I have to say, depressingly, and let me say this right here and now: I do not
own Adobe shares; I'm not a marketing executive for Adobe, but the other day I
did actually save a PowerPoint presentation - something like 370
megabytes in total.
I'd used the "Save As PDF", available as standard in PowerPoint, and it reduced it
from 370 to all of 210 Mbytes. Wow! And it was a PDF and it viewed fine. I then put
it through PDF Writer. PDF Writer of course was a paid-for option - a pseudo-
printer driver - and it went from 370 MB to 10 MB, which I think
says something about the willingness to call upon compression technologies and
the expertise in preparing good PDFs.
Let's just backtrack a little bit and remind ourselves of the famous launch of PostScript in early 1985
John Warnock, Steve Jobs all that. And the example they used - we've got it here -
was John Warnock's original PostScript which, when imaged and rendered, produced
this "Supplementary Income Tax" form. But it was too slow for Steve Jobs to show
at the launch.
We've done some stuff on this. If you unroll the loops, flatten the code, then
you can get something that works in about 25 seconds. And that's what they did.
Now i know many of you will say: "Well, that's a good start but it's not enough.
What about this stuff you've gone on in the past about - lossy and lossless
compression? Yes. Obviously, in PDF, many of you will know, you can do lossless LZ
or LZW type compression on text. Fine - it's there, it's available. And, yes, in
images you are certainly going to need to be able to do compression of the JPEG
sort and to have it coped with by the PostScript - and indeed the PDF - 'image'
operator. So compression is of the order of the day, over and beyond abbreviating
things. if this is the glimmerings of PDF why did it take so long for PDF to
actually emerge? Well ...
>> Sean: How long ... what are we talking ... >> DFB: We're talking from 1985 when this
was done and the actual announcement of PDF and Acrobat its viewer software, was
late '92 early '93. So we're looking at seven years aren't we, there? More like
eight, probably, by the time you're finished.
Why did it take so long? And the answer is simple. You had to wait for people's desktop
workstations to become powerful enough to handle all this.
The common factor between the two [i.e. PostScript and PDF] is what's called the PostScript Graphics Model
which is magic. But remember, back in '85, the only computer in the room powerful
enough to render PostScript was the LaserWriter. The Macs were utterly
incapable of doing
it. A standard 9-inch Mac came with 128K. Just hopeless! And they
were so slow as well. Even slower than the laser-printer. So, there we are then, you realize
that if PostScript was going to develop away from being just something that
ended up being printed out on paper, into being something renderable on a big screen,
well for a start your screen's got to be capable of holding ... rendering .... US
Letter size, or A4 size, pages.
OK - relate that back to a tiny 9-inch Mac screen and the answer is: "Well, you'll
have to wait for that technology to develop". And you'll have to be prepared
to pay a fortune for your Apollo or Sun workstations for the 70 people in your
print room, or whatever it is, to use. But gradually, slowly but surely, it did come
along and of course by 1990 there was no question
PostScript had won the high-end [quality typesetting] war - completely and totally. So, what was their
recommended means, if you were a PostScript devotee, to get across to PDF
as a first approximation? And, for the sake of argument, we'll say, maybe, it was
Microsoft Word, or something like that here. And up until now, if you want
high-quality output - let's use ellipses for stuff that's in printable formats. So
we'll say PS here.
Yes, you could get Word to produce PostScript. You could send that
PostScript off [to an] Apple LaserWriter, or some other laser-writer that actually has got
PostScript inside it.
Adobe were making a fair bit of nice money, thank you very much,
supplying proper PostScript to go into laser-writers, right through to laser
setters at the very high [quality] end. The new feature now coming along, was to say well
if you put this PostScript into another piece of Adobe software, called Distiller,
this will turn it into this new and wonderful PDF.
Now you've got to give people a means of viewing it for free
- the famous Acrobat - but you have to pay if you want Distiller. So the next
question then was: "Yes, I'm a loyal PostScript person but that Distiller is costing a
fortune, Adobe! I'm gonna find somebody else who can do it for me". And, of course,
there were lots and lots of people who would do you a Distiller substitute.
It is not easy.
You have got to be able to take the most outrageously abominable PostScript and
not crash [when converting to PDF]. And I remember saying to an Adobe person at the time I said: "What's
wrong with a lot of these clones?" He said: "They get everything right but the thing they
can't handle is fonts". He said: "Well first of all y'know you've got to license
them? We've got permission from Linotype to use their stuff but if you've got to use
clone fonts and then you're in trouble. Do they quite match what was there on the
original? What the intention was?" And indeed fonts has always been a problem
in this. I once asked Bob Wulff the leader of the team that developed PDF, Distiller
and Acrobat Reader. I said: "Bob what were your six greatest challenges in
developing PDF?". And he said: "Dave that's easy,
fonts, fonts, fonts, fonts, fonts and fonts. In that order!
Those were my six biggest challenges" So, anyway the obvious question to ask,
since this is going to cost you a lot of money, is to say: "Well,look, Word needs to
get into this PDF form now, doesn't it? To go ... y'know be compliant?" Why not take a
flying leap around here
cut out the middleman, as it were. You don't need to go through PostScript any more.
Word, or any other app, could use a printer driver - a standard printer driver
type [of] thing. Except it's not really directly driving a printer, it's producing
a PDF file. Well they did - in very short order. They came out with PDF Writer and again
opportunity for third parties. PDF Writer, of course, was a paid-for option
to get this PDF. It was not free, like Reader. So a lot of people said: "We can do
a PDF writer that's good enough!" And some were better than others
inevitably. So to sum up, then, this is the nature of the PDF story.
It took a long time to get itself established but now it really is a
de facto standard and a very, very successful one too [and now an ISO standard]. The only big conundrum
still left and y'know for those of you who've seen my HTML video I
can only come back to this - that Tim Berners-Lee's comment to me about: "We've
got to find some way to marry exact representation and high-quality
typography with the flexibility to reflow stuff. And we're still, in a way,
poles apart
I mean HTML, despite CSS, cannot really aspire to the same standards of
typographic excellence as PDF can. And yet PDF is exact but rigid. Sometimes
people try and attempt to reflow PDF and its rarely successful. It's certainly not
easy. So I think John Warnock's comment - I just wish he would do something about
marrying these two views of the world - is yeah, one of the advantages of PDF and
PostScript is you can say: "Draw me on my screen a line that is exactly one inch
long". And it doesn't matter whether it's a 72 dpi screen or whether it's a piece
of bromide imaged at 2,000 dots per inch. That same command in either
PostScript or PDF 'draw me a line one inch long'.
Regardless of the resolution - get your ruler out - it will be 1 inch long. HTML [with no CSS] can't
do that!