File Formats and Vector File Formats and Vector GraphicsGraphics

File TypesFile Types

Images and data are Images and data are stored in files. stored in files.

Each software application Each software application uses different native file uses different native file types and file formats.types and file formats.

Each Each file typefile type has specific has specific uses and restrictionsuses and restrictions

Bitmap Images and Vector Bitmap Images and Vector GraphicsGraphics

A A bitmap imagebitmap image is stored as is stored as individual square pixels, each individual square pixels, each defined as a specific color.defined as a specific color.

The number of The number of pixels per inch pixels per inch (ppi)(ppi) is a measure of the image is a measure of the image resolution when displayed on resolution when displayed on the screen.the screen.

A bitmap file contains an image A bitmap file contains an image in one of various bitmap in one of various bitmap formats, such as TIFF, GIF, JPEG formats, such as TIFF, GIF, JPEG and BMP.and BMP.

The most common file The most common file formats for bitmap images formats for bitmap images are are JPEGJPEG and and GIFGIF files. files.

A bitmap file always A bitmap file always contains contains RGBRGB data. data.

Bit mapped images can Bit mapped images can get “jaggies” when the get “jaggies” when the image is enlarged because image is enlarged because the image is composed of the image is composed of colored square pixels.colored square pixels.

Vector graphicsVector graphics represents represents images as mathematical images as mathematical formulas that define all the formulas that define all the shapes in an image.shapes in an image.

A vector graphic image is A vector graphic image is composed of composed of lines lines and a fewand a few control pointscontrol points that are that are connected using Bezier curves.connected using Bezier curves.

Vector images are more Vector images are more flexible than bit-mapped flexible than bit-mapped graphics.graphics.

Vector Graphics ImageVector Graphics Image

Vector graphic images Vector graphic images retainretain their their sharpnesssharpness and and shapeshape even when even when scaled to different sizes.scaled to different sizes.

Vector images are Vector images are commonly created and commonly created and used in Adobe used in Adobe Illustrator, Corel Draw Illustrator, Corel Draw and Macromedia/Adobe and Macromedia/Adobe Freehand.Freehand.

JPEG – Joint Photographic JPEG – Joint Photographic Expert GroupExpert Group

Used primarily for photographs, Used primarily for photographs, graphic images.graphic images.Most common format to store and Most common format to store and transmit images on the web.transmit images on the web.Supported by all browsers.Supported by all browsers.

File saved in JPEG format has a File saved in JPEG format has a compression algorithm applied to compression algorithm applied to the image, throwing out bits (but the image, throwing out bits (but we do not notice the differences).we do not notice the differences).Each time an image is saved, more Each time an image is saved, more bits are lost. Save JPEG file only bits are lost. Save JPEG file only ONCE in image editing programs.ONCE in image editing programs.

Standard in Standard in lossylossy compression. compression.Does not convert well to GIF Does not convert well to GIF format.format.

GIF – Graphical Information GIF – Graphical Information FormatFormat

Originally created by Compuserve Originally created by Compuserve to send images across the internet.to send images across the internet.

No de facto file format at the No de facto file format at the beginning of the web, GIF became beginning of the web, GIF became the standard for file transmission the standard for file transmission since it included a compression since it included a compression factor for easy file transmission.factor for easy file transmission.

Limited to high contrast images, Limited to high contrast images, simple images, line drawings, text, simple images, line drawings, text, logos, clip art, and lots of single logos, clip art, and lots of single color areas.color areas.

LossyLossy compression. Saves compression. Saves transparent background.transparent background.

PNG – Portable Network PNG – Portable Network GraphicsGraphics

LosslessLossless compression, compression, designed primarily for use in designed primarily for use in Flash, Corel Draw, MSPaint, and Flash, Corel Draw, MSPaint, and Fireworks.Fireworks.

Designed to replace GIF and Designed to replace GIF and TIFF, but did not happen.TIFF, but did not happen.

Better compression than GIF.Better compression than GIF.

Supports transparency in an Supports transparency in an image (in other formats image (in other formats transparencies turn opaque).transparencies turn opaque).

TIFF – Tagged Image File TIFF – Tagged Image File FormatFormat

Used in InDesign or Quark Used in InDesign or Quark production images.production images.

Most popular for prepress Most popular for prepress images.images.

Platform independent; supported Platform independent; supported by numerous image processing by numerous image processing applications.applications.

Standard in document imaging; Standard in document imaging; most accepted file type for most accepted file type for printing.printing.

Cannot be embedded into Cannot be embedded into a web page.a web page.

Owned by Aldus which later Owned by Aldus which later merged with Adobe.merged with Adobe.

LosslessLossless (resulting in larger (resulting in larger files); some versions of TIFF files); some versions of TIFF have compression algorithms have compression algorithms applied to final image.applied to final image.

No provision for storing No provision for storing vector graphics or animation.vector graphics or animation.

EPS – Encapsulated EPS – Encapsulated Postscript FilePostscript File

InDesign or Quark production InDesign or Quark production images.images.Used in print production Used in print production applications.applications.Files are very large.Files are very large.

Takes lots of time to render Takes lots of time to render image.image.Image in EPS cannot be Image in EPS cannot be modified.modified.

Image preview before printing Image preview before printing is shown as JPEG file.is shown as JPEG file.