Artwork: Image Resolution Explained

What does image resolution mean?

In printing, image resolution refers to the amount of detail contained within an image. It is usually described in terms of dots per inch (DPI), which indicates how many individual dots of ink are used to reproduce the image over a given area.

Higher resolution images contain more detail and can be printed more clearly at larger sizes. Lower resolution images contain less information and can appear blurred or blocky when printed.

Screen images vs printed images

Images displayed on screens are designed to be viewed using light rather than ink. As a result, screen images typically use a lower resolution than images intended for print.

An image that looks clear on a monitor may not contain enough detail to print well, especially if it is enlarged. This difference between screen and print resolution is one of the most common sources of confusion.

Recommended resolution for print

For most printed books and documents, images should be supplied at a resolution of 300 DPI at their final printed size.

This ensures that photographs and graphics reproduce cleanly without visible pixelation. Images supplied at a lower resolution may be acceptable at smaller sizes but can quickly degrade if scaled up.

Scaling images and effective resolution

Increasing the size of an image within a layout reduces its effective resolution. For example, an image that is 300 DPI at a small size may drop below acceptable resolution if it is enlarged significantly.

This is why simply increasing image size in design software does not improve quality. The original image must contain enough detail to support the intended print size.

Checking effective resolution before exporting a final PDF helps avoid this issue.

Common sources of low-resolution images

Many low-resolution images come from:

• Websites and social media

• Screenshots

• Compressed email attachments

• Images copied from documents or presentations

These images are usually optimised for screen use and are not suitable for print without replacement or redesign.

Line art and graphics

Not all artwork behaves the same way.

Photographs rely on resolution, while vector graphics such as logos, icons, and illustrations are resolution-independent. Vector artwork can be scaled without losing quality and is preferred for logos and text-based graphics.

Where possible, logos and graphic elements should be supplied in vector format rather than as images.

Checking image resolution before printing

Most professional design software allows you to check the resolution of images placed in a document.

Reviewing image resolution before exporting a final PDF helps identify any problem areas early. This is especially important for covers and full-page images, where quality is most noticeable.

Image resolution and paper choice

Paper type can influence how resolution is perceived.

Highly detailed images may appear sharper on coated papers, while uncoated papers can soften fine detail slightly due to ink absorption. This doesn’t change the required resolution but can affect the final appearance.

Understanding this interaction helps set realistic expectations.

What happens if resolution is too low?

If images are supplied at too low a resolution, the options are limited. The image may need to be replaced, reduced in size, or accepted as-is with a potential reduction in quality.

Addressing resolution issues before printing begins avoids difficult decisions later in the process.

If you’re unsure

If you’re not confident about the resolution of your images, you can still submit your files.

We’ll review them as part of the pre-production checks and flag any areas that may affect print quality before anything goes to press.

Related guides

You may also find these articles helpful:

• Supplying Print-Ready PDF Files

• CMYK Colour Setup Explained

• Trim and Margins Explained

• Paper Types Explained