MacBook back-up necessity
in [UK Mac]
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From: Woody on 2 Jul 2010 05:32 On 02/07/2010 10:18, Jochem Huhmann wrote: > usenet(a)alienrat.co.uk (Woody) writes: > >> A PDF can not be set up in such a way to let you know what a piece of >> information means. >> >> Really at a basic level it is quite useless for structure. Even a table >> is a collection of words with lines drawn in it - there isn't the >> constructs inside a pdf to let the information within a table relate to >> itself. >> >> Once information has gone into a PDF, it is just words, any structure it >> has is completely lost. >> >> It is a purely display only format. > > There is tagged PDF though, which tries to address exactly this problem. I would say that it is really starting from the wrong end. Wouldn't it be better to start with something else that had structure, and put the display layout into it? You can embed full XML structures inside a PDF (or anything really, videos, viruses, whatever), but is that not just trying to re-engineer something to cope with something it was never designed (and contains no structure) to do? Effectively you would just have the information twice -- Woody
From: Jochem Huhmann on 2 Jul 2010 05:45 Woody <usenet(a)alienrat.co.uk> writes: >> There is tagged PDF though, which tries to address exactly this problem. > > I would say that it is really starting from the wrong end. Wouldn't it > be better to start with something else that had structure, and put the > display layout into it? If you start out with just content and structure (like an XML document in DocBook or such) and generate a tagged PDF from it this point is somewhat moot, I think. > You can embed full XML structures inside a PDF (or anything really, > videos, viruses, whatever), but is that not just trying to re-engineer > something to cope with something it was never designed (and contains no > structure) to do? > Effectively you would just have the information twice If you first generate a PDF and *then* try to put the structure into it afterwards, yes. But if you're starting out with a different format anyway and PDF is just one target format, creating tagged PDF is not a bad idea at all. At least this allows screenreaders to work, text to be re-flown, etc. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery
From: D.M. Procida on 2 Jul 2010 06:00 Jochem Huhmann <joh(a)gmx.net> wrote: > > Once information has gone into a PDF, it is just words, any structure it > > has is completely lost. > > > > It is a purely display only format. > > There is tagged PDF though, which tries to address exactly this problem. PDF is basically built upon PostScript, a language intended to be interpreted by laser printers. All it does it tell the device: make such-and-such a mark here. It seems like the worst possible starting-point for trying to preserve semantic content, never mind achieve accessibility. Daniele
From: Jochem Huhmann on 2 Jul 2010 06:21 real-not-anti-spam-address(a)apple-juice.co.uk (D.M. Procida) writes: > Jochem Huhmann <joh(a)gmx.net> wrote: > >> > Once information has gone into a PDF, it is just words, any structure it >> > has is completely lost. >> > >> > It is a purely display only format. >> >> There is tagged PDF though, which tries to address exactly this problem. > > PDF is basically built upon PostScript, a language intended to be > interpreted by laser printers. All it does it tell the device: make > such-and-such a mark here. > > It seems like the worst possible starting-point for trying to preserve > semantic content, never mind achieve accessibility. I'm certainly not advocating to use PDF as starting point for anything. PDF is almost always created from something else (which may very well have some structure in it) and if you have to create PDF anyway, a structured PDF is better than an unstructured PDF. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery
From: Pd on 2 Jul 2010 06:22
Woody <usenet(a)alienrat.co.uk> wrote: > > There's no way a book containing large art prints can be rendered in a > > form that can be enjoyed on an e-book reader in the same way. > > ok, I will give you that. Didn't occur to me as I wouldn't be looking at > large art prints. However pictures in general I wouldn't have a problem > with on an iPad style screen (the proper ereaders are very bad at > pictures), just not crammed into a proper book form. Plus computer screens can be better at displaying full colour pictures - especially once we get into 300+ pixels per inch. One pixel on a screen gives you the full range of colours in the available gamut (is that a redundancy?), whereas a CMYK image printed at 300dpi takes a lot more dots to give the illusion of the same colour. A book of large art prints would need to be printed at a minimum of 600dpi to give the same detail as an iPad screen, depending on the process used. -- Pd |