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Images - Coggle Diagram
Images
true colour
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True colour uses 1 byte for red, 1 byte for green and 1 byte for blue
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Red - 1 byte - 8 bits - 28 = 256 different reds,
Green - 1 byte - 8 bits - 28 = 256 different greens,
Blue - 1 byte - 8 bits - 28 = 256 different blues,
Number of possible colours = 256 x 256 x 256 = 16,777,216
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colour palette
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Bit/color depth = 2?,
To work out ?, work out what power of 2 equals the colour palette
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example, the colour palette is 16. what is the bit or colour depth,
2^? = 16
2^4 = 16
NUMBER OF AVAILABLE COLOURS NOT NUMBER OF BITS,
CONVERT TO POWER OF 2 TO FIND BIT DEPTH,
Colour palette means the number of colours that are available for each pixel.
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3 bit colour
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black is encoded as 000 and white as 111. The palette contains red, green and blue and their complementary colours cyan, magenta and yellow
The present standard most widely used is 24-bit representation. This means that the colour data for each pixel is encoded in 24 bits with 8 bits used for each of the primary colours : red, green and blue. Each colour in the palette is a combination of each of these in different properties
Using 8 bits allows 256 different levels of each of red, green and blue. Therefore 256 x 256 x 256 or 16,777,216 different colour variations are possible. This number of bits produces such as a realistic image it is described as being 'true colour
metadata
Metadata means 'data about data'. In other words, metadata describes the structure of the data file and is usually located right at the start of the file.
Metadata is stored in a format called Exif - Exchangeable image file format
Examples of metadata:
file format - eg JPEG, GIF or PNG
dimensions
resolution
colour depth
time and date the image was last changed
camera settings when the photo was taken
GPS location
Metadata takes up storage space so an image’s total file size will be a result of the binary code for each pixel and the binary code for the metadata
grayscale
Black, white and shades of gray
The larger the bit depth, the more shades of gray can be produced
A 2 bit grayscale image uses black, white and 2 shades of gray
8 bit colour
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Even though image files with more bits are available, 8-bit image files are useful for situations where there is limited bandwidth, available memory or storage capacity.
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Vector image
A vector image stores the mathematics required to draw a shape. For example, a circle can be drawn just by storing its:
XY coordinates from the middle
radius
width
colour
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pixel
Pixel stands for Picture element - it is the smallest element of a picture - each pixel is a small dot of colour
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