flattening
Flattening is crushing a page built in several layers into one flat drawing, so that nothing shows through anything any more.
In more detail
A page as it is drawn is a pile: a photograph, a tint laid over part of it, a shadow under a logo, wording you can read the picture through. Each of those is a separate thing, and each knows how much of what is underneath it comes back through.
Flattening works out what every square millimetre of that pile actually looks like and redraws the whole page as solid shapes sitting side by side. The result looks the same. What it no longer has is the pile, so nothing can be moved or changed afterwards.
What it does on a real document
The engine leaves the pile as it was drawn and hands it to the printing works whole. Their own equipment does the flattening, at the fineness their press works to and on the day the job runs.
That is later and finer than a program on a desk deciding it weeks ahead, and it is exactly what the modern print standard was written to allow.
Where it comes from, and why
Pages were opaque marks in order for the first eight years of the PDF format. Anything showing through arrived in 2001, and printing works flattened it back out for years afterwards, because the equipment on the floor was older than the idea. Presses caught up, and the rules were rewritten in 2010 to let the pile through.
See it on a finished document
Transparency and blend modes A sheet prepared for the printing works The rules behind this word, and the texts they are read from
Glossary
- print standard
- The published rule a file has to satisfy for a printing works to run it as it stands: the colours stated in the inks a press lays down, the lettering inside the file, and the page saying where the blade cuts and how far the colour runs past it. PDF/X is the one the trade asks for by name.