[comp.dcom.fax] Fine mode in Group III faxes

jonathan@cs.pitt.edu (Jonathan Eunