Vector graphics are composed of lines and fill colors; most clip art falls into this category. The advantage of the vector format is that the graphic is fully scalable. You can enlarge it to 100 feet or reduce it to half an inch without losing the quality of your image. The vector graphic format uses mathematical calculations between the lines and makes adjustment in size based on the distance between the lines. Another advantage to this format is that the file sizes are much smaller than the typical raster graphic. The disadvantage is that the format uses 8-bit color. That means that there are only 256 colors available for fill and line colors.
Typically, vector graphics for the Windows platform are WMFs; the Mac uses EPSs. GIFs are what is known as a “cross-platform” graphic format. Both Windows-based PCs and Macs can open and view the GIF format.
You can edit vector graphics using the Edit Picture option in Word. To view tutorial see Easily Customize Clip Art using Microsoft Word.
Raster Graphics or Bitmaps
Raster graphics or bitmaps are composed of pixels. Photographs and complex clip art use the raster format. One of the advantages of the raster format is that it uses 24-bit color, meaning there are 16.7 million colors available to compose the format. Subtle gradients and contrasts are handled with ease. The file sizes are much larger than vector graphics. Another challenge is that enlarging a raster graphic too much causes the edges of the image to become ragged, known as “pixelation.” And, reducing the graphic too much makes the image unusable because the pixels are pushed together.
Windows uses the PNG format. Both Windows and Mac platforms use TIFFs and JPEGs. TIFFs are huge files, but maintain the integrity of the file better; use them for printing documents. JPEGs have a compression-system built in to make file sizes smaller; they’re used for viewing—websites, presentations, and computer software programs.
Note: The compression system built into JPEGs is faulty. Each time you save a JPEG, some pixels are lost in the process. It doesn’t take too many saves before the graphic degenerates to an unusable image.
You can edit raster graphics using the Format Picture option. You don’t have as many options available to edit this type of graphic in Word; however, you can adjust contrast and brightness; change to grayscale; change to black and white; or adjust the opacity to make watermarks.
Vector Graphic
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Photograph (Raster Graphic)
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Pixelated Raster Graphic
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