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+\providecommand{\ie}{\emph{i.e.}}
+\providecommand{\ctan}{\textsc{Ctan}}
+\providecommand{\cd}{\textsc{CD-rom}}
+\providecommand{\unix}{\textsc{Unix}}
+\providecommand{\dos}{\textsc{Dos}}
+\providecommand{\ie}{\emph{i.e.{}}}
+\let\textss\textsf
+\title{Malcolm's Gleanings}
+\author[Malcolm Clark]{Malcolm Clark\\
+Computing Services, University of Warwick\\
+Coventry, CV4 7AL\\\texttt{m.clark@warwick.ac.uk}}
+
+\begin{Article}
+\section{True colours?}
+The boost given to the use of colour in \LaTeXe\ is not an unmixed
+blessing. There are pitfalls and problems lurking round these new
+corners. There is always a huge discrepancy between the colours we
+can produce on a monitor screen and the hard copy version that a
+printer will produce. It can be very frustrating to spend time and
+effort getting the colour balances `just right', and then finding that
+the hard copy looks nothing like the original. Especially when you
+have to pay for the hard copy. Why are there discrepancies? The
+mismatch is in the very nature of the processes involved -- it is not
+because something has gone wrong.
+
+Let's start at the beginning, and assume that we are concerned with
+the transition from colour on the screen to colour on the page.
+Perhaps the first thing we should realise is that no two people see
+colour in quite the same way. Intra-species perception is well-known
+to be different, but even between individuals (ignoring those with
+some physiological perceptual malfunction, like colour blindness),
+response to different colours is different -- \ie\ what different
+people call `blue' differs -- well, most people agree about blue, but
+how many agree about `mauve' or `puce'? Any perceived colour may be
+understood as the sum of three primary colours. This gives us a first
+clue, since it means that we can represent a colour as the sum of
+three stimuli (a tristimulus), and we can think in terms of
+characterising any colour by locating a unique point defined by three
+(orthogonal) axes. In fact no monitors can represent the full range
+(or \emph{gamut}) of colours. Their actual performance falls short.
+Even before we start, we cannot hope to represent all possibilities.
+
+The colours we view on a monitor are emitted colours -- they are
+generated by the three electron guns of the device (there are other
+technologies, but the principle remains much the same). The advantage
+here is that each model of monitor can be calibrated, and in fact the
+range of possible colours can be determined. From time to time the
+colours may drift, and it is possible that adjacent `identical'
+machines may appear to have different colour outputs. If you always
+work on the same machine, you can guard against this. Recalibrating
+every machine is rather time consuming. Another advantage of using the
+same machine every time is that the background and lighting is
+unlikely to change to much.
+
+By virtue of our evolution, our eyes are well adapted to slow changes
+in light level, and also to slow, but moderate changes in the major
+illuminant (as daylight varies through the day, for example). Changing
+the incident lighting does not change the emitted light on the
+monitor, but since the frame of the monitor and everything else in the
+room is changed by changing the illumination, you can end up thinking
+that it looks different. The illumination in many rooms is a bit
+arbitrary: it may be fluorescent tubes, which have a rather limited
+spectrum, or it may be normal incandescent lights, which have a
+different spectrum, and occasionally it is north light (also known as
+\emph{daylight}) illumination.
+
+This last is an interesting diversion. This is the lighting condition
+under which most, if not all, standardised colour determinations are
+performed. Anyone who is working seriously with colour will use north
+light (most artist's studios, for example, will be oriented to be lit
+naturally in this way). In fact, this is one of the reasons why the
+hard copy will appear incorrect: the lighting conditions are likely to
+have changed. And anyway, the hard copy will look different under
+different illumination. The hard copy is made visible by reflected
+light. What is reflected is dependent on the light source. The
+distortions of sodium street lights are well known, but the same sort
+of effect is true of fluorescent or incandescent lights. The north
+light works reasonably well as a standard because of our environmental
+background, and because it is based on the light source which was
+available as our eyes evolved.
+
+There is at least one more factor to be considered: the printer. Just
+as a monitor can only produce a proportion of the possibilities, so
+too the printer is restricted in its range of possible colours. In
+fact it is worse: while the monitor can use the linear additivity of
+the primaries, the printer's primaries are anything but linear, and
+the mixing is subtractive. Adding the primaries on a monitor gives
+white: on the printer it will give a theoretical black (more of a
+muddy purplish darkness). It is therefore rather difficult to
+transform from the co-ordinates representing the colour on screen to
+some faithful (whatever that means) rendering on the page. There are
+lots of dodges which can be adopted. The most comprehensive is to
+employ some sort of lookup table. This depends on the measurement of
+many samples -- it is a lot of rather tedious work, spread over lots
+of subjects (remember the underlying psycho physical variation).
+
+Briefly then:
+\begin{enumerate}
+\item the colours you see on the monitor are a subset of possible
+ colours;
+\item the illumination of the room can be important
+\item the printer does not have the capability of rendering all the
+ colours visible on the monitor;
+\item you will probably view the hard copy under a variety of lighting
+ conditions.
