• Sketch out at size (7 1/2 x 10") first
• Measure off your sketch the things you're going to scan in
• Scan things in at the size they will print at

Alphabet Soup

• SPI: Samples Per Inch
• Scanners
• Sometimes called DPI
• PPI: Pixels Per Inch
• Computer Displays
• Usually irrelevant
• Not the same as image resolution
• DPI: Dots Per Inch
• Laser and ink-jet printers
• Not an accurate measure of fidelity
• Often misused
• LPI: Lines Per Inch
• Offset lithography printing
• The number of lines per inch that can be resolved through a halftone screen

Image Resolution

• Image Resolution is in pixels
• The number of pixels wide by the number of pixels high
• Not relevant to things per inch

Screen Resolution

• Usually 72dpi
• Demo
• Capture the screen
• What is its resolution when you create a new Photoshop document with it?
• Demo
• Open this image in Photoshop
• What happens when you change the DPI but don't resample?
• Let's play with the print dialog…

Scanner Resolution

• Typically in DPI, bit it's really SPI
• More on this soon…

Camera Resolution

• Usually in pixels
• "Per Inch" is irrelevant

Printer Resolution

• Typically in DPI
• Typical printers are 600dpi
• Printer DPI is not equivalent to scanner DPI (which is really SPI)
• Project 1 target size is 7.5 x 10 inches @ 300dpi

So, then, what is the right resolution for your scans and photos?

• GIGO: Garbage In Garbage Out
• Scan & Photograph & Manipulate images at the correct resolution/size or at higher-than-you-need resolutions
• The more you change resolution, the more data is lost, and the fidelity of the image is reduced

Further Reading

• Photoshop CS3: Studio Techniques, p544
• Wikipedia on Image Resolution
• Scantips Basics
• Earthboundlight phototips

Screen

• WYSIWYG
• What You See Is What You Get
• NTSC
• National Television System Committee or
• Never The Same Color
• More about color next time…
• DPI is mostly pointless
• Color is largely relative
• Color is Additive (more in class 5)
• Because you are adding colored lightwaves
• Red and Green make Yellow

Print

• There is a sense of right and wrong about color
• Color is subtractive
• Because you are subtracting colors from a bundle lightwaves that is reflecting off a surface
• Red and Green make Brownish Gray

• What is Depth?
• If an image is X pixels wide and Y pixels high, then it can be said to have a depth of Z
• What is a Bit?
• 1 or 0
• Bits can be used for binary arithmetic

• Color Depth is measured in bits
• 8 bits: 10010100: 256 possible combinations
  (2 to the 8th power or 2x2x2x2x2x2x2x2)
• 24 bits: 101010011010100101011001: 2 to the power of 24
• 3 sets of 8 bits for Red, Green and Blue (RGB)
• Demo Photoshop's Color Palette
• 32 Bit
• 3 sets of 8 bits for RGB, one set for transparency
• Beyond 32 bits…

• How a scanner scans at howstuffworks
• Demo:How to do your scans

• Take photographs at the highest setting your camera can do
• Turn off any compression
• Get close to things you want to use for your project
• Use the close-up feature if available
• Use a tripod