​The Complete Guide to Creating Press Ready Print Files

​Even the best designers break out in a cold sweat when it comes time to send a project to a printer. There are a ton of moving parts, checklists and details to keep in mind when it comes to getting your project ready for commercial printing. This guide will cover the technical do's and dont's, give you tips and best practices and walk you through how to take a project from your computer to the printing press.

How to Plan For Perfect Color Printing

One of the most common issues with professional printing is sending your printer graphics files that is in the wrong color space. Here's what you need to remember about color before you send your file to your printer.

CMYK not RGB

Your computer uses a color space called RGB to produce the colors you see on your screen. A printing press uses a color space called CMYK to produce similar colors using just four colors of ink: cyan, magenta, yellow and black, also know as 4 color process. When you send your files to a commercial printer, they must be in the CYMK color space.

This is so important that we have a whole page dedicated to RGB vs CMYK color space if you want to learn more.

Here's how you change your color space in InDesign: When you create a new document, the color space changes based on your intent.

InDesign document settings

You can also change the color space in t

InDesign color panel CMYK setting

Spot Colors

Most of the colors produced in color printing are created by blending just 4 colors of ink: cyan, magenta, yellow and black. But sometimes you need a very specific color. Despite all of the advanced techniques and technology at a professional printer, matching the exact color from printer to printer and even from one order to the next can be a challenge. Consistent color-matching is what separates good printers from great ones.

When you need a very exact color, such as Coca-Cola's trademarked red or John Deere's famous green, you'll need to use a spot color. A spot color is not created by mixing other types of ink, but rather it is made to order for the project at hand. This also means the printer must make an additional plate for the spot color, which usually makes using a spot color more expensive. If you have to use a spot color, you're likely using a color from the Pantone Matching System. It is a commonly used system of spot colors that helps press operators achieve the exact same shade, every time. Find a Pantone Color here.

Speciality inks like metallics, neons and unique colors will also have to be run as spot colors. Spot colors can be expensive for short run orders, but become more economical if you're doing larger quantities using offset printing.

Viewing spot colors that are blended with other colors, or are somewhat transparent, can be a problem in your page layout program. Make use of Overprint Preview when you're working with spot colors.

Planning Image Quality for Professional Printing

Low quality and low resolution images produce terrible, ugly, hideous printing but many people don't understand the relationship between quality and resolution. You must plan for your final output at the beginning of your design, otherwise you'll be left with an unusable final product.

Print will always look better with higher resolution images. Let's get clear on what we mean by resolution.

Image resolution is how much data is in a digital image, it is directly related to how many pixels are in the image. When you print an image, you must transfer that data into dots per inch (DPI) which determines the image quality of a printed piece. Usually, 300 DPI is what you'll need. Most images on your computer are not at 300 DPI, but 72 DPI. This is because 72 DPI looks good on most computers and the files are much easier for the computer to store and display. Be sure to check your images for print quality and insure that they are 300 DPI or higher.

How to Resample Images for Printing

Resizing images can lead to problems when they are printed because the resolution can be unintentionally changed.

When you resample an image, you are changing the amount of data in the image. Downsampling removes data and upsampling adds data. When you make an image smaller than its original size, you are downsampling it, when you make it larger you are upsampling.

You should always avoid upsampling your images. Adding data to an image will usually result in a very poor printed image.

Changing an Image Without Resampling

When you uncheck the Resample Image box, the amount of data in the image is unchanged even when you change the size of the image. This has the effect of changing the pixels per inch (PPI) of your image. For commercial printing, you want a rather high PPI value.

• For printing purposes you want 300 PPI or greater.

Which Image Formats Are Best For Printing?

When sending press ready design files to a printer you should send your images in the highest quality (not fastest) image format possible. Different image formats compress image data differently. PNG and TIFF images work the best for most print projects. JPG images work Ok at 100% quality, but every time the JPG is saved it is recompressed, so the quality can drop quickly if it is saved often at less than maximum quality.

How to Design Your Project for Binding

binding formats Binding is what holds books, magazines, catalogs or pamphlets together. There are many different types of binding, such as coil, wire-o, perfect binding and saddle stitching. When you're creating a bound piece like a catalog, it is very important to understand pagination. Pagination is how the pages will be ordered in your document so they'll be printed correctly.

Pagination can be very confusing because the way a document is printed is not exactly the way you look at it in your page layout program. InDesign allows you to switch to a printer spread view or a reader spread view. When you change your document to printer spread view the pages go crazy, and things appear out of order. This is the format that the printing press needs your document to be in so it prints the pages out and folds and binds them properly, a process know as imposition.