+\end{enumerate}
+
+Is there any hope? Some printers are better than others. The machine
+we use here at Warwick, a Tektronix Phaser, is essentially a wax
+crayon machine; it is reasonably good, for the price. The best hard
+copy devices are dye sublimation printers and they are very expensive.
+If you stick to primary colours, and colour gradation is not a key
+issue, the Phaser is excellent. With a lot of time and effort you
+might achieve finer quality work with it. If you are looking for a
+photographic quality reproduction you would have to use other
+technologies -- and even then, you can fail. In many cases though,
+hard copy is irrelevant. The display medium is genuinely the monitor
+screen. If we think in this way, we realise that many other
+possibilities are introduced, like running video clips, or even pieces
+of software, within a document or presentation (yes, \LaTeXe\ does not
+yet support such extensions explicitly, but a suitable
+\texttt{\char'134special} could). We usually have the feeling that
+paper is the objective, but it does not have to be. Sometimes it is
+more convenient, but at other times it is restrictive.
+
+Any of the good ideas for this came from presentations by Chris Lilley
+of the Computer Graphics Unit at Manchester Computer Centre; the
+mistakes are mine.
+
+\section{Trivial pursuit}
+For many years I have been toying with the notion of creating a
+special \TeX\ edition of \emph{Trivial Pursuit}. There are those who
+contend that \TeX\ \emph{is} a trivial pursuit, but I will have
+nothing to do with this view. To assist in the creation of this game,
+and to tempt the likes of Waddington's, I will start to include
+examples of the questions in this column. The first question is in two
+parts. The first part is borrowed from the ACM 1994 Computer Bowl
+quiz: ``Only one person in all of computing's history has ever won
+both the ACM Turing Award for lasting technical achievement and the
+Grace Murray Hoppper Award for work done prior to reaching the age of
+thirty. Who is that person?''
+
+The second part is this: ``The Computer Bowl quiz was created and
+produced by the Computer Museum, Boston. What link does this have to
+the answer for the previous question?''
+
+\section{Dutch bearing gifts}
+I quickly snapped up my NTS \cd{} when it was offered through the
+group. I was motivated by a curious mixture of support for the
+efforts of another group, and a willingness to get tangled up in a
+flashily trendy technology, although
+I have to admit that I'm not yet convinced by \cd{} technology.
+%But I have to admit that I'm not yet
+%convinced by \cd{}. It seems to me like a suspect technology which is
+%only half way there, or one which has been rather over-hyped. While
+%the shiny disks can contain a fair amount of data -- 640 Mbytes --
+%this seems to me to be pretty inadequate for multimedia applications
+%which include still or moving pictures, and the access times for
+%random movements around the disk are appalling (almost as bad as World
+%Wide Web connections around the InterNet). It is fine for sequential
+%text when it is read in a linear fashion. In other words, pretty
+%boring stuff. However, as an archiving mechanism it offers some
+%potential, ignoring the extreme difficulty with which additional
+%material can be added.
+
+One advantage of the NTS \cd{} is the booklet
+which comes with
+it. Once you have installed the suite, and basically it wants to run
+from the \cd{} drive, you find that it is enormously configurable.
+Because of the many varieties of printers, screens and editors which
+are available in \dos{} systems, you could have many happy hours ahead
+of you getting things right. I get the feeling that it is assumed that
+you will like fiddling. There is no doubt that great effort went into
+this, and equally, that you can eventually install all the relevant
+bits and pieces. I wonder how you would manage to install something
+useful if you didn't want to use the 4\dos{} shell which is the
+default. Clearly the developers thought this an unlikely decision.
+They say ``One might object that using 4\dos{} batch files deprives
+the old-fashioned \texttt{command.com} users from the benefits of
+4\TeX. We happen to think that this would only be a mild punishment
+for not recognizing how good 4\dos{} really is.'' Well, pardon me!
+Oddly, they fail to mention that continued use of 4\dos{} involves
+payment of a shareware fee.
+
+Once you do get it installed, you still appear to have great power to
+customise the options the shell offers. However, I am still unclear
+how to change the drivers (you are provided with a variety of screen
+drivers and I really wanted the one which occupied least memory; this
+is not the default). I was also surprised that among the huge range of
+choices of formats you are offered, the simple \LaTeXe\ or plain \TeX\
+is not among them. It is rather like going into Macdonald's and trying
+to get a burger without the limp lettuce or the ketchup. In this case
+of the formats, the lettuce and ketchup is Babel.
+
+On the whole, I suspect the shell is about as good as you can get with
+\dos{}. It appears workmanlike. I'm afraid it does look dated though.
+Windows is here. The true \textsc{blu}e \TeX ie may resent it, and see
+it as a step towards perdition, but for many of us Windows is the
+least unacceptable face of the Intel chip's range of operating
+systems.
+
+But compared to PrimeTime's \cd{}, this is a joy. At least the NTG's
+offering has the advantage that you can browse it a bit like you
+browse \ctan. If there is a useful file there, you can find it and
+pull it out. The PrimeTime \cd{} is tarred and feathered (or zipped)
+so that you can't actually find anything unless you know where it is.
