Production Scenario: SWOP v2
-----It’s time to send our (InDesign or QuarkXPress) file to the printer. We have edited our pictures in Photoshop and Placed them into the document. --------Since we know that printers prefer tidy, hermetically sealed CMYK PDF files, we dutifully “Export” our file from the File menu and choose “Press Quality” from the PDF Preset menu.
-----We choose this because we will be printing this file on a printing press, and this choice automatically selects all the “correct” settings for the printing press. Since it’s not really clear what all the “Standard” menu choices mean, we’ll choose “None.” --------
-----We’ll leave the other settings in their default settings. A click of the OK button and bingo! The file is ready to go. Adobe has made this so simple! This preparation model is repeated many thousands of times every day. ---------------Most people have no reason (or knowledge) to change any settings. Certainly the default Press Quality settings will produce the best results! ----------In Adobe we trust!
-----You might want to reconsider that assumption.
-----Before any pre-press choices are made, you must know (a) the printing process, and (b) the type of paper that the project will be printed on. This is not rocket science, it is very basic, available information. If you don’t know the answers to these questions, certainly the printer does. Do not blindly choose “Press Quality” from the menu and accept the defaults. --------Doing so will deliver a one-size-fits-all result. The choices you make when converting your file to PDF are of major importance and will determine the appearance of your project.
Not All Printing Presses Print The Same
-----There are many different types of printing processes, each requiring a unique machine, and each transferring ink onto paper in a unique manor. Therefore, for best results, each of these presses requires unique file preparation.
-----Printing inks used by a high-speed web press are the consistency of light syrup while sheet fed press inks are more the consistency of peanut butter. Each ink formulation requires a different screen frequency and each screen frequency requires different dot gain compensation.
-----Here's an illustration…
-----While an automobile-size engine works fine for an automobile, it is at the same time inadequate to power a trailer truck and yet tremendously overpowered
for a go-cart. True, all these are vehicles that are powered by engines, but no one engine is appropriate for all vehicles.
While all machines require oils to lubricate internal moving parts, smaller machines require thinner viscosity oils. Motor oil doesn’t work well in a sewing machine.
Principle learned: One size doesn’t fit all!
LPI and Dot Gain. -One little-publicized factor in the composition of separation tables is the “screen frequency” to be used. Screen frequency is the number of printing dots in the space of an inch. The more dots in the inch, the more dot gain on the press.
-----This means that two copies of the same picture, printed on the same sheet of paper, going through the same press can look different simply because one is printed at 120lpi and the other at 200lpi. If both pictures use the same separation table/profile, the 120lpi picture will print lighter than the 200lpi picture. Welcome to litho. This won’t hurt, did it!
-----What Does This All Mean? Simply put... many factors determine the makeup of a suitable separation. One thing is for certain. Never NEVER simply select “CMYK” from the Mode menu in Photoshop, or the Profile options in Acrobat, without first knowing what will happen to your image.
One-size-fits-all actually fits nobody!
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