Introduction Ingredients Spectra Attributes The Human Eye Color Mixing General Terms
Color Spaces How to measure Color Scales Color Effects After Images Contents


VISIBLE SPECTRUM on page 03.01

RAINBOW on page 03.02

PRISM on page 03.03

SOLAR SPECTRUM on page 03.04

INTERFERENCE on page 03.05




Electromagnetic radiation can be arranged in a "spectrum", that extends from waves of extremely low
and long "wavelength" to extremely high frequency and short wavelength.



The Visible spectrum is only a very small part of the Electromagnetic spectrum. In order of decreasing frequency or increasing wavelength, the Electromagnetic
spectrum consists of "Cosmic rays" , "Y-rays" , "X-rays" , ultraviolet radiation, Visible light, infrared radiation, microwaves and radio waves.


Electromagnetic radiation is an energy, 
produced by oscillation or acceleration of an electric charge.
 Electromagnetic waves have both 
electric and magnetic components.

The image alongside shows:

The Electric Field (blue colored)
The Magnetic Field (orange colored)
The Wavelength or Frequency
The Amplitude
Peak to Peak (2 x Amplitude)




Region General information "wavelength" "frequency" ENERGY


from up to from up to from up to

Cosmic-rays as a radiation of extremely high frequency and penetrating power that originates in outer space and consists partly of high-energy atomic nuclei.

10−14 m 10−12 m 300*1022 Hz 300*1020 Hz 1014 eV 1020 eV

Y-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. A form of electromagnetic radiation, similar to X-rays but of shorter wavelength. Y-rays and X-rays are also used therapeutically to kill tumor cells.

10−12 m  10−10 m 300*1020 Hz 300*1018 Hz 108 eV 1014 eV

X-rays have smaller wavelengths and therefore higher energy than ultraviolet waves. We usually talk about X-rays in terms of their energy rather than wavelength.

10−10 m 10−9 m 300*1018 Hz 300*1017 Hz 103 eV 105 eV
Ultraviolet light

Ultraviolet light (UV) has shorter wavelengths than the visible light. Though these waves are invisible to the human eye. Some insects, like bumblebees, can see them.

100 nm 400 nm 3*1017 Hz 0.75*1017 Hz    

The extreme ultraviolet (EUV) (UVC) is the ultraviolet light closest to X-rays, and is the most energetic of the three types.  UVC (100?230 is entirely absorbed by the ozone layer in the atmosphere and does not reach the earth's surface.

100 nm 290 nm 3*1017 Hz 1.03*1017 Hz    

The far ultraviolet (FUV) (UVB) lies between the near and extreme ultraviolet regions.. UVB rays are the tanning and cancer-causing rays.

290 nm 320 nm 1.03*1017 Hz 0.94*1017 Hz    

The near ultraviolet (NUV) (UVA) is the light closest to visible light with the longest-wavelength range. UVA rays are not harmful in normal doses and is used clinically in the treatment of certain skin complaints. It is also used to induce vitamin D formation in human bodies.

320 nm 400 nm 0.94*1017 Hz 0.75*1017 Hz 3.1 eV 103 eV
Region General information "wavelength" "frequency" ENERGY
Visible Spectrum

Visible light waves are the only electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength.

400 nm 750 nm 0.75*1017 Hz 0.40*1017 Hz 1.8 eV 3.1 eV
 Infrared light

Infrared light (IR) lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from violet light to red. 

750 nm 10-3 m 0.40*1017 Hz 300*1011 Hz 0.01 eV 1.8 eV

Near infrared light (NIR) is closest in wavelength to visible light. Near infrared waves are not hot at all - in fact you cannot even feel them. These shorter wavelengths are the ones used by our  remote control.

750 nm 140 nm 300*1011 Hz 2.14*1017 Hz    

Short wave infrared (SWIR)

140 nm 3000 nm 2.14*1017 Hz 0.10*1017 Hz    

Mid wave infrared (MWIR)  is even used to heat food sometimes - special lamps that emit thermal infrared waves are often used in fast food restaurants.

3 m 8 m 100*1014 Hz 37.5*1014 Hz    

Long wave infrared (LWIR)

8 m 15 m 37.5*1014 Hz 20.0*1014 Hz    

Far infrared light (FIR) is closer to the microwave region of the electromagnetic spectrum. Far infrared waves are thermal. In other words, we experience this type of infrared radiation every day in the form of heat! The heat that we feel from sunlight, a fire, a radiator.

