Design and more
PDF documents typically are WYSIWYG: what you see is what you get. The PDF document contains those elements that need to be printed and it contains thus "design" elements in a complete and accurate way. However, in many cases, additional information needs to be transmitted from the designer to the printer as well, and that additional information often is added to the PDF document.
Typical non-design content
It is a bit dangerous to call this additional content "non-design". It is strictly true, because such content will not be reproduced faithfully as is the rest of the design, but it can still influence the final appearance of the PDF document after print. Some examples:
- When designing non-rectangular jobs (such as labels and packaging), a cut line needs to be defined. This cut line indicates how the design is going to be cut to get the final printed piece.
- When designing something that that will be printed on a transparent material, it is often necessary to add an additional white ink layer underneath the rest of the design. This additional white layer is usually included in the PDF document, but it's usually included with a 'fake' (non-white) color appearance so it's visible in the PDF document.
- When creating complex jobs, it is often necessary to add all kinds of additional information to the job, such as job identity, printing and cutting marks, color patches, dimensions and so on. While this information is often critical to the job, it is of course not to be printed.
- Some jobs require special coatings or finishing processes; parts of a job might need to be varnished, may have silver or gold foils applied to them, or require embossing. These special processes are included in the PDF document, again with 'fake' colors to show where they will affect the design.
In workflows where such information is required, these special elements are typically indicated by using spot colors. Elements using a spot color with the name "White" refer to the additional white ink layer. Elements using the name "Varnish" indicate areas of the file to be varnished. Spot colors such as "Legend" or "Registration" or "Marks" may be used for elements that are not print content, but job identification or assisitive printing or cutting marks.
Problems with this approach
This approach with using spot colors raises a number of problems:
- The kind of jobs we are talking about here also typically use a list of spot colors for design elements (elements that do need to be printed in specific brand colors for example). Using spot colors for both design and non-design elements can lead to confusion.
- There is no standardisation on the spot color names used. The spot color used to indicate a die-cut line, may be called "Cut" or "Cutter" or "Die" or "Die-cut" or a variety of other names. On top of that, the design community today is global; a French designer will be likely to use a French name while a Finnish designer will use his own language. This makes it very hard to build any kind of automation for these files as key information can be encoded in a variety of different ways.