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Graphic File Graphic File FormatsFormats
ObjectivesObjectives• Understand the difference between two
major categories of computer graphic images
• Investigate the differences between various file formats
• Generalize formats to the type of software that creates them
• Establish a philosophy of use for various graphic file formats
A usable description of any software's proprietary file format.
Native File FormatNative File Format
Two Categories of Two Categories of FormatsFormats
Bitmapped Vector
Bitmapped FormatsBitmapped Formats• Images are
created by individual pixels displayed in various colors.
Bitmapped FormatsBitmapped Formats• Remember,
each pixel can hold up to 24 bits (3 bytes) of color information
Bitmapped FormatsBitmapped Formats• Bitmapped
formats have a fixed resolution
• Can NOT be resized without some effects on the clarity of the image
Bitmapped FormatsBitmapped Formats
• Bitmapped formats are best suited for “photographic” quality images
Bitmapped FormatsBitmapped Formats• Scanners and
digital cameras acquire images in bitmapped formats
Common Bitmapped Common Bitmapped File FormatsFile Formats
• TIF
• JPG
• BMP
• PIC
• GIF
• PNG
• PSD
• PCX
TIF FormatTIF Format• Tagged Image File
format.• Standard between
MAC and PC bitmap graphics.
• Handles multiple channel files.
• i.e. RGB• i.e. Alpha Channels
TIF FormatTIF Format• Writes a "header"
that tells software what information is contained.
• Header may increase file size.– Not really a
problem with modern hardware
TIF FormatTIF Format• Uses a LZW
compression scheme.
• No data lost, just compressed.
JPG (Jpeg) FormatJPG (Jpeg) Format• Joint Photographic
Experts Group• A file format and
compression scheme.
• Emerging as a standard format for photos.
• Internet use.
JPG (Jpeg) FormatJPG (Jpeg) Format• “Lossy”
compression-• Reduces data
during save.• Data loss can be
controlled.• Can reduce file size
in a ratio between 10:1 and 20:1.
BMP FormatBMP Format• Microsoft native file
format
• PC system compatible– DOS– Windows– OS/2
• No MAC compatibility.
BMP FormatBMP Format• Photoshop encodes to
1, 4, 8, 24 bit color but .bmp can not support channels.
• No file space savings for photos with .bmp.
• - Try a JPG!
PIC (Pict) FormatPIC (Pict) Format• A MAC native file
format.• Not PC operating
system compatible.• Can do 24 bit color plus
an extra 8 bits.• Any MAC monitor can
display 32 bit PICT files
PICT FormatPICT Format• MAC system
format used to exchange data via clipboard.
GIF FormatGIF Format• Graphics Interchange
Format.
• Created by Compuserve to speed downloading of graphics.
• Limited to 256 colors.
• Compression format
GIF FormatGIF Format• Can be both
interlaced and non-interlaced
• Common Internet file format– 87– 89a (interlaced,
with one transparent color)
PNG FormatPNG Format• Portable Network
Graphics• New format targeted
for Internet use• Can support up to 48
bit color• Big compression
factor• Can support multiple
transparent colors
PSD FormatPSD Format• Photoshop native file
format.
• Supports all image types from line art to photos.
• Increasing compatibility with other software.
PSD FormatPSD Format• PSD can hold an
infinite amount of channels!
• Each layer can hold 24 channels.
• Infinite amount of layers are possible.
• Subject to available RAM!!!!
Multi-Channel to .GIFMulti-Channel to .GIF
Photoshop RGB
Indexed 256
.GIF
Convert to:
Save as:
PCX FormatPCX Format• From ZSoft Corp.• Many versions
exist.• Great for indexed,
grayscale and line art.
• Supports only one channel.
PCX FormatPCX Format• Photoshop only
supports PCX version 5!
• Convert .pcx to RGB to use most Photoshop tools.
• PC Paintbrush format.
Kodak Photo CD - PCDKodak Photo CD - PCD• Kodak format for
images stored on Kodak Photo CD.
• Uses YCC color model.
• Limited to five image sizes.
Kodak Photo CD - PCDKodak Photo CD - PCD• Photoshop
opens as a LAB color model.
• Photoshop can not save as a PhotoCD format.
Bitmapped FormatsBitmapped FormatsAnd PixelsAnd Pixels
Vector FormatsVector Formats• Images are a series
of pixels that are "turned on" based on a mathematical formula.
2(x + y)z
Vector FormatsVector Formats• Vector Formats are
basically defined by shapes and lines
• No more than 256 colors
• Clip Art
Vector FormatsVector Formats• Not resolution
dependent
• Infinitely scalable
• Not appropriate for photo realistic
• images
Common Vector File Common Vector File FormatsFormats
• WMF
• AI
• Post Script
• CGM
• Fonts
• DRW
• CIL
WMF FormatWMF Format• Windows Metafile
Format.
• Designed for easy exchange between Windows programs via clipboard.
• Common clipart format.
PostScript FormatPostScript Format• Developed by
Adobe Systems for typefaces.
• Expanded for many graphic elements.
• Encapsulated Post Script (.eps) is of this format.
PDF FormatPDF Format• Adobe Acrobat
file format.
• Portable Document Format
PDF FormatPDF Format• Integrates color,
graphics and text
• Searchable format
CGM FormatCGM Format• Computer Graphics
Metafile
• Most common DOS-based format
• Used by -– Harvard Graphics– Freelance Graphics– Others
CGM FormatCGM Format• Older versions of
format may not load cleanly into modern versions of software
• Can support very elaborate graphics
• A "schizophrenic" file format!
Vector FormatsVector FormatsAnd ShapesAnd Shapes
Software ChoicesSoftware Choices• Traditionally,
different software creates either bitmapped or vector art
• This is changing!
Software ChoicesSoftware Choices• For bitmapped,
names that include the words “Paint” or “Photo” indicates that the primary function of the software is to create and manipulate bitmapped formats
Software ChoicesSoftware Choices• For bitmapped,
names that include the words “Paint” or “Photo” indicates that the primary function of the software is to create and manipulate bitmapped formats
• Examples –– Adobe Photoshop– Deluxe Paint– Photoshop Elements– Macromedia Fireworks– Corel Photo-Paint– Paint Shop Pro
Software ChoicesSoftware Choices• For vector art,
names that include the words “Draw” or “Illustrator” indicates that the primary function of the software is to create and manipulate bitmapped formats
Software ChoicesSoftware Choices• For vector art,
names that include the words “Draw” or “Illustrator” indicates that the primary function of the software is to create and manipulate bitmapped formats
• Examples –– Adobe Illustrator – Corel DRAW– Microsoft Draw– Macromedia Freehand– Serif DrawPlus– Macromedia Flash
Software ChoicesSoftware Choices• Most modern
versions of bitmapped software also include draw tools
• Photoshop 6.0 now can create vector art.
Software ChoicesSoftware Choices• Adobe Acrobat,
desktop publishing, etc. software is friendly to both categories of graphic types
When to Use What When to Use What and When!?!? and When!?!?
What are the requirements of your output device?
When to Use What When to Use What and When!?!? and When!?!?
Image Quality File Size
When to Use What When to Use What and When!?!? and When!?!?
Image Quality File Size
Photo Image
Illustration
When to Use What When to Use What and When!?!? and When!?!?
Image Quality File Size
Photo Image
Illustration
Internet
Other ComputerDevices
Curriculum Content andCurriculum Content and
Activities created byActivities created by
Dr. Mark MortensenDr. Mark Mortensen
Dept. of Technology & Dept. of Technology & CognitionCognition
University of North TexasUniversity of North Texas