Vector vs. Raster

1
Vector vs. Raster

• Whats the difference between vector and raster
  file formats?
• The real difference between the two formats is
  how they are used.

http//www.logoshed.net/store/docs/8/raster_vs_vec
tor/
2
Raster artwork (also known as bitmaps)

• are composed of lots of small dots. This lends
  itself to photographic or artistic effects
  because color gradations can be made very smooth
  in a bitmap format. However, bitmap images lose
  their clarity when they are increased in size
  because the dots get bigger. Take an image that's
  10 pixels wide by 10 pixels high, stretch it to
  100 x 100 pixels and it looks like it's made of
  big squares.
• Adobe Photoshop, the industry standard for
  digital photo editing, allows users to open and
  edit both formats however, when a file is opened
  in Photoshop, it can only be edited and saved as
  a raster format file. All vector images (such as
  Illustrator AI and EPS files) will be rasterized,
  that is, converted into the small dots that make
  up the raster format.?

File Formats

• Graphic Interchange Format (.GIF)
• Joint Photographers Expert Group (.JPEG, .JPG)
• Tagged Image File Format (.TIFF, .TIF)
• Encapuslated PostScript (.EPS)

3
Vector artwork (sometimes called line art)

• this kind of artwork is made up of lines and
  filled areas only, which are mathematically drawn
  and calculated (hence the term vector) by the
  software you use. They can be stretched in size
  without losing any clarity or sharpness. Because
  of their mathematical origins, vector images are
  readily scalable without distortion.
• For vector image editing, use either Adobe
  Illustrator or Macromedia Freehand. Either
  program will also allow users to import raster
  images into their vector files.

File Formats

• Illustrator (.AI)
• Encapuslated PostScript (.EPS)
• PostScript (.PS)
• Windows Meta File (.WMF)
• Flash Movie (.FLA, .SWF)?

Both Illustrator AI and EPS formats allow users
to place raster images within a vector file. The
raster image is not converted to vector format
rather it is simply embedded in the vector file,
and is rendered in raster format.
4
Vector/Raster When and Why?
Vector programs make short work of manipulated
text and any solid color work.

• If you are working with mainly solid color
  objects, manipulated text or many small objects,
  the clear answer is that a VECTOR program will
  save you time.
• If you are working with complicated drop shadows,
  or other 3D effects, texture or photographs,
  RASTER is the correct choice.

For photo work, only a raster program makes sense.
http//www.webreference.com/graphics/column31/4.ht
ml
5
TIFF to the rescue

• Many times vector programs do not have the power
  to rasterize images with good results
• TIF is a raster program, widely used in print
  work, that supports 24 bit color without
  degrading quality. You can expect better results
  with this format than with uncompressed JPG
  files.
• Export as TIF and then open in a raster program
  to convert to GIF or JPG.

Exported directly to 72 dpi JPG
Exported at 300 dpi in TIFF format. Opened in
Photoshop to reduce resolution and optimize
9.63kb
6
Going the other way - TRACE

• When you have learned to work well with a vector
  program, and are comfortable drawing and editing
  nodes in paths, you can import the raster image
  and place it on its own layer.
• Reduce the opacity of the layer to fade the image
  back (if available), or draw a semitransparent
  white rectangle over the image.
• Lock the layer containing the image to be traced.
  
• Trace the objects on a new layer.

• Tracing partially completed. The blue outline
  shows one area that has been traced this area
  is now a vector object.

Note Incorporate the raster image into the
vector image if you are not going to need to
resize the image.