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Digital Still ImagesDigital Still Images
ETT 555ETT 555
14 June 2004 14 June 2004
Digital ImagesDigital Images Uses
Multimedia projects Email Prints Web CBL ?
Digital Image Digital Image CategoriesCategories
““Artsy”Artsy” Drawings (create)Drawings (create) Clip art (get, don’t create)Clip art (get, don’t create)
RegularRegular AnimatedAnimated
““Realistic”Realistic” PhotosPhotos
Image Technical Image Technical DetailsDetails
Digital Graphics Types (+ / -)Digital Graphics Types (+ / -) Bitmap (aka “raster”)Bitmap (aka “raster”)
= Pixels (picture elements)= Pixels (picture elements) Used for detailed art / photosUsed for detailed art / photos
VectorVector =Formulas for component =Formulas for component objectsobjects Used for clip art, CAD, etcUsed for clip art, CAD, etc
Cf. fontsCf. fonts
Digital Image Digital Image CreationCreation
Draw / Paint SoftwareDraw / Paint Software Create drawings, clip artCreate drawings, clip art Bitmap or vectorBitmap or vector Time consumingTime consuming Need artistic talentNeed artistic talent
Tools, e.g. graphics tabletsTools, e.g. graphics tablets Examples: Examples: Paint, FreehandPaint, Freehand
Digital Image Digital Image CreationCreation
Direct “Copies”Direct “Copies” Scanner (prints, slides, Scanner (prints, slides, strips)strips)
Digital camerasDigital cameras Digitizing boards (video)Digitizing boards (video) Bitmaps onlyBitmaps only
Digital Image Digital Image CreationCreation
““Borrow” from web pagesBorrow” from web pages Right-click; save (target) as Right-click; save (target) as . . .. . .
Legal issues?Legal issues? See copyright section on webSee copyright section on web
Digital Image Digital Image ManipulationManipulation
Graphics softwareGraphics software ““Fix” problemsFix” problems
Light / darkLight / dark ColorColor ““Retouch” (hair, red eye, etc.)Retouch” (hair, red eye, etc.)
Add interestAdd interest Special effects (“filters”)Special effects (“filters”) Combine for “new” imagesCombine for “new” images
Still Image Still Image HardwareHardware
Digital Camera Precursors “Xapshot” (analog) Apple QuickTake
Still Image Still Image HardwareHardware
Digital Camera Features Resolution (megapixels)
How many do you need? Zoom type and ratio
Optical vs Digital More __X is better
Still Image Still Image HardwareHardware
Digital Camera Features Storage medium
Capacity Flexibility Speed of save Card types
Transfer to computer methods Cable (issues) Card reader
Still Image Still Image HardwareHardware
Scanner Types / Features Flat bed
Bed size Transparency Adapters ADF
Sheet Convenient, but limited
Slide Auto feeder?
Still Image Still Image HardwareHardware
Scanner Features Interface method
Early Now
Scanners & Resolution What do you “need”?
Digital Image Size Digital Image Size FactorsFactors
Physical Size (on screen)Physical Size (on screen) Initial size (in/cm, if scanned)Initial size (in/cm, if scanned) Screen resolution (variable)Screen resolution (variable) Image resolution (variable)Image resolution (variable) Scaling (not all software has)Scaling (not all software has)
MS Viewer = YMS Viewer = Y PowerPoint = Y/NPowerPoint = Y/N Browsers = NBrowsers = N
Digital Image Size Digital Image Size FactorsFactors
Physical Size (printer Physical Size (printer output)output) Image file dimensionsImage file dimensions Printer resolution (dpi)Printer resolution (dpi) Printer vs image resolutionPrinter vs image resolution Software “scaling”Software “scaling”
Your softwareYour software Photo finishersPhoto finishers
Digital Image Size Digital Image Size FactorsFactors
Physical Size (screen, print)Physical Size (screen, print) File SizeFile Size
Image pixel dimensionsImage pixel dimensions Color depth (1-24 bits)Color depth (1-24 bits)
Calculate base examplesCalculate base examples File format impactFile format impact
CompressionCompression Preserve a HQ originalPreserve a HQ original
Impact of File SizeImpact of File Size
K/sec 100K 1MB
28.8K 3.0 33 sec 6 min
56K 6.0 17 sec 3 min
T1 Cable / DSL
150 variable
0.7 sec 7 sec
Digital Image Size Digital Image Size FactorsFactors
Physical Size Physical Size File SizeFile Size Graphic file formats Graphic file formats
(examples)(examples) jpg, gif, bmp, png = bitmapsjpg, gif, bmp, png = bitmaps tif, tga, bmp = top qualitytif, tga, bmp = top quality wmf, cgm = vectorwmf, cgm = vector pcx/pct/pict pcx/pct/pict = obsolete= obsolete
Format Format CharacteristicsCharacteristics Color potential
“true” color (24-bit) B&W (gray scale, 8-bit) Line art (B or W, 1-bit)
File size “Raw” Compression
In digital cameras = “quality”
Format Format CharacteristicsCharacteristics(http://www.webopedia.com)(http://www.webopedia.com) JPG
Full, subtle color Compact, but “lossy”
GIF Limited color (#, areas) B&W (gray scale) Compact & lossless
PNG (http://www.w3.org/Graphics/PNG/) May equal quality of tif Flexibility of color depth, etc Not patented (as gif is)
Format Format CharacteristicsCharacteristics TIF
Full color Limited compression
BMP Full color Little/no compression
Format Format CharacteristicsCharacteristics WMF
Vector Microsoft clip art
CGM Some clip art
PCX Old clip art format
Typical Format Typical Format ChoicesChoices For best prints / “archive”
tif bmp psd (Photoshop)
For on-screen display gif jpg png
Working with Image Working with Image FormatsFormats
Load image Manipulate
Original Quality is the KEY Crop / Resize / Orientation Colors / Brightness / Contrast Color Depth Effects (“filters”)
Save as . . . (choose format)
Assignment & DemosAssignment & Demos