Bell Labs got its first actual laser printer in 1982, which I think was from a
company called Imagen. Now in those days yet you could get them but the big
problem - the big big problem - was fonts. It wasn't by any means impossible to get
laser-printer technology - at lower resolution than the Omnitech was doing
[and] more reliable, in Nottingham and we asked for a price, I think, for an Imagen
early laser printer and we were told it would be $18,000 in the UK, which would
have translated to about 15,000 pounds. It was ridiculously expensive. If you're
getting to lower resolutions, like 300 dots per inch, what then happens is that
your eyes are sensitive enough to notice roughnesses on the edge of the character.
In other words the pixel density of 300 dpi is such that if something goes wrong,
in terms of the pattern of pixels, and you get a fault at the edge of the
character your eyes notice it. At 972 dpi they probably wouldn't notice at all.
So, the burning question was: "How can we do this
rounding problem, if you like. We've got these beautiful outlines; we need to
translate them into dot patterns. How do you work out which pixels to turn on,
which to turn off. And if you've got half a pixel, by the time you've done your
calculations, do you turn it on or do you turn it off? And, of course, you can
imagine what happens. It looks bad if you didn't turn that pixel on; it looks even
worse if you did turn it on! You just couldn't win. It was a huge problem and
within the industry there was the most ferocious debate within Xerox,
Canon, wherever. And even - many of you know - the computer scientist who got
involved, around about this time, with typesetting: Don Knuth. And the
consensus was that down at low resolution you just had to have
hand-tuned bitmap fonts, with all the pixels put in place correctly. There was
no shortcut. There was no way that you could, if you like,
on-the-fly, scale down from outlines to dots on a drum and get it right automatically.
Hand tuning was the way forward. Well if that was the case it was
a real mess. Because it meant that your laser printer had to be backed up with
an expensive hard disk, or cartridge, system. And some commenters already, on
the Jailbreak [202-system video] who have used these, say what a nightmare it was. You had a very
restricted range of fonts. They never seemed to work correctly and that whole
disk, instead of a holding 50 or 60 different typefaces, was devoted to
holding Times Roman hand-tuned in about 40 usable point sizes. Stuff like that.
The thing that kept us going though - the rumours on the horizon if you like - were
that two people, working for Xerox PARC, called Warnock and Geschke, were about to
leave Xerox PARC and form a new company called Adobe. Now, the moment you say Xerox
PARC you start thinking: "We need a complete new video just on that alone".
PARC -- Palo Alto Research Center If Bell Labs was the one place that
everybody wanted to work at in the 1970s then Xerox PARC was certainly the other.
And there was a similar background in some ways. Bell Labs had lots and
lots of money, because of AT&T, but of course they were under consistent
scrutiny for "monopolistic practices" and don't you ever dare turn yourselves
into a computer company - it wouldn't be allowed. Xerox probably didn't have quite
as much money as Bell Labs but nevertheless, even today, Xerox I
think, turns over about twenty billion dollars a year. So, they could afford a
vanity project and they did. The Xerox Palo Alto Research Center was run off
the Xerox publicity budget! That's how much money
Xerox were making. And they still do make, just out of being a photocopier company. But at
Xerox PARC they invented - either invented or had a very strong development role - in
all sorts of things that are now commonplace. The computer mouse; the laser
printer; bitmapped terminals - which we take for granted nowadays - but if you
skip back to my earlier video on "From Mainframes to Unix", just take a look at
what the old character terminals used to be like. Sort of cells of dots - about
9 x 9, with the characters in. You certainly couldn't get down to the bit
level on your screen - but with bitmapped terminals you could. They had under
development at Xerox PARC things with names like Alto and Dorado, bitmap
terminals, Wonderful! And they had Bob Metcalfe there. They were crucially
involved in the development of Ethernet. They had it all. They had all the
necessary components to pioneer the next stage of computing. If you like, the
workstation revolution. But in a book, I think, called "Fumbling the Future" the
author of that book makes the case that they fumbled it - they let it all fall -
they didn't market it and they could have done. Well, to be fair to Xerox, at the
time, you could argue they made the right decision. Turning yourself into a
computer company is hard to do, if you're not a computer company already.
