This is mainly geared towards signmakers, if you've got a bitmap and would like to convert it to vector or line art for plotting, then bring it to us. We've got specialized software to convert any bitmap to a vector-base plotting file so that you will get a clean, smooth line everytime all the time.

Differences between raster and vector image formats. A computer screen generally displays 72 pixels per inch and most printers work with 600-2400 pixels per inch. The terms PPI, pixels/inch, DPI, dots/inch and SPI, samples/inch all are different terms for describing how the grid is laid out which is it's resolution.

The only difference between the terms are the devices being used. Scanners and monitors generally use PPI or SPI. Output devices use DPI. Drawing programs like Freehand, Corel Draw and Adobe Illustrator are vector based which use mathematical formulas to describe the shapes that make up an image. The advantage of using math to describe a shape is it doesn't have a set resolution. The shape will display/print at the highest resolution the output device supports. This is very different then raster images which have a fixed resolution.

Also fonts and therefore text is usually vector based. The way each format handles resolution is very important.

In Photoshop to achieve the highest quality you need to work at the correct resolution from the beginning, (e.g. 300 dpi). At a low resolution, each time you resize or alter the resolution the quality suffers. As you can see a raster based image at 72 dpi has fairly jagged edges. When increasing the size to 200% the resolution drops to 36 dpi and it is really jagged. On the other hand a vector based image looks much less jagged since the curves are defined mathematically and resizing the image has no effect on quality.