+It contains almost all the contents of \ctan, but nowhere does it
+actually give you the date of this snapshot. The sheer mass is
+daunting. And layered on the top of this is an assumption that \unix{}
+is the way the truth and the life. It makes a point about distributing
+source code: ``Binary-only distribution prevents recipients from
+modifying or learning from the internals of software.'' I have to
+confess that I'm not terribly interested in computer programs. I'm
+much more interested with what I can do with the program. The days of
+immersing yourself in the exciting details of source code should
+surely be passing. The terms `nerd' and `propellor-head' or
+`techno-weenie' spring to mind, almost unbidden. People you would
+prefer to avoid at parties. Like the ones who want to tell you the
+latest exciting details of \LaTeXe\ or \textss{dvips}. If I have to
+examine the internals to work out why \TeX\ inserts a skip at some
+particular point I'll drift silently to Quark Xpress.\footnote{In
+ passing, if I had put a fraction of the effort into Quark that I
+ have in \TeX\ and \LaTeX, I would be emminently employable at any
+ number of publishers. On the other hand, I would probably also have
+ a pony tail and an earring.}
+
+What is the basis for my rant? First, virtually all the discussion in
+the handbook is in terms of \unix{}. This is partly fair, since
+PrimeTime admit that their experience is almost wholly with \unix{},
+and does not really spread to other platforms. Until you actually look
+at the \cd{} itself (and yes, it is readable under \dos{}, Windows and
+the Mac), you don't realise that it might just be useful to you. There
+are the tools needed to unzip the many files on platforms other than
+\unix{}. I was mildly amused that the Windows unzip application came
+as a \texttt{.z} file itself (\ie\ \emph{zipped}), but since there is
+also a \dos{} executable, that is hardly insuperable. The Mac version
+of \textsf{unzip} came in two versions -- one a BinHex file, and the
+other a self extracting archive. The latter is the one that most of us
+would prefer. Those of us who enjoy the Mac tend to enjoy it because
+we don't have to mess around. We can get straight on with the real
+jobs. In order to use this archive you woud have had to dust down your
+copy of ResEdit and mess around changing file types: this is close to
+binary editing. It is not the sort of thing you do every day. So I
+BinHexed it, and there was the archive, which worked wonderfully.
+Except. There is always an except. Turning it loose on a part of the
+\cd, on a genuine \textsf{zip} file, it just wouldn't work until I
+realised that you had to copy the \textsf{zip} file to your hard disk
+and then unpack it. Otherwise you get unintelligible errors. This is
+clearly a failing of this particular implementation of \textsf{unzip},
+but it would have been `friendly' if the manual had pointed it out.
+After all, someone must have tested it all out, mustn't they? This
+means you have to waste disc space on the \textsf{zip}ped and unzipped
+files together.
+
+This aside, my main complaint is that to find anything you must first
+unzip the file you think it might be in. Since the unzipped files
+would amount to two gigabytes or so, you cannot really just unzip the
+whole archive and browse. Maybe I'm being uncharitable. After all, if
+you want a particular driver, you look for that driver, and not
+another one. Unzip it and off you go. No-one really wants to browse
+through all the bits of particular drivers, do they? But think,
+there's all that source to modify and learn from. I can hardly wait.
+%Does it have \LaTeXe? you ask. Clearly you haven't been paying
+%attention. It is the contents of \ctan. Therefore \LaTeXe\ is there,
+%and just where you would expect it. It is also the `current' version,
+%rather than the pre-release which the chronologically earlier NTG
+%\cd{} contained.
+
+The text of the handbook is
+largely taken up with technical details, but has a foreword
+George Greenwade, the \emph{emminence grise} of \ctan, a
+note on TUG by Sebastian `\emph{Il Presidente}' Rahtz (in
+uncharacteristically mellow and benevolent mode), and one of Kees van
+der Laan's idiosyncratic expositions entitled `What is \TeX\dots'.
+There is no doubt of Kees' enthusiasm. He writes at a frenetic pace
+which often leaves the tedious details of conventional sentence
+structure far behind. You will either find it exhilarating or
+debilitating. At times he seems capable of raising himself several
+feet off the ground purely by belief and pace alone. The ground looms
+up very large and unfriendly towards the end.
+
+I'm a little bemused by it all. In both cases, opportunities seem to
+have been missed. Or perhaps worse, \TeX\ is again cast in the light
+of the avid techno-whizz. Both of these offerings are just barely
+useful, and save themselves from consignment to one of the outer
+Hells. What is it that we should be doing? The contents of \ctan\ are
+undoubtedly convenient, but the compression of the PrimeTime disc does
+erect a barrier which is too high. Better to trim it mercilessly but
+make it more accessible (yes, I know there is a problem with depth of
+directories: \ctan\ goes deeper than the \cd\ format will allow). The
+NTG \cd, thanks to the shareware component, is just waiting to turn
+sour. The scrupulously honest will have difficulty creating an
+alternative integrated \TeX\ system. And anyway, it still isn't
+Windows! Time to get into the 90s, before the century ends. But at
+least it is possible to find useful files before you find them disc
+space.
+
+\end{Article}