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From: Rowland McDonnell on 1 May 2010 10:41
Hugh Browton <useneth@**.not.uk> wrote:

> Rowland McDonnell wrote:
>
> > Hugh Browton <useneth@**.not.uk> wrote:
> >
> >> Rowland McDonnell wrote:
> >>
> >>> Hugh Browton <useneth@**.not.uk> wrote:
> >>>
> >>>
> >>> They are PostScript Printer Description files.
> >>
> >> Ah. OK, well something needs to be downloaded into the printers at printer
> >> switch on everytime, apparently.
> >
> > Not the PPD AIUI - that's used by the host computer to work out what the
> > printer can do. Bits of the PPD get sent to the printer as part of your
> > print job at print time - the PPD contains the header information needed
> > to drive the printer properly.
>
> Thanks for that - I certainly didn't know how it worked in any detail.

PostScript is an interesting beast. The `printer driver' in the case of
PS printers needs to do the following:

1) Communicate with the printer.

2) Find the header information for your printer kept in the PPD.

3) Find the PostScript file generated from your document.

4) Slap the header at the top of that, and send the whole lot to the
printer.

(I'm sure of step 4 because I've done it manually - dug out the header,
slapped it on using a text editor, sent the file to the printer
`manually', all on pre OS X Macs, following instructions that came with
OzTeX. Fascinating...)

The job of turning your `original' into PostScript is a standard job
that `just works' - it's one bit of software that does the same thing
for all PS printers.

Quite what the internal archicture of things is such as to generate that
PS file in the first place, I don't know. When I used LaTeX on Unix
back in the ooold days, we had `dvips' that turned DVI files (DeVice
Independent - printer-independent page descriptions of the final output)
into PS, and then you'd find the printer daemon to send it to the print
server and....

I suppose that translation into PS is the hardest part of the `PS
printer driver job' as such - but you see, because it's a standard fixed
job that's more or less identical on all computers and all printers
using PS, `they got it right years ago and it's still right'.
Sortathing.

Basically, if you're using a PS printer driver, you're avoiding all the
standard problems with printer drivers.

The print dialogue box on Macs that has all sorts of fancy printer
features available is derived from the PPD file in the case of
PostScript printers. Yep, all that stuff is worked out by the MacOS -
it reads the list of `things the printer can do' and gives you an UI to
those abilities, based on the entries in the PPD.

I did learn how to program in PS to a very minor extent, back at the
start of the 1990s... I had a need.

[snip]

> >>> btw, there's always the option of trying different versions of the
> >>> relevant PPDs, and also stripping out all that you don't need.
> >>
> >> I *could* do all that, but life's too short, and I've too much to do that
> >> interests me more than getting "known to be difficult" printers to work!
> >
> > Hmm - life's too short, so you intend to do something that'll take more
> > time and money than my proposal. How does that work?
> >
>
> My time is paid for by my clients - I can earn more working for them than
> sorting out a problem on a machine that has poor software - that I'm
> therefore "taking against". As in a "Why should I sort out the problems on
> bad stuff, I'll get good stuff" sort of way.

Mmm... My line is `it's all bad stuff, better the devil you know /if/
said devil's dealable-with'.

<shrug> Generally, it's not a bad idea to spend a while seeing if
whatever it is *is* dealable-with. If it takes half an hour and you've
got a workable fix (note it, in case you need it again) - well then,
that's saved you time and money compared to buying new, hasn't it?

If you get stuck and spend half a working day on the job, you'll
probably curse and tell youself you'll never bother wasting time like
that again. Or similar...

<shrug> again. What the hell - we all muddle through in our own ways.

[snip]

Rowland.

--
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From: Simon Dobbs on 1 May 2010 12:53
On Sat, 1 May 2010 15:41:38 +0100, Rowland McDonnell wrote
(in article
<1jhtk8j.9yf5p53m9nbdN%real-address-in-sig(a)flur.bltigibbet.invalid>):

