue values.

Computer color picking tools all allow selecting red as a distinct color that sits outside what can be mixed from other colors.

The Visible Spectrum

Examining the visible color spectrum also shows why red stands alone. This is the continuous distribution of colors that can be produced by different wavelengths of visible light:

Violet

Indigo

Blue

Green

Yellow

Orange

Red

Red sits at the long wavelength end. Mixing colors from the middle of the spectrum cannot shift wavelengths long enough to reach red. No color mixing can magically generate those longer red wavelengths of light.

Pigment and Dye Mixing

The same principles apply to mixing paint pigments or dyes. Take a look at this color mixing chart showing results from mixing common paint colors:

No combination of paints on this chart can produce red because no other pigments contain red’s unique wavelength signature. The same applies to mixing dyes for fabrics and other materials. Red maintains its primary color status within the world of pigments and dyes.

Why Red is Special

Not only is red undefinable by color mixing, but it has special properties that set it apart:

– Longest wavelength visible to human eyes

– Grabs our attention more than other colors

– Associated with intensity, excitement, danger, passion, energy

– Produces a physical reaction, raising pulse and breathing rates

– Visible best under low light conditions due to long wavelength

Red has an unmatched emotional impact and visibility thanks to its defining wavelength. This further builds its case as a primary color that cannot be replicated by mixing other colors. Red holds a special place on the visible spectrum.

Conclusion

Red is universally considered a primary color precisely because there are no ways to recreate its vivid hues through mixing other colors of light or pigment. Scientifically speaking, red has a specific wavelength range that triggers our eyes’ red color receptors. No blending of shorter, middle wavelengths can generate this length needed for true red. Red also sits alone as the longest wavelength humans can perceive, adding to its uniqueness.

While mixing colors can produce amazing hues, true, pure red will always stand out as the fixed point the color spectrum revolves around. Red commands attention, heightens emotion, and defines one pole of color vision. This makes red fundamentally a primary color that cannot be generated by mixing other colors. Over centuries of color theory and science, red has maintained its special status in color mixing. So while red can be lightened, darkened, or skewed, its vivid presence on the visible spectrum remains unmixable and unforgettable.