What are the best file formats for large-format printing?

There’s nothing quite like a large tray sign or big printed banner showing off your latest product or service. Get your design ready, send it to a digital printing company, and that’s it. Right?

The thing is, most people overlook one crucial detail: the file format.

It’s essential to use the right file format(s) to maintain quality on your large-format print projects. You need it to scale correctly and print without any issues that might otherwise affect your brand.

So, whether you’re thinking about JPEGs, PNGs, PDFs or vectors, here’s a guide to help you navigate the best file formats for your large format printing projects.

Raster vs vector

We’ll dive into the specific file formats in just a moment. But first, let’s talk about the basics. All graphics fit into one of two primary types, raster or vector.

• Raster images are based on pixels. They’re made up of tiny individual squares. Each of these squares is a particular colour. Since those squares are so small, the combination of tens of thousands of pixels forms a normal-looking image. Raster images include JPEGs, PNGs, TIFFs, etc. Rasters are great for photographs on your phone or laptop. Unfortunately, though, they lose quality when they scale up, because those pixels simply grow in size.
• Vector graphics are based on mathematical equations (vectors). Each line or colour area is defined by coordinates and curves. That means the computer doesn’t store the image as a set size. It actually redraws it every time you scale it. Thanks to these file formats, vectors don’t lose quality when enlarged, unlike raster images. Vectors include file types like AI, EPS and SVG. They’re perfect for anything that needs to stay sharp and smooth when you scale it up.

Print companies usually use a combination of both raster (images) and vector (logos and text) elements.

Best file formats for large format printing

Here are eight of the best file formats for a large-format printer. Remember: if you’re working with logos or graphics, you want a vector file. If you’re working with photos or other images, you need a raster. If you’re working on something like a flyer, combining images and graphics, you’ll need both.

Portable Document Format (PDF)

PDF [BK1] files are excellent for designs that combine text and images, such as brochures, posters or reports. They can handle both raster (pixel-based) and vector (scalable) elements, and that’s a fantastic benefit for most printing situations. When saved in high resolution (300 DPI) and using CMYK colour mode, PDFs are perfect for professional printing. To avoid any issues, make sure you embed all fonts in the file and that all images are high quality.

Print Exchange Format (PDF/X)

PDF/X files are a type of PDF created specifically for professional printing. Unlike standard PDFs, PDF/X formats (such as PDF/X-1a or PDF/X-4) restrict features that could cause issues during printing, like missing fonts or RGB colours. This makes them one of the most reliable options.

Encapsulated PostScript (EPS)

EPS files are a vector format. Because they’re vector-based, they can be scaled up or down as much as you like. However, EPS files aren’t great for detailed or photographic images, which can sometimes display incorrectly. EPS files are best used for clean, simple graphics.

Tagged Image File Format(TIFF)

TIFF files are ‘lossless’, meaning no image data is thrown away when the file is compressed. TIFFs can also include layers and transparency, which can be very handy during editing or printing. These files are often quite large, but you can apply LZW compression to reduce the size without affecting image quality. If you’re sending photos or detailed images to a professional printer, TIFF is usually the safest option. Printers sometimes also accept layered TIFF files, which can still be edited while maintaining quality.

Joint Photographic Experts Group (JPEG)

JPEG is one of the most common image formats. Most of the images on your phone and computer are likely JPEGs. This format works well for photographs or images with smooth colour transitions. For best results in large projects, save your JPEGs at a high quality (low compression) setting.

Photoshop Document (PSD)

PSD files are native to Adobe Photoshop and are perfect for projects that require detailed image editing. They can store multiple layers, masks, transparency and adjustment settings. Many printers accept PSD files because they make it easy to make last-minute changes without losing image quality. However, PSDs can become quite large, so it’s often best to flatten the file or export it as a print-ready format (like PDF or TIFF) immediately before sending it to your printer.

Adobe Illustrator (AI)

AI files are the native format used by Adobe Illustrator. They’re designed for vector-based artwork. Because AI files support layers, you can keep elements separate and adjust them as needed. Before sending your design to someone else, it’s best to convert any text into outlines and embed all linked images. This makes sure nothing goes missing or changes when the file is opened in a different program.

Scalable Vector Graphics (SVG)

Most printers don’t directly support SVG files, but they’re a great choice for vector workflows based on logos or other graphics. You’ll probably need to export your SVGs into PDF/X or EPS formats to send for the actual digital printing.

File formats to avoid for large-format printing

Some formats work well on screens but can cause significant issues when scaled up or sent to a large-format printer. If you’re preparing artwork for digital print or large format printing, avoid using the following file types, because you’ll quickly run into quality issues when they’re scaled up:

• PNG – PNGs are useful for web graphics and small-scale print, especially when you need transparency. They can be quite high quality, too. But unfortunately, they don’t support CMYK colour. For large-format print, they usually aren’t suitable unless exported at a very high resolution from the original design file.
• Low-res JPEGs – JPEGs themselves are fine if set up correctly. But if you’re using a version downloaded from a website or social media, it’s likely too compressed or too small for large-format printing. Always use the original high-res file when possible.
• GIF – this format is mainly used for simple web graphics and short animations. It only supports 256 colours, which is nowhere near enough for high-quality digital printing. It also compresses heavily, which can result in poor image quality.
• BMP – Bitmap files are uncompressed raster images. They tend to have huge file sizes without any real benefit in quality over TIFF or high-res JPEG. They’re not widely supported in professional printing.

Preparing your files for large-format printing

Here’s what to do to get your files ready for large-format printing. Consider the following aspects when you format and save your file:

• Resolution – for large prints viewed from a distance, a resolution of 150 to 200 DPI should be sufficient. You might get away with an even lower resolution, down to 75 DPI. If you’re expecting close-up viewing, aim for at least 300 DPI.
• Colour mode – always work in CMYK colour mode for print projects (instead of RGB). That’s the process used in printing.
• Bleed – include a bleed area (usually 3mm to 5mm) around your design to prevent any unprinted edges after trimming.
• File size – large format files can become quite large. Ensure your computer and software can handle the file size to avoid crashes or slowdowns.

How PB Signs can help you with large-format printing

It’s great to hear that you’re planning a large-format print project, and we’d be delighted to help. With years of experience designing and developing state-of-the-art print materials for companies large and small all around the UK, PB Signs is dedicated to helping you achieve whatever you need. Whether it’s help with the design, a quick guide on how to maximise file quality or our quick turnaround service, we’ve got you covered.

If you’re wondering how to choose the best file formats for large format printing, please don’t hesitate to reach out. We offer free consultations, and we can get your printed materials to you within a couple of days.

No matter if you’re after exterior wayfinding signage, printed floor tiles or a custom wallpaper print, we look forward to meeting and helping you.