And wonderful though their technology was, it was reckoned at the time that the cost
of the components alone, in mid-1970s money, to make an Alto terminal - the
components alone would have cost $10,000. If they were mad enough
to go into marketing the thing they would have had to charge at least
$25,000, in 1975 money, probably about $250,000 in
today's money. So, you could say, in a sense, they had to wait for the cost of
the technology to come down. And they had to accept that all these toys were very,
very expensive indeed. Now the only problem was, with sitting on, and
developing, all this wonderful technology was that the hot-shot computer scientists
you've got working for you, got very frustrated that their wonderful
inventions, and developments, were not being marketed. And so, gradually, as the
70s wore on into the 80s, people began to leave and to form their own
startups. Chuck Geschke, John Warnock, both considerable computer scientists in
their own right, were working on Xerox's Interpress language and just got so
frustrated with Xerox's inability - a lack of will to market this properly - that
they upped sticks, left, and formed Adobe. Which you've all heard of, in late 1982.
I think they initially decided that they were going to go for the high-end
typesetting market. Soon after they left and founded Adobe, John Warnock got to
work on a language that's achieved great fame ever since, called PostScript.
I think it very carefully avoided the precise way that Interpress had done
things, and it reverted back to lots of John's earlier work, because he was a
computer graphics specialist, who came out of the University of Utah, and also
worked for the graphics company called Evans & Sutherland. And in his
PhD he solved the infamous hidden surface problem which had defied
efficient solution for quite some time. I think I've already told you, in the video
I did about David Huffman and Huffman trees - his PhD thesis was 12 pages.
I think John told me that his PhD thesis, about solving the hidden surface problem,
was a little bit bigger - all of 32 pages. So here was this computer scientist - a
computer graphics expert - joined up with another considerable computer scientist,
Chuck Geschke - it was the ideal combination to found this new company.
John came up with this language called PostScript, which was going to be a tour
de force of two-dimensional graphics and it was. And, more to the point, he was
going to get to grips with solving this problem of how to make fonts look good
at low resolutions. You want to hold the outline of the font as arcs, splines,
lines, whatever, for as long as possible. But, in the
end, it has got to get down to being pixels. It's got to be dots on a laser
printer drum. And, in fact, there's some other stuff of course. John Chapman's
videos on "Computerphile are so relevant to this. You really ought to watch them. So
here's some more detail which relates to that. Oh! by the way, thanks to Fontographer
those of you want to know how I did the so-called PrintOut font, in the
"Jailbreak" video, I think the papers that we Web-link to
make this clear but anyway, I used Fontographer and within the Fontographer
manual, there is a very useful pair of pages which makes very clear this
difficulty with getting characters to look good on a coarse resolution.
Consider a letter H. Here's the outline superimposed on top of a grid of pixels.
Now, how do you decide which pixels of these vertical stems are to be colored in?
If you follow the argument that a pixel should be made black only if it's
totally within the outline, then if your outline isn't quite as helpfully aligned
with the pixels as it might be, this is what you end up with. On the left hand
side the only ones that are totally within the outline is a single column,
whereas on this [right] side there's two columns. If you back off, take away the grid of
pixels at the back, and look at what the character looks like - it's awful. Y'know,
you've got uneven stem widths. And do notice in these, of course, the crossbar
is gone [missing] on the H. Isn't that wonderful?! Of course it would go - it's so thin, in that
design, it's been rounded down and it's vanished completely. Here's
another thing. Even if you could solve that, these 'flicky bits', as we know, are
the tops and bottoms of characters. I think probably everybody knows they
are called 'serifs'. Well you'll need your serifs to look good as well. And, if you're not
careful, you can end up with the stems getting better and more equal
but the serifs having no symmetry whatsoever, even though they're supposed
to be the same shape. The precise way they align with the
grid underneath is such that they don't look symmetrical anymore, whereas they
were in the first instance. And then you can say: "Oh! could we solve all of this by
saying: well tell you what, we'll turn the pixel on if any part of it touches the
outline, however glancing, if you like, the impact is between the pixels and the
outline. If it's at all remotely touching turn it on". And that's the kind of mess
you end up with if you do that. So, what you needed was a system of what came to
be known as 'hints'. On the diagrams here, for the letter M, hints show all the
places in which the Adobe Type 1 font system actually said mattered.
Hints about the serifs, these are important, take care.
