photoshop4

Image basics - Grayscales

   
   

Difference between Grayscale and Black & White

In computing, a grayscale digital image is an image in which the value of each pixel is a single sample. Displayed images of this sort are typically composed of shades of gray, varying from black at the weakest intensity to white at the strongest, though in principle the samples could be displayed as shades of any color, or even coded with various colors for different intensities. Grayscale images are distinct from black-and-white images, which in the context of computer imaging are images with only two colors, black and white; grayscale images have many shades of gray in between. In most contexts other than digital imaging, however, the term “black and white” is used in place of “grayscale”; for example, photography in shades of gray is typically called “black-and-white photography”
   
tip
Hue & Saturation are useless values in color to grayscale conversion.
Only the Brightness Luminosity is of use. SEE Color to GRAYSCALE for more information
   
 

Hue: is one of the main properties of a color described with names such as “red”, “yellow”, etc. The two other main properties are lightness and colorfulness. Hue is also one of the three dimensions in some colorspaces along with saturation, and lightness

   
Hue
Saturation
Luminosity
Saturation: which is the amount of gray in a particular color. A color with more gray is considered less saturated, while a bright color, one with very little gray in it, is considered highly saturated. The amount of saturation does not affect the basic hue of a color and it also is unrelated to the value (amount of light or darkness in a color.) For example, if we take away the colors in an image, the tonal values will remain. However, taking away the colors themselves will make the image completely unsaturated. A more saturated color is also called a more ‘pure’ color because it is undisturbed by gray.

PROBLEM

Color to Grayscale

Notice how the 4 colors on the left convert to 2 shades of gray!
see Color to Grayscale for help on this
hue
 

Luminosity: relative brightness of something.

 

light

“Shadow is a colour as light is but less brilliant;
light and shadow are only the relation of two tones”.
Paul Cezanne

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