What is the difference between pixels and vectors?
When you’re working on the layout of your thesis, you’ll no doubt come across terms such as pixels and vectors against. At Persoonlijk Proefschrift, we work with all types of images; we also always ask for the images to be provided separately to be supplied. But what do these terms actually mean, and why is it important to know the difference? Let’s explain it in simple terms.
Pixels
Let’s start with the better-known of the two: pixels. Pixel images, also known as bitmap images, consist of thousands of tiny dots (pixels) which together form an image. The quality of these images depends on the resolution, expressed in DPI (dots per inch). The higher the resolution, the sharper the image. Please note: when you enlarge a pixel image, the pixels are stretched, which reduces the quality.
File formats that use pixels: .jpg, .png, .tiff, .bmp, .psd
Vectors
Unlike pixel images, vector images are made up of lines and shapes that remain crystal-clear at any size. These files are ideal for graphic elements such as logos, line drawings and diagrams. For the best print quality, we recommend using vector files wherever possible.
File formats that use vectors: .ai, .eps, .svg, .pdf (please note: not every PDF is automatically a vector file)
How can you tell the difference?
Zoom in: Zoom in on the image. Does it remain sharp? If so, it’s probably a vector file. Does it become blurry or blocky? If so, you’re looking at a pixel image.
File type: Check the file extension. As mentioned above, the extensions often indicate whether the file is a raster or vector file.
Pixels vs Vectors
Pixel images consist of a fixed number of dots. If you enlarge such an image, you also enlarge those dots. Imagine this: you have an image measuring 500 by 500 pixels. On a screen measuring 50 by 50 cm, each pixel is then approximately 1 square millimetre. But if you were to display that same image on a 5 by 5 metre billboard, each pixel would suddenly be 1 square centimetre in size. You would then clearly see the blocky structure – the image becomes blurry or ‘grainy’. That is why pixel-based images quickly appear blurred if you stretch them too much, especially at low resolutions.
Vector images In contrast, they are based on mathematical formulas, not on a grid of dots. Lines, shapes and colours are described using coordinates and ratios. This means you can enlarge or reduce a vector file endlessly without any loss of quality. Whether you put it on a business card or on a wall ten metres wide – it will always remain razor-sharp.
