Learn More About Design: Vector vs Raster Graphics
05/15/09 10:23
I decided to add a few “Learn More About Design” articles for clients that want to learn more about what it is graphic designers do. There's a lot of terminology used in the field of graphic design and there are many processes that must be understood to ensure the best possible product is produced. The “Learn More About Design” articles will offer some explanations to those who ever wondered "CMYK? VECTOR? BLEED? CROPS? What does it all mean?"
This week’s topic:
“Vector vs Raster Graphics (and what the heck does that even mean?)”
All graphics fall into two main catagories, Vector or Raster.
Vector graphics use geometrical formulas to represent images and objects, such as rectangles, circles, or complex curves. Because vector graphics are defined as shapes, and not pixels, the files are highly compressed and do not lose resolution even when the magnification is increased or decreased. For this reason, logos are created as vector graphics so they can be used at many different sizes, from very large banners to small business cards.
Advantages of vector graphics include scaleability, small file sizes and easy color separations, all weaknesses of raster images (photos, etc).
Likewise, the disadvantage is that it’s difficult to create a photo realistic image with a vector graphic.
Some common programs that create vector based graphics include Adobe Illustrator, Corel Draw, and Freehand (.ai, .eps files)
Raster images are those made up of pixels, such as photographs or files created using Photoshop (.psd, .tif, .jpg, .gif).
The advantage of a raster graphic is a photo-realistic quality. No other file type can match a raster graphic for realism.
One disadvantage is file size. These files have a larger file size as compared to vector images, sometimes significantly so. Another disadvantage is a resolution/scaleability issue. If you could stretch your raster image three times its original size you end up with pixels that are three times bigger, making your image look pixeled or blurry. Because of this, a raster image that looks OK when small will look very rough and jagged when it is blown up. This is why using photographs from a website does not work well for print. Blowing up the web graphics to the higher resolution just results in very blurry artwork. This is not the case with vector files.
So knowing how you want to use a graphic before it is created is an important step in deciding what software to use.
As a general rule, logos should always be created as a vector graphic using a programs such as Adobe Illustrator instead of Photoshop (photoshop files are raster and therefore will become blurry and pixeled if the logo needs to be scaled to a size larger than it was originally created).
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Diane Foley
Owner and Lead Designer of The Visual Sense
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This week’s topic:
“Vector vs Raster Graphics (and what the heck does that even mean?)”
All graphics fall into two main catagories, Vector or Raster.
Vector graphics use geometrical formulas to represent images and objects, such as rectangles, circles, or complex curves. Because vector graphics are defined as shapes, and not pixels, the files are highly compressed and do not lose resolution even when the magnification is increased or decreased. For this reason, logos are created as vector graphics so they can be used at many different sizes, from very large banners to small business cards.
Advantages of vector graphics include scaleability, small file sizes and easy color separations, all weaknesses of raster images (photos, etc).
Likewise, the disadvantage is that it’s difficult to create a photo realistic image with a vector graphic.
Some common programs that create vector based graphics include Adobe Illustrator, Corel Draw, and Freehand (.ai, .eps files)
Raster images are those made up of pixels, such as photographs or files created using Photoshop (.psd, .tif, .jpg, .gif).
The advantage of a raster graphic is a photo-realistic quality. No other file type can match a raster graphic for realism.
One disadvantage is file size. These files have a larger file size as compared to vector images, sometimes significantly so. Another disadvantage is a resolution/scaleability issue. If you could stretch your raster image three times its original size you end up with pixels that are three times bigger, making your image look pixeled or blurry. Because of this, a raster image that looks OK when small will look very rough and jagged when it is blown up. This is why using photographs from a website does not work well for print. Blowing up the web graphics to the higher resolution just results in very blurry artwork. This is not the case with vector files.
So knowing how you want to use a graphic before it is created is an important step in deciding what software to use.
As a general rule, logos should always be created as a vector graphic using a programs such as Adobe Illustrator instead of Photoshop (photoshop files are raster and therefore will become blurry and pixeled if the logo needs to be scaled to a size larger than it was originally created).
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Diane Foley
Owner and Lead Designer of The Visual Sense
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