> Hugh Browton <useneth@**.not.uk> wrote:
>
>> Rowland McDonnell wrote:
>>
>>> Hugh Browton <useneth@**.not.uk> wrote:
>>>
>>>> Rowland McDonnell wrote:
>>>>
>>>>> Hugh Browton <useneth@**.not.uk> wrote:
>>>>>
>>>>>
>>>>> They are PostScript Printer Description files.
>>>>
>>>> Ah. OK, well something needs to be downloaded into the printers at printer
>>>> switch on everytime, apparently.
>>>
>>> Not the PPD AIUI - that's used by the host computer to work out what the
>>> printer can do. Bits of the PPD get sent to the printer as part of your
>>> print job at print time - the PPD contains the header information needed
>>> to drive the printer properly.
>>
>> Thanks for that - I certainly didn't know how it worked in any detail.
>
> PostScript is an interesting beast. The `printer driver' in the case of
> PS printers needs to do the following:
>
> 1) Communicate with the printer.
>
> 2) Find the header information for your printer kept in the PPD.
>
> 3) Find the PostScript file generated from your document.
>
> 4) Slap the header at the top of that, and send the whole lot to the
> printer.
>
> (I'm sure of step 4 because I've done it manually - dug out the header,
> slapped it on using a text editor, sent the file to the printer
> `manually', all on pre OS X Macs, following instructions that came with
> OzTeX. Fascinating...)
>
> The job of turning your `original' into PostScript is a standard job
> that `just works' - it's one bit of software that does the same thing
> for all PS printers.
>
> Quite what the internal archicture of things is such as to generate that
> PS file in the first place, I don't know. When I used LaTeX on Unix
> back in the ooold days, we had `dvips' that turned DVI files (DeVice
> Independent - printer-independent page descriptions of the final output)
> into PS, and then you'd find the printer daemon to send it to the print
> server and....
>
> I suppose that translation into PS is the hardest part of the `PS
> printer driver job' as such - but you see, because it's a standard fixed
> job that's more or less identical on all computers and all printers
> using PS, `they got it right years ago and it's still right'.
> Sortathing.
>
> Basically, if you're using a PS printer driver, you're avoiding all the
> standard problems with printer drivers.
>
> The print dialogue box on Macs that has all sorts of fancy printer
> features available is derived from the PPD file in the case of
> PostScript printers. Yep, all that stuff is worked out by the MacOS -
> it reads the list of `things the printer can do' and gives you an UI to
> those abilities, based on the entries in the PPD.
>
> I did learn how to program in PS to a very minor extent, back at the
> start of the 1990s... I had a need.
>
> [snip]
>
>>>>> btw, there's always the option of trying different versions of the
>>>>> relevant PPDs, and also stripping out all that you don't need.
>>>>
>>>> I *could* do all that, but life's too short, and I've too much to do that
>>>> interests me more than getting "known to be difficult" printers to work!
>>>
>>> Hmm - life's too short, so you intend to do something that'll take more
>>> time and money than my proposal. How does that work?
>>>
>>
>> My time is paid for by my clients - I can earn more working for them than
>> sorting out a problem on a machine that has poor software - that I'm
>> therefore "taking against". As in a "Why should I sort out the problems on
>> bad stuff, I'll get good stuff" sort of way.
>
> Mmm... My line is `it's all bad stuff, better the devil you know /if/
> said devil's dealable-with'.
>
> <shrug> Generally, it's not a bad idea to spend a while seeing if
> whatever it is *is* dealable-with. If it takes half an hour and you've
> got a workable fix (note it, in case you need it again) - well then,
> that's saved you time and money compared to buying new, hasn't it?
>
> If you get stuck and spend half a working day on the job, you'll
> probably curse and tell youself you'll never bother wasting time like
> that again. Or similar...
>
> <shrug> again. What the hell - we all muddle through in our own ways.
>
> [snip]
>
> Rowland.
>
>

forgive my ignorance, and my inability to cut a longish thread, but I thought
that Macs had now lost postsript as the printing file format of preference in
favour of the acrobat file format.

From: Rowland McDonnell on 1 May 2010 13:31
Simon Dobbs <simondobbs(a)froglet.net> wrote:

> Rowland McDonnell wrote
[snip]

> forgive my ignorance, and my inability to cut a longish thread,

Ignorance is easy to understand and needs no forgiveness; but - erm -
how come you can't cut? Select unwanted text, delete it, then replace
with [snip] if you want to be polite and show where you've removed
stuff.

Just normal text editing functions.

> but I thought
> that Macs had now lost postsript as the printing file format of preference in
> favour of the acrobat file format.

Erm. It's not like that. PDF isn't sent directly to yer typical
printer. It was designed as a document file format for display on
computers /which can also/ be turned into PS very easily for printing.

PDF - the file format used by Adobe Acrobat - is closely related to PS.

Some printers speak PDF directly (basically, they turn to PDF into PS
inside the printer. Or so I've gathered - I might be wrong about that
degree of detail).

Most don't.

The printing file format used is therefore not PDF - not in the case of
most printers.

Typically, the printing file format is something like PCL 3 (HP
inkjets), PCL 5 (HP laser printers), PostScript (often PS emulation - as
in HP laser printers), or whatever the hell Epson and Canon printers
`speak'. Etc.

btw, PDF generated by `print to PDF' using the MacOS X print dialogue
box is not very good PDF. It's worked okay when I've used it - but I
get smaller PDFs directly from pdfTeX, which I'm told are technically
more elegant but I can't tell myself.

Rowland.

--
Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org
Sorry - the spam got to me
http://www.mag-uk.org http://www.bmf.co.uk
UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Simon Dobbs on 1 May 2010 14:39
On Sat, 1 May 2010 18:31:02 +0100, Rowland McDonnell wrote
(in article
<1jhtrn7.1arevns6zjo7bN%real-address-in-sig(a)flur.bltigibbet.invalid>):

> Ignorance is easy to understand and needs no forgiveness; but - erm -
> how come you can't cut? Select unwanted text, delete it, then replace
> with [snip] if you want to be polite and show where you've removed
> stuff.

sorry Rowland, when I wrote 'inability' I was implying 'can't be bothered'.

Yes I am a lazy and bad example of the human species, and I smell, but,
frankly, I don't give a damn.

From: Simon Dobbs on 1 May 2010 14:39
On Sat, 1 May 2010 18:31:02 +0100, Rowland McDonnell wrote
(in article
<1jhtrn7.1arevns6zjo7bN%real-address-in-sig(a)flur.bltigibbet.invalid>):

> Erm. It's not like that. PDF isn't sent directly to yer typical
> printer. It was designed as a document file format for display on
> computers /which can also/ be turned into PS very easily for printing.

You are right, of course. Postscript does not normally come into the equation
nowadays, however.

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