Prepress Proofing

Why you should always have a prepress proof if colour and brand are important

Prepress proofing is a tool for customer and printer to verify that a job to be printed job is accurate. This is why it is also know as Contract proofing. Prepress proofing or off-press proofing is a cost-effective way of providing a visual copy without the expense of creating a press proof. If errors are found during the printing process on press, correcting them can prove very costly to one or both parties involved.

A proof allows the customer to check every small detail for errors before the printing process is started. A prepress proof is for colour reference and accuracy, pagination, to ensure all the relevant elements are within the job. It often also serves as a final proof for the customer to check finer detail, brand colour are correct, images are high enough resolution. For the printer it is more about, bleed, crops, colour fidelity, make up, separations and that the job has or will separate correctly.

No large printer with a long print run, such as a magazine or brochure will print a job without some sort of proof being signed off by a customer. Once you have signed the printer will run to this proof. These days everything is handled by computer, including the printing presses. The chances of something being printed different to what you have passed is probably almost impossible. Every sheet is scanned and check for tolerance as it passes through the printing press and it will inform the operator if there is any variance.

What is Prepress proofing?

Prepress proofing, sometimes called off press proofing, is a cost effective way to get a visual copy of a printing order without having to go through the labor and expense of a physical press proof. This method is not always best though, and when certain requirements like exact colour matching are needed then a physical press proof may be the best choice in spite of the extra cost and work involved.

What are the they type of proofs available

Soft proofs

Often referred to as a digital proof, a soft proof is a prepress proofing method that allows you to check a low resolution copy of the file. This file is often provided in a PDF format but can by JPEG or tiff file. Soft proofing simply allows you to check the final design elements to check that it has not corrupted or moved in any way.

Matchproof or chromlin proofing

Rarely used these days but still give the print an accurate guide to the colour expected. Cost if often the reason for not using these. Todays digital presses often can create a perfectly accepted final proof before litho printing and is far cheaper.

Hard copy digital proofing

As we have said may larger Lithographic printers have digital presses to ofter low run copies of magazine and brochures. Often you cannot distinguish between the two types of printing.

Wet proof

Wet proofs offers the highest level of quality for proofing any publication. They allow you to use the plates and stock that will be used on the final print run. Wet proofing is the only real way to proof items such as duotones or quadtones and is the best option for spot colour proofing. The individual proof is, however, hardly economically justifiable, however if the job is regular monthly magazine the settings are normally saved so this exercise need not be done again.

Press proof

Normally a Press proof is for the customer to watch the print come of the press and sign off there and then. However it is possible to have a Press proof is a test print of the data directly on a printing press.

Which proofing method is best?

All of these proofing methods are fine for proofing purposes depending of what your requirements are.

Soft proofing is perfectly fine for smaller run jobs and is the most cost effective method available if he colours in the graphics do not have to be perfectly matched with 100% precision. Sometime it is worth paying a little extra to ensure that what lands on your desk is correct first time.

Limitations

The limitations to all these proofing methods are the absence of Spot colour. Many of todays larger inkjet machines offer 11 colour RGB printing with can offer a great deal of accuracy of most of the Pantone range but not all.  It is best to assume that the pantone colour will be printed correctly and the Prepress proof is simply an indication or guide. A Press proof of course will be accurate.

What should you check when prepress proofing?

When you are prepress proofing you need to look at everything, ensure that it matches your last proofs all the elements are their, the pages are in the correct order, folios and headers are where they should be. Experience here is vital, something like this is not for a beginer. Check, check and check again, remember your signature is the green light for printing.