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Digital Imaging Basics Intro to Digital Design 1
Digital Imaging BasicsIntro to Digital Design 1
Digital Imaging BasicsDigital Imaging Basics
PixelsThe foundational building block of a digital image is the
“Picture Element”or
“Pixel”
Characteristics of pixels:1. Uniformly square
PixelsThe foundational building block of a digital image is the
“Picture Element”or
“Pixel”
Characteristics of pixels:1. Uniformly square2. Positioned in vertical and horizontal rows3. Viewed together, they give the impression of a continuous image
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
• small sized pixels• anti-aliasing
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
• small sized pixels• anti-aliasing
PixelsThe foundational building block of a digital imagePixels
The foundational building block of a digital image
Characteristics of pixel-built images:1. Curves must be perceived through optical illusion
• small sized pixels• anti-aliasing
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an imageUnderstanding pixel dimension:1. A pixel is thought of as a “dot” of light or ink2. These dots fill an area of 2-dimensional space3. Geometry measures dimension as width x height
3
3. Geometry measures dimension as
8
8 x 3 = 24 total pixels
Understanding pixel dimension:1. A pixel is thought of as a “dot” of light or ink2. These dots fill an area of 2-dimensional space3. Geometry measures dimension as width x height
3
3. Geometry measures dimension as
8
Pixel dimension is “8 by 3”
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Understanding resolution:4. Additional geometric data (in inches) indicates pixel size
1 inch
2 pixels or dots per inch
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Understanding resolution:4. Additional geometric data (in inches) indicates pixel size
1 inch
6 pixels or dots per inch
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Understanding resolution:4. Additional geometric data (in inches) indicates pixel size
1 inch
12 pixels or dots per inch
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Understanding resolution:4. Additional geometric data (in inches) indicates pixel size
1 inch
24 pixels or dots per inch
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Understanding resolution:4. Additional geometric data (in inches) indicates pixel size
1 inch
72 pixels or dots per inch
ResolutionA measurement of visual “image quality,”
based on the size and number of pixels in an image
Resolution
402
301
301 x 402 = 121,002 pixels
72 dpiAll computer displays project 72 pixels in each inch of screen
1 inch
A measurement of visual image quality
900
900 x 1,111 = 1 Million pixels
1,111
ResolutionA measurement of visual image quality
900
900 x 1,111 = 1 “Megapixel”
1,111
ResolutionA measurement of visual image quality
223
167 40 dpi1 inch
ResolutionA measurement of visual image quality
167
125 30 dpi1 inch
ResolutionA measurement of visual image quality
111
83 20 dpi1 inch
ResolutionA measurement of visual image quality
56
42 10 dpi1 inch
ResolutionA measurement of visual image quality
28
21 5 dpi
As dpi drops:Pixel dimension decreases
Pixel size increasesOutput quality decreases
1 inch
ResolutionA measurement of visual image quality
ColorPerceived color is created by mixing and separating light
ColorPerceived color is created by mixing and separating lightPerceived color is created by mixing and separating light
ColorPerceived color is created by mixing and separating lightPerceived color is created by mixing and separating light
primary
primary primary
secondary
secondary
secondary
ColorColorPerceived color is created by mixing and separating light
RED
GREEN BLUE
ColorColorPerceived color is created by mixing and separating light
R
G B
Red, Green, and Blue = “RGB Image Mode”
ColorColorRGB image mode = color data stored in “channels”
ColorPerceived color is created by mixing and separating light
“What image mode?”
Image mode is a description of what color channels are used to define a digital image.
Image mode is a description of what color channels are used to define a digital image.
3 channelsRed, green, blue
ColorRGB image mode = color data stored in “channels”
Red channel Green channel Blue channel
ColorRGB image mode = color data stored in “channels”
RR GG B
Color
R G BR G B
C M YC M Y K
Color
C M Y K
RED
GREEN BLUE
Color
secondary
secondary
secondary
Color
C M Y K
Color
yellow
cyan
magentamagenta
ColorColor
Pixels
Resolution
The foundational building blocks of a digital image
A measurement of visual image quality
Created by mixing and separating light
• square; arranged in grid• curves are perceived through optical illusion
• Pixel dimension = total number of pixels in image• DPI = relative size of pixels; computer screen is 72 dpi
• Color information stored in channels (3-channel RGB)• Each color present at level of 0 to 255• Hue, saturation, and brightness (HSB) vary
