Quite often there is some confusion between PNG files and PDF files. People often think that a PNG is a vector file, where in fact it’s actually a raster image format.
A raster image is made up of tiny small squares or pixels. If you zoom in close you will be able to see the small pixels that make up the image. Other common raster image files are JPEG, GIF and Bitmap formats. Nowadays PNG files are the most preferred raster image file format used, especially for use on the web. PNG images can have transparent a background which means they can be placed over colour backgrounds, unlike a JPEG image.
A vector image is comprised of nodes and curves and based upon mathematical equations and doesn’t have any pixels. A vector image can be resized to any size and will always remain the same, with sharp edges and no blurriness. Try zooming in close and you will see that it remains sharp.
PDF files can contain both raster and vector images. Most logos that have been converted into vector format are often saved as PDF files, as PDFs can be opened by most other graphic software programs making PDF’s very portable and are widely used. Other common vector formats are:
AI (Native Adobe Illustrator format). Can also contain raster images.
EPS. EPS files can also contain raster images. This can cause confusion as people often think because they have an EPS file that it’s a vector image. But that’s not always the case as they find out when sending the file to a printing company where a vector image is needed.
SVG. (Scalable vector graphic). Also often used although not as common as a PDF or EPS file.
Vector Image Example
If you would like to see the difference between a PNG file and the PDF then please download the two example files below. If you zoom in to the PNG image you see it becomes pixelated. But try zooming in to the PDF image and you see it remains sharp. You may need to download Acrobat Reader if you don’t already have it installed.