15 m 10-3 m 20.0*1014 Hz 0.30*1014 Hz    


Microwaves have wavelengths that can be measured in centimeters! The longer microwaves, those closer to a foot in length, are the waves which heat our food in a microwave oven. Microwaves are good for transmitting information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke. Shorter microwaves are used in remote sensing. These microwaves are used for radar like the Doppler radar used in weather forecasts. Microwaves, used for radar, are just a few inches long.  This microwave tower can transmit information like telephone calls and computer data from one city to another.

 10-5   10-1     10-5  0.01
Region General information "wavelength" "frequency" ENERGY

Most weather radars have wavelengths that range between 0.8 centimeters (cm) and 10.0 cm.

>10-5     < 10-5  

A new 35 GHz (9 mm wavelength) cloud radar has recently been installed at Chilbolton to complement the existing 94 GHz (3 mm) "Galileo" radar at the site.

Radio Waves            


"spectrum" The term spectrum often loosely applied to any orderly array produced by analysis of a complex phenomenon. For example: an audio spectrum and a mass spectrum.
"frequency" ( symbol is  f ) is equal to the "Velocity of light" divided by the wavelength. ( f = 3 * 108 / λ )
"wavelength" ( symbol is  λ) is equal to the Velocity of light divided by the frequency. ( λ = 3 * 108/ f )  
The wavelength of light is so small that it is conveniently expressed in nanometers ( nm ) which are equal to one-billionth of a meter. Wavelength as the distance, measured in the direction of propagation of a wave, between two successive points in the wave that are characterized by the same phase of oscillation.
"X-rays"  A form of electromagnetic radiation, similar to light but of shorter wavelength and capable of penetrating solids and of ionizing gases. Often mentioned as Rntgen rays.
"Velocity of light"  ( symbol is  c ) is approximately 300,000 kilometers per second  
(about 186,000 miles per second ) ( c = f * λ )  ( c as m/s ) ( f as
"Hz" ) and ( λ as m )
"Hz" Frequency is expressed in Hertz (Hz)
A frequency of 1 Hz means: 1 cycle or oscillation per second.


Hertz, Heinrich, Rudolf 
 (German physicist) 
b-1857-02-22 Hamburg Germany 
Bonn Germany


Energy at the atomic level is commonly expressed in electron volts ( eV )

Length Conversion

1 nm = 10-9 m = 10-6 mm = 10-3 m
1 m = 10-6 m = 10-3 mm = 1000 nm

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xtremely High Frequency

EHF refers to Radio Frequencies (RF) in the range of 30 GHz to 300 GHz (or as wavelengths in the range of 10 mm to 1 mm) is known as the microwave band. 
This range of the spectrum is used for satellite communications.

uper High Frequency

SHF refers to Radio Frequencies (RF) in the range of 3 GHz to 30 GHz (or as wavelengths in the range of 10 cm to 1 cm)  is known as the microwave band.
This range of the spectrum is used for television and high-speed data services.

ltra High Frequency

UHF refers to Radio Frequencies (RF) in the range of 300 MHz to 3000 MHz (or as wavelengths in the range of 100 cm to 10 cm
This band is used for  mobile services, television, and non-communications services such as radar, space research, radio astronomy, and telemetry.

ery High Frequency

VHF refers to Radio Frequency (RF) in the range of 30 MHz to 300 MHz (or as wavelengths in the range of 10 m to 1 m).
This band is used for fixed communications services, ground-to-air communications, mobile services, and television.

HF Shortwave
igh Frequency

HF refers to the Radio Frequency (RF) band in the range of 3 MHz to 30 MHz (or as wavelengths in the range of 100 m to 10 m).
This band is used for fixed services, mobile services, amateur transmissions, broadcasting, and maritime mobile service. 

Medium Frequency

MF refers to the Radio Frequency (RF) band in the range of 300 kHz to 3000 kHz (or as wavelengths in the range of 1000 m to 100 m).
The regular AM broadcast band is found in this range.

ow Frequency

LF is the Radio Frequency (RF) band in the range of 30 KHz to 300 kHz (or as wavelengths in the range of 10 km to 1 km).
This band has more use for communications than ELF since it has a bandwidth that is large enough to provide reliable communications. 

ery Low Frequency

VLF refers to Radio Frequencies (RF) in the range of 3 kHz to 30 kHz. (or wavelengths in the range of 100 km to 10 km) and used for the very simplest signals such as Radio Navigation. 

ltra Low Frequency

ULF refers to Radio Frequencies (RF) in the range of 300 Hz to 3000 Hz. (or wavelengths in the range of 1000 km to 100 km

uper Low Frequency

SLF refers to Radio Frequencies (RF) in the range of 30 Hz to 300 Hz. (or wavelengths in the range of 10000 km to 1000 km

xtreme Low Frequency

ELF refers to Radio Frequencies (RF) in the range of 3Hz to 30 Hz. (or wavelengths in the range of 100000 km to 10000 km)