The Scoop on Vector and Bitmap Images
Vector and bitmap images are the two major graphic types. Both types are made up of many individual objects, and both respond differently when enlarged and/or reduced to produce different image sizes.
Vector and bitmap files are both very workable, however vector files can change sizes easily without sacrificing quality, using the original formats. Also, vector images can be output at the highest quality in any scale because they are made of lines and panels, rather than pixels or dots. They are resolution independent and the common formats are .eps, .ai and .pdf, which are all commonly available in most graphics programs.
A bitmap image (also called a raster image) is made up of pixels (or ‘dots’). The number of pixels in one square inch of an image is called the dpi (dots per inch) and is known as the resolution of the image. Quite simply, the larger number of dots you have in your image, the higher quality the final product will be.
Bitmap images will lose that quality when they are re-sized from their original specs, and must always be created with consideration for their intended use. Ideally, these images should be built at 150 dpi if they are at the actual finished size. You can build the bitmap files at a smaller proportional size than the final usage size, but it is imperative to increase the resolution accordingly. For instance, if you build your file at a ratio of one inch to one foot, you should build the file at 300 dpi. To do so, you would build a 2” x 2” file at 300 dpi to print a resulting 2’ x 2’ image at 150 dpi. Common bitmap-based formats are .jpeg, .jpg, .gif, .tiff, .png, .pict and .bmp.
Although vector image is the generally preferred format for submitting artwork, it is not as common for non-designers and bitmap images at the correct resolution can be substituted. We know that this information can be overwhelming to our customers, so if you have any questions or concerns about your files, just give us a call at 651 633-2233! At Signsational Graphics, we are happy to assist you in every step of your signage project, ensuring an artfully executed, high quality final product.