Hints about horizontal lines like on the H, don't round it down and don't have
it disappear altogether. Within the font mechanism it was, basically, when you are
scaling down the outline and as John Chapman's videos will also show you, in the
end, although you can delay doing a straight line approximation to curves, in
the end that's what you do. You end up with triangles and polygons, OK? And then
those triangles and polygons, you work out where they intersect with the
underlying pixels, and so on so. Late on in the process - and this is the advantage
of this more modern approach compared to the 202, rather faster processors, you can
leave the - as it were - translation into straight line approximations and pixels
until the latest possible moment, thereby giving yourself flexibility. Now this
shows you this is Linotype 202 resolution up at the top. That is the
base, I think, of a stem of a letter H, or I, or something like that at something
more like 970 dots per inch, and you see there's no problem. If you back off from that your
eyes are probably not sensitive enough to notice the odd pixel that's gone
astray but down at 300 dpi they certainly will. And, of course, the problem
manifests itself hugely at 300 dpi if you have small point sizes, like
6-point or 8-point. You end up, if you're not careful, with everything
looking just like a full stop because there's been so many errors, So, this is
why you need these hints. You need stem hints; you need serif hints; you need
hints to stop horizontal things vanishing altogether, due to rounding
down. John Warnock was the recipient of a very prestigious medal called the Lovelace
Medal [from the BCS] and my friend, Conrad Taylor, has done a report on that talk, which he is
happy for us to use. And in Conrad's report you will see that John Warnock
actually admitted - 20 years after the event - that there was another dirty trick
that they did as well as, if you like, as part of the hint that they didn't let on
about. If you look back at this diagram here and how it translates to turned on
pixels here, although we will enrage the type designers there is a way that you
can help yourself here. Type designers like calling the gap to the left of a
character the 'left side-bearing' and the gap at the right of the character the
'right side-bearing'. Now, if you look carefully, the left side-bearing here is
absolutely wider than the right side there. This is part of the design. You
position your character within the cell, so it looks right in all combinations
with all other characters and even in a fixed-width font - like PrintOut of the
previous [Jailbreak] video - you found that left or right side-bearings are still not equal. Yeah!
But what John and his Merry Men did in their Type 1 renderer was to say:
" ... actually although the designer will kill us they probably won't notice if, at
the very last minute we just shove the letter H ever so slightly further left".
OK? So that, instead of ending up with a one-pixel line and a two-pixel line,
you might end up with both of them being one and a half, because you've made
the alignment of the character against the background grid be just much more
sympathetic. And if it's one and a half it doesn't matter whether you round both
sides to 1, or round them up to 2. They are at least going to be equal. OK ? That's
going to help a lot. So, he actually admitted in 2004 that it was not beyond
them to ever-so subtly shift the character, within its unit cell, to get a
better alignment and a better result. So that is, then, pretty well a summary of
what had to be done, what had to be got right with hinting before, if you like,
quality fonts stood any hope of working properly with laser printers. John
Warnock put the PostScript language, effectively, into the public domain and
said: Go on - implement it! I want it to be a standard". You know: "Implementation is the
sincerest form of flattery" - as one of the first implementers said. But the story
was this: you can use all the graphics operators in PostScript, you could do a
pretty acceptable font that way. But it was what Adobe called, at the time, a Type
3 font. It did not have these hints to enable you to survive and make it look
good down at very small point sizes, on low resolution devices. If you wanted
that then, back in ... from about 1985 to 1989, you had to sign a contract with
Adobe to license their hinting technology. And this was secret; this was
one of the ways that Adobe, as a young company, wanted to make money. They were
selling PostScript implementations, of course, to other printer manufacturers
but there was a nice font revenue stream from licensing people to put Type 1
hints onto Adobe Type 1 fonts, So, there we are then. There's another story to
come here, but we'll get onto that later, about how Adobe survived with that model
for about four or five years. But eventually Gates and Jobs were not going to
pay endless royalties for Type 1 to John Warnock, dearly though they loved him.
And we could do a talk at some stage about the emergence of TrueType out of
that. But for the moment here's the story then. You needed a laser printer equipped
with PostScript but with PostScript plus the ability to cope with Type 1 fonts
and - do be clear - this hinting information, things like: "... these stems should be of the
same width; that cross-bar on the H - don't round it down and don't lose it! " This is
used at the very last moment when you're converting things into pixels on the
imaging drum. And it's ultra, ultra important that you get it right. But,
effectively, John and his Merry Men with PostScript and the hinting, had
solved a problem which many people in the industry said was insoluble. Y'know:
" ... there isn't a way to take outlines and round them down, to all point sizes, and
make it look good". Well, you might say that some of the tricks that John did
were compromises and were a little bit short of perfection but frankly, even to
type professionals, I don't know, if you did an A and B [comparison]. You know, hand-tuned
bitmap vs. what the Adobe Type 1 mechanism did with that H. OK, with a
good microscope you notice the difference but, for everyday use, no
problem at all. The problem was solved essentially.