Setting Up Design Files for Large Format Printing
Tips to Avoid Blurry Images or Artwork
You need a poster, a banner, a schematic – and you’ve sent the design file to your large format printer, but you get an email back: “Your image must be 300 DPI or else it will be pixelated.” Sound familiar? If so, let’s break down what exactly your printer’s telling you – and what you need to consider to get the absolute best quality from your large format prints.
Designing to Scale
First off, the printing process will be much smoother, and less at-risk for mistakes, if you set your file up at full size. That being said, every graphic design programs has a different size limit. InDesign’s maximum dimensions are 216 inches (18 feet); Illustrator’s are 227.5 inches (19 feet) and PowerPoint’s are 56 inches (4.5 feet). If the final output size is greater than the design program’s maximum dimensions, you’ll have to design your file at a percentage of the final print size – either 25%, 50% or 75%. The percentage you use depends on the final size. Your printer will scale the file proportionately larger to meet the final print size, so communicate your scale and print size with your printer to make sure you’re on the same page. Miscommunication and mistakes can cause quality to slip in the final print.
When you’re scaling, you want to make sure your scale doesn’t tamper with your image quality. There are two types of images – raster and vector. This is where that warning about pixelation comes into play. Raster images are composed of pixels, those tiny squares that appear when zooming in too far – think old arcade games – P for Pac-Man. Pixelation refers to the blurriness of a raster image when it is viewed at too high a magnification – like a large format print. When scaled up, raster images can blur depending on the resolution, especially if you are designing at a percentage of the final print piece. JPG, GIF and TIFF are examples of raster file formats.
Vector images, such as EPS and AI are what we recommend for large format printing. Using mathematical calculations that form lines and shapes from one point to another, vector images don’t pixelate because the equation recalculates to accommodate zoom. Vector images can be scaled limitlessly, which makes them perfect for a large format.
Your printer warns about pixelation, but they also mention DPI. That’s resolution. Dots per Inch (DPI) are the number of individual dots that can be placed in a line within the span of 1 inch. Pixels per Inch (PPI) is the same measurement but is used in reference to raster images. We recommended that all images be 300 DPI at the final size of the piece. While 150 DPI can work for some large format pieces, 300 DPI is the preferred image size. This doesn’t mean you cannot include images that are lower DPI. Just be sure to again let your printer know – that way, they can make recommendations to get you the best quality. Communication is the key.
Your scale, image type, and resolution are compatible to large scale printing, but you want your quality color too. When setting up color, make sure your images and other artwork are CMYK (Cyan Magenta Yellow Key) for print. Also make sure the links across all platforms are the same IE same Pantone color from Illustrator to Indesign. Setting up CC libraries can help make sure the color is the same across the board.
You also need to take margins into account; often times margins should be larger for large format printing. The standard margin for smaller pieces are ¼ inch. However, when scaled up for large format, this looks too cramped. You’ll typically want to increase your margin to 1.5-2 inches; within that range you can use your best judgment based on the size of your project and the look that you’re going for. Also – note that the standard bleed of ⅛ inch is sufficient for large format printing and does not need to be increased.
Working at a scaled percentage
Finally, you need to revisit the scale of your project. If the project you’re printing is going to end up larger than your design program’s maximum dimensions, you’ll have to work on a scaled down file.
The maximum dimension in InDesign is 216 inches in either direction. For Illustrator, maximum dimensions are a little larger, 227.5 inches in either width or height. In addition, there is a maximum file output increase of 400%, meaning you can’t scale anything down smaller than 25% of the final size.
While working on your images in Photoshop, make them half the scale and double the resolution, so a 120 x 80 inch photo at 100 ppi becomes a 60 x 40 inch photo at 200 ppi. When you link the images into your banner in InDesign or Illustrator, you will need this half-size image because your document is half the final size.
One more thing! Before you save your final file for printing preparation, check your preflight channel to make sure all of your links and fonts are in order. If there is a red dot in the preflight panel, that means there is an error. Make sure there are no errors and the dot is green before saving and exporting your file. After that’s done and you’ve reviewed the rest of what we’ve covered, your file is ready to be sent to the printer for a quality final product – polished instead of pixelated.