What does the term "Pre-press" mean?

Pre-press is an term used in the printing industry and refers to the steps taken after the printer receives the digital files until just before the actual printing. These steps are taken to prepare the media and make it into a format that is ready for printing. 

The process generally involves 3 steps.

Step 1. Pre-flighting

The first step in the process is called pre-flighting. When a client submits their digital files to a pre-press company, this file must be checked to see that it will be compatible with their systems.

For example, a client may submit a pdf file which includes pictures and text.  A picture may not be of proper resolution, or a font may be missing.  Usually only experienced pre-press personnel are used for this check as they have experience in seeing the final printed result.

The client no doubt has experience in making publications, but printing processes can be unique.  One pre-press company may use one type of software and printing press, while another uses completely different equipment and software.

Here are a few things that are checked in this stage of pre-press:

• All pictures are converted to CMKY
• Pictures bleed properly to edge when on press
• All fonts are included in the file
• That pictures are proper resolution
• Crop marks, bleeds and margin marks are all present and arranged

Some companies make "pre-flight software" that is designed to look for all of these mistakes.  While they do catch many of them, nothing replaces experience.  The pre-press personnel have seen what works and what doesn't on their particular equipment.

The whole objective of this step in the pre-press workflow is to catch mistakes.  It is quality control.  It will find problems before they become a costly correction later when printed. 

Step 2. Proofing

Once all corrections have been made in the pre-flight process, the pre-press department will make a proof.  This is to make a visual representation of what will be printed on the press. It is like a draft.  

This is usually the first time that a client can see what the final product will look like. Sometimes it is a hard copy, but often it is a pdf file as in the case of business cards. 

If a printed copy is provided, it allows the client to see how the product will be folded, page order and overall look.

The pre-press department will then likely ask the client to sign off on the proof.  This means that any changes from this point on take place at the cost of the publisher, not the printer. If there are any deviations from the proof, the printer bears the cost.

This is an important agreement because any changes from this point on are very costly.  Press time and materials are expensive. There must be no misunderstandings about what is acceptable.

Step 3. Printing plates (for offset pre-press)

This third step in the process only involves offset printing presses because digital printing does not require plates.  

The pre-press department now makes printing plates and burns an image on to metal (and sometimes paper) plates.  If the job has color, four plates will be made: black, cyan, magenta and yellow.  This will be done for each page that has color. 

Now that the image is burned, the plate will be crimped on the edges so that it can be mounted on the printing press.

The pre-press department will then give the signed proof to the printer so that it can run according to the standard approved by the client.  If the press operator sees anything different than what is on the proof, an approval is required from the publisher.

From this point onward, pre-press is no longer part of the process.  The three preceding steps have been critical in making sure no time and materials are wasted.  The offset press operator now has the responsibility to make sure that the entire run is done according to the standard approved by the publisher and pre-press.