Pixels and vector: what’s the difference?
We want nothing more than having your printed product look fantastic! But how can you check if your artwork is suitable for printing? We’ll explain what you need to look for when you’re designing your artwork.
There are two types of graphic files: pixel and vector based graphics. Pixel based graphics are made up of little squares (pixels) which can be seen when you zoom in on your image. The quality of these images is based on the resolution of the image. The resolution is shown in DPI (Dots Per Inch). When we make the image twice as big, then the DPI is halved, making them visible. If you’re enlarging an image to be printed (which is needed for large prints such as flags, etc.) and the print looks blurry if the image is not high resolution.
Vector graphics are mapped out using mathematical equations which calculate where the edges of the shapes sit in relation to one another and also the colour, type of line and fill. These lines will always keep their shape regardless of how big or little you resize them. This means that no pixels will show when you zoom in. It doesn’t matter how large you make the graphic, the quality will stay the same.
How can I recognize a pixel or vector graphic?
Vector graphics are usually made in Adobe Illustrator and usually have one of the following file extensions: AI, ESP or PDF. Please note that not all files labelled like this means they are vector files, especially PDF files.. Pixel graphics are often made in Adobe Photoshop and have these file extensions: JPG, TIFF, PSD or BMP.
Sometimes people send us artwork which they think is a vector based graphic but turns out to be a pixel based graphic. Often what has happened is that the pixel image (e.g. JPG) was placed in an Illustrator PDF file or saved in Photoshop as and EPS file. This however, doesn’t make it a vector based graphic.
Test it yourself!
Would you like to check if your artwork is a vector or pixel graphic? Zoom in on the file. If the image stays clear and sharp, then it’s a vector image. Do the pixels become visible? Then it’s a pixel based graphic.
How do I know if the resolution is high enough?
Previously we explained the difference between pixel and vector based images. But how do you know if the resolution of your images/artwork is high enough? Below you'll find a few ways that can help you find the answer.
Professional design programs have an option to show the resolution of the file. We would like to have a resolution of 300DPI when the file is displayed as the actual size in your design program. This is the resolution needed to have a sharp printed product. Large products such as posters, banners and roll-up banners will be viewed from far away so a resolution of 150DPI is sufficient.
Be careful not to assume that your resolution is sufficient if the program says that your artwork has a resolution of 300DPI. Sometimes logos or text that are used in your artwork may originally be lower quality. To prevent this, we suggest to always use original image files and not images from the internet. Always try to refrain from using programs such as Paint (pro) or Picasa as they automatically resize your files to 72DPI which will give images, logo or text a blurry look.
You can easily see if your image has sufficient resolution by zooming in to 200%. Can’t see the difference between your brother and sister in your family photo? ☺ Then that’s a clear indication that your artwork’s resolution is too low. For business cards, pens and other products that you view from close by, you need to view the artwork at 600%. Large items such as posters, banners and other products that you would look at from ‘over’ a metre away, you can check the image at 50%.