P I X E L

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P I X E L R E S O L U T I O N C O L O R D E P T
H C O M P R E S S I O N F I L E T Y P E S P H O
T O S H O P
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P I X E L P I C T U R E E L E M E N T
C R T
L C D
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R E S O L U T I O N S C R E E N ppi pixels per
inch Windows 96 ppi (dpi), but
fudged Macintosh 72 ppi Rule of thumb use
72 ppi P R I N T dpi dots per inch (print at
typically 300 dpi 150 dpi often acceptable) S C
A N dpi variable Rule of thumb scan at twice
the intended output resolution
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C O L O R D E P T H THE NUMBER OF COLORS A PIXEL
CAN DISPLAY DEPENDS ON HOW MANY BITS OF
INFORMATION CAN BE STORED FOR THAT PIXEL. THIS IS
CALLED BITS PER PIXEL
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C O L O R D E P T H INDEXED COLOR 1-BIT COLOR
(21 2 COLORS) MONOCHROME 2-BIT COLOR (22 4
COLORS) CGA 4-BIT COLOR (24 16 COLORS)
EGA 8-BIT COLOR (28 256 COLORS) SUPER
VGA WEB-SAFE PALETTE 216 COLORS
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C O L O R D E P T H RGB COLOR (PHOTOSHOP) 24-BITS
PER PIXEL WHICH IS THE SAME AS 8-BITS PER RED
CHANNEL 8-BITS PER GREEN CHANNEL 8-BITS PER BLUE
CHANNEL
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C O L O R D E P T H
1-BIT, 12KB
4-BIT, 36KB
8-BIT, 80KB
24-BIT, 224KB
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• C O M P R E S S I O N
• F I L E T Y P E S
• L O S S L E S S
• - RUN-LENGTH ENCODING - PCX, BMP
• RUNS OF SIMILAR COLORS STORED AS COLOR
• PLUS COUNT
• LZW (LEMPEL-ZIV-WELCH) - GIF AND TIFF
• REPLACES STRINGS OF DATA WITH SINGLE CODES
• L O S S Y
• - REDUCE BITS PER PIXEL - GIF
• - JPEG (JOINT PHOTOGRAPHIC EXPERTS GROUP)
• CODEC IS MIX OF VARIOUS TECHNIQUES INCLUDING
  RESPONSE OF THE EYE TO TYPES OF IMAGE

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• P H O T O S H O P
• - RESIZE
• - CROP
• - ROTATE
• - CORRECT COLOR
• - ADJUST CONTRAST
• - LAYERS
• - MASKING
• - TEXT
• BASIC SHAPES
• SCANNING
• EFFECTS (FILTERS)
• SAVE TO DIFFERENT FORMATS
• SAVE FOR DISPLAY ON DIFFERENT DEVICES