I’m a big fan of preflight.
Now, we saw last time that Adobe supplies a very good collection of preflight profiles, but none of them do everything that I want in just the way I want. The most excellent thing is that you aren’t limited to Adobe’s preflight profiles; you can make your own and have them exactly fit your needs.
Let’s see how to do this. In particular, let’s put together a preflight profile for an eBook-that is, a PDF file that will be primarily viewed on a computer screen.
By the way, do go back and read the previous article on using Acrobat’s preflight; this article will assume you know what a preflight profile is and how to run a preflight session on a PDF file.
But First: What Does Preflighting Do, Exactly?
It’ll be helpful, before we assemble our new preflight profile, to be clear on what, exactly, Acrobat does during the preflight process.
The Acrobat code that carries out the preflight analysis-let’s call it the preflight engine, for short-scans through a PDF file and accumulates a large list of characteristics of the file and its contents, including fonts (their names, types, and embedded statuses), images (size, resolution, color space), and line art (colors, color spaces, line widths, use of transparency). Having compiled the list of characteristics, the preflight engine generates a report, listing each bit of information it collected (call it an incident) and tagging each incident as to how it should be reported, depending on the degree to which it represents a problem with the file.
There are four possible reporting statuses that an incident may have; in order of increasing potential dire-ness, they are:
- Inactive: Not a problem and not of interest. This represents a characteristic that is guaranteed to have no impact on the success of the PDF file. An example would be transparency in a file intended to be viewed on-screen.
- Info: A characteristic that’s interesting, but not really a problem. For example, I’m always interested to see if there are any Type 3 fonts in my documents; these days Type 3 fonts are rare as hens’ dental work, and I’m professionally curious as to why they appear at all. However, Acrobat handles Type 3 fonts perfectly well, so they don’t in any sense constitute a problem.
- Warning: This is something that probably isn’t a problem, but should be checked out anyway. For example, a very low-resolution image is a problem if it’s a photograph; it’ll be overly chunky and ugly. On the other hand, if the image is a screen shot of some tiny UI element blown up for easy visibility, it’s purposely low resolution and is OK (Figure 1).
Figure 1 A low-resolution image may or may not be a problem that needs fixing, depending on the image’s content. The photograph looks annoyingly pixelated, but the icon is legible and usable.
- Error: This is unambiguously a problem; the document should not be used without addressing the situation. For example, a file intended for professional printing shouldn’t have any RGB colors in it; these will produce indeterminate results when separated and sent to a printing press.
Of course, whether a particular characteristic is a problem or not depends on what you’re going to do with that PDF file. RGB colors are a problem with a file intended for professional printing, but are perfectly OK for files that will be viewed on-screen or printed on home inkjet printers.
As we’ll see when we create our profile, each check that the preflight engine can perform is represented by a drop-down menu that lets us specify how that check should be reported (Figure 2). Creating a preflight profile consists mostly of trudging through all of the characteristics that the preflight engine can look for and telling Acrobat in which category each belongs. Tedious, but pretty easy.
Figure 2 Each check that the preflight engine can make is associated with a drop-down menu that lets you specify how that check should be reported, if at all.
That said, let’s make an eBook preflight profile.