Varieties of the color blue may differ in hue, chroma (also called saturation, intensity, or colorfulness), or lightness (or value, tone, or brightness), or in two or three of these qualities. Variations in value are also called tints and shades, a tint being a blue or other hue mixed with white, a shade being mixed with black.

The modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin related to Old Dutch, Old High German, Old Saxon blāo and Old Frisian blāw, blau. The clear sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. When sunlight passes through the atmosphere, the blue wavelengths are scattered more widely by the oxygen and nitrogen molecules, and more blue comes to our eyes. An optical effect called Tyndall scattering, similar to Rayleigh scattering, explains blue eyes; there is no blue pigment in blue eyes. Distant objects appear more blue because of another optical effect called atmospheric perspective.

Amidst all the troubles,
A light is shining through,
With a glimmer of hope,
These many shades of blue.

EXIF Data

Camera Type: NIKON D3100
Lens: 18.0-55.0 mm f/3.5-5.6
Date Taken: 2/24/13
Aperture: f/8.0
Shutter Speed: 1/125
ISO: 800
Exposure Mode: Manual
Focal Length: 48.0 mm
White Balance: Auto
Metering Mode: Center Weight
Light Source (In Camera): N/A
Flash: N/A
Light Source (External): LED light
Size: 792 KB
Location: 4361 Custis Avenue, Sacramento, California
Latitude: 38,32.7424N
Longitude: 121,29.8172W
Elevation: 7.70 m