Artwork can be the correct size and still produce a blurry print. The page dimensions tell the printer how large the design should be. They do not tell you whether the photographs and other images contain enough detail for that size.
This came up during a recent banner job. The artwork was supplied at the correct dimensions, and we replaced a logo with a vector version to give it clean edges. The background images still lacked detail at banner size. Improving the logo had not changed those separate images.
The lesson for us was to make the remaining image-quality limitation clearer before approval. If you are arranging print, ask for the images to be checked at the finished size, with any concerns explained alongside the proof.
Why the logo can be sharp while the background is soft
A vector logo uses shapes and lines that can be enlarged without the edges becoming pixelated. A photograph is made from a fixed number of tiny squares called pixels. When you stretch it over a larger area, those same pixels have to cover more space.
One PDF can contain both. Its text and logo may look crisp while a background photograph becomes soft or blocky. Saving a small photograph inside a PDF, or placing it in a vector design file, does not turn it into vector artwork.
A useful check looks at each image separately. It also checks the exported PDF, because export settings can reduce image detail even when the original files were suitable.
What happens when you make an image bigger?
Take an image that is 3,000 pixels wide. Printed at 25cm wide, it has about 300 pixels per inch. At one metre wide, it has about 75. The file has not changed; the same detail is spread across four times the width.
Four times the width means a quarter of the image detail per inch. Figures are rounded; this is a size comparison, not a print proof.
You may hear this called effective resolution: the amount of image detail available at the size it will actually be printed. It is more useful than a “300 dpi” label viewed without the intended print dimensions.
Pixels per inch, or ppi, describes the image. Dots per inch, or dpi, describes the printer's output, although artwork specifications often use “dpi” for both. You do not need to untangle the terminology yourself. Tell your print partner the finished dimensions and ask whether each image is suitable at that size.
Does everything need to be 300ppi?
Around 300ppi is a common target for photographs in print that people hold and read close up. Large-format requirements vary by product, material and viewing distance. A banner behind a stand and a brochure in someone's hand are viewed differently.
Follow the specification for the product being ordered. There is no single lower resolution that is suitable for every banner, and an image that starts out blurred can remain blurred even when its pixel count meets the specification.
If artwork is supplied at a reduced scale, the resolution must also allow for enlargement to the finished size. Your designer or print partner can check this against the product template.
Will changing the dpi or enlarging the image fix it?
Changing a resolution setting without adding pixels does not create detail. Software can add pixels through a process called resampling, but ordinary enlargement estimates them from the information already there. It cannot recover detail that the original image never captured.
Upscaling tools can sometimes make an image more usable. The result still needs checking, particularly around faces, small lettering and product details. For a logo, the original vector file is usually the better starting point. For a photograph, first look for the original camera file or the largest licensed download.
Other practical options include using the image at a smaller size, replacing it, or changing the layout so it does not have to fill the banner.
What to send for an artwork check
You can help your designer or print partner give you a useful answer by sending:
- The finished dimensions and product. Include the exact banner, display or printed item you plan to order, and its template if you have one.
- The original images. Send the largest available files rather than screenshots, website copies or images pasted into a document. Include permission to use them where relevant.
- The original logo artwork. A vector PDF, SVG, EPS or Illustrator file may be suitable, but the contents need checking. The filename alone does not establish that it contains vector artwork.
- The editable design and exported PDF. Supply linked images and fonts where your licence permits, or an agreed packaged file.
- How and where it will be seen. Explain whether people will read it close up, see it across a room, or both. Include the required delivery date so there is time to resolve problems.
Ask what the proof actually confirms
A PDF fitted to a laptop screen can hide problems that become visible on a large print. Use it to check wording, layout and placement, but ask separately about image quality at the finished size.
If an image is borderline, ask which part is affected and what the alternatives are. A full-size detail crop can help the discussion. For a critical job, ask whether a physical sample is available, what it will show, and what it adds to the cost and timetable.
Before approving, you should know which version is going to print and understand any remaining limitations. Keep that explanation with the approval record.
Through our managed print service, we help check supplied artwork and explain what needs attention before production. Tell us what you are printing and what files you have. We will agree any artwork changes and their cost with you before starting.
Further reading
For more detail, Adobe explains image size and resolution and vector and raster artwork. For the rest of the job, see our guide to planning exhibition print.
Planning a print job?
Tell us what you need to print, when you need it and what artwork you have. Andy will suggest a practical next step.