Introduction to the Printing Process
We will have a quick look at some of the print processes involved in getting digital artwork into print and cover some rules you should follow to avoid disappointment.
For this article I am going to focus on a business card as an example, since these are nice little graphic designs, not too complex but still can involve all the processes. You can learn how to create a business card with InDesign in my graphic design tutorial.
There are several different types of printing process, and depending on which one you are planning on using, you may need to structure your designs towards that particular process.
Letter Press Printing
Although the process of the original letterpress hasn't changed, modern advances allow automatic re-inking and continuous print from spools of paper.
It can be a clever idea to add to your design, but it does cost and can detract from usability if the materials or shape does not fit the standard form.
Printing and Pre-Press Basics
So far we have covered a lot of software and application tool and processes, but equally important are the printing processes. These occur when you send your designs off to print. They are important as you do want to get the results you expect when they come back from the printer.
There are several different colour modes available when designing. These are covered in greater depth in the colour theory tutorial but just to recap:
RGB - Red, Green and Blue colours are for display as pixels in the screen are formed of red green and blue LED's. Adding Red, Green and Blue together in light form creates white.
CMYK - Cyan, Magenta, Yellow and Key (black) - These are for print. Adding combinations of these colours creates other darker colours. All added together make black in print. Key is black ink and used for blacks as it is a darker shade and does not waste ink from the other colours.
When designing for print, ensure you use CMYK colour modes as the conversion can be very very different from what you originally intended.
This is the bane of printers. When designing for web or display, you should use 72dpi but when designing for print you should always use a minimum of 300dpi. Lower resolutions will create very poor images when sent to print. Some printers will even refuse anything less than 150dpi as the quality is just too low.
Plain Black vs Rich Black
Not all colours are created equal. There are different shades of black and believe it or not you can create a deeper, darker, blacker black using colours than you can by printing black itself.
This is all down to the make-up of the colour and the percentage of each ink used. Plain black uses CMYK values of 0, 0, 0, 100 whereas a rich black would use 75, 68, 67, 90. This rich black uses portions of all colours mixed together. This is the default mode in Adobe.
It is important to know the differences between these. It is generally not advisable to use completely saturated CMYK levels as it will saturate the paper with ink. It is also not advisable to use a rich black when printing text. This is because when printing plain black, there is one layer of colour printed. When printing rich black there are four layers printed, one on top the other. Any variation, of which there will be some albeit very tiny, will make the text appear slightly blurry.
Typography is an important design element to consider when sending designs to print. You should always avoid applying characteristics like bold or italic to fonts. These are generally system generated and will change between systems. Always use fonts from the typeface which are specifically designed for the print process - example would be using "Helvetica Bold" instead of using Helvetica and applying a bold characteristic to it.
Marks and Bleed
Marks and bleeds are effectively in the margins. The bleed area is excess image that is not within the printable area. This excess image is printed on the printer on the paper stock but is then cut down to size. Bleed is required as the paper may move around slightly during the print so bleed ensures that there is no area left unprinted. Bleed also allows edge to edge printing. You should ask your printer how much bleed it required. Generally 3-5mm is required.
Trim marks are small marks added to the margin so that the printer knows where to cut and trim the document. You can also add in colour bars and registration marks. These help the printer align up each colour plate correctly. Colour bars are used to ensure that the ink density is correct. Printers usually set these up themselves, but check with your printer first.