Date : Wed, 27 Jun 2001 16:36:42 -0700
From : Angus Duggan <angus.duggan@...>
Subject: Re: BBC Magazines
Chris Thornley writes:
>>Acrobat 5 is more than cosmetic; it includes a fundamental change to the
>>imaging model.
>And this means what exactly? Something written on the box? The reviews I
>have seen in various magazines seem not to rate its latest incarnation
>highly. Plus it has to be backward compatible.
Transparency. There is a whole new model for alpha blending, which
fundamentally changes the imaging model, and the constraints under which PDF
clients operate. *Please* trust me on this one, I write PDF/PostScript
interpreters and renderers for a living :-)
>>The PDF 1.4 format also supports much better editability;
>I hope so. I felt ripped off with some of its features when I parted with
>hard earned cash for it. Plus it has an annoying habit of playing around
>with which icon is associated with which file and suffers from memory
>leakage if left running.
You may have had different expectations. PDF was conceived as a transportable
visual markup archiving format. It was not conceived as a replacement for
application native file formats, nor as a tagged content format. It is being
retro-fitted with some of those abilities now, because of the way people have
used it in the past.
>>PDF 1.3 had the concepts of subject threads, but they weren't widely used.
>Subject threads hmm are they those annoying post it note things which you
>can get tagged to links, images or text with more information etc Very
No. Nothing to do with those; they are metadata that describe which parts of
the visual layout form story threads (think multi-page newspaper stories,
with continuations on different pages; subject threads associate which text
and pictures belong to which stories, and the order in which they are
layed out).
>>PDF 1.4 adds XML metadata tagging,
>What the use of meta tagging in a storage document. The only use of meta
>tags are for key words, expirery dates and refresh periods. Which are only
>of use if they on the web.
Rubbish! Metadata is a generic term for data describing the data in the file.
The XML metadata allows description of the data for automated search and
retrieval and re-purposing of content. This all goes back to the content vs.
visual layout debate; PDF 1.4 now has the ability to store both sorts of data
within one file (bloating the file size, of course).
>>and the ability to re-flow text in tagged PDF files.
>This might be useful but even more useful if I could export files. Also it
Export files as what? You're trying to translate from what has historically
been a visual markup format to a content markup format. This has never been
an easy job, it requires divining the designer's intent. Computers are not
(yet?) good at mind reading.
>annoying if you captured say a web page with black background and you want
>to switch it off for printing. There's no option. Also some times it
>captures same coloured text on the same coloured background and it murder to
>recolour it.
Like I say, I haven't tested the Capture part of Acrobat, so I don't know if
specific bugs are fixed. However, since Illustrator 9, InDesign 1.52,
PhotoShop 6 and other tools are all moving towards PDF 1.4 as a generic
import/export format, I suspect that it will be easier to fix problems in PDF
files in future.
This discussion is getting off topic, suffice to say the relevance to the
list is that PDF is still the most appropriate format for capturing old
magazine information. There are freely-available readers for a number of
platforms, the specification is freely available and implementable, and will
support the visual markup, content markup, and metadata required for scanning
old magazines. Bugs and limitations of current products are a consideration,
but should not be the whole consideration.
a.