You get the picture...

What's in a picture?

Digital CameraImage resolution and associated abbreviations such as 'dpi' (dots per inch) often confuse a lot of people. This page explains what resolution is and how it needs to be taken into account when creating layouts or printing pictures.

The resolution of the original image is the critical factor. People sometimes make the mistake of thinking they can take a low resolution image, put it in Photoshop, and then change the resolution to 300dpi to make it a high resolution image.

While Photoshop can usually effectively double the resolution of an image using interpolation, that's about the limit. Changing a low resolution pixelated original image in Photoshop to 300dpi will just result in a very large file size 300dpi image that is still pixelated. You need to start with a high resolution original, and you also need to create your original Photoshop files in high resolution.

When an image is sent to a certain output device, such as a printer or a monitor, its resolution becomes important because each device or medium needs a certain base resolution to reproduce the image with the best possible quality. See our handy guide below for more.

Resolution Guide

  • PC Monitor
     
    Most computer screens have a resolution of around 100 dpi.
     
    The resolution of digital cameras far exceeds that of monitors at this point in time and the resolution of television screens is usually even lower than that of computer screens.
  • For images printed on good quality paper using an offset press, the general rule is that the image resolution needs to be twice the screen ruling used to print the job. Magazines are typically printed using a 150 or 175 lpi screen ruling. This means images need to be 300 dpi.

    Please note that a slightly lower resolution such as 220 to 250 dpi is also perfectly acceptable for most people. For high quality jobs such as art books or for images containing critical patterns such as brick walls or clothing with a pattern in it, a higher resolution is sometimes recommended by the printer. Typically 400 dpi is used for such images.

  • newspaper

    Newspapers are printed at a higher speed on lower quality paper. This means the resolution requirements are not as high as those for magazines.

    Typically a resolution of 200 to 250 dpi is considered sufficient. For line art images, 400 to 600 dpi is recommended.

  • Billboard

    The larger a picture gets printed, the lower its resolution needs to be. The main reason behind this is that the viewing distance also increases.

    For large billboards, 30 dpi is often sufficient – which means that a lot of digital cameras are perfectly capable of generating such files.

  • Usually 250 dpi is considered the optimum resolution for printing high quality photos. Don’t be fooled by the fact that a photo printer has a much larger resolution, such as 720 or 1440 dpi. The printer may be able to print very small dots but it can only accurately reproduce colors by combining a large number of dots to emulate various tints. That is why a 250 dpi image offers perfect output quality on a 1000+ dpi printer.

    The professional photo lab equipment used to print thousands of images per day also has a higher resolution, typically 300 to 600 dpi. The same rule applies for pictures printed using such a machine: 200 to 250 dpi offers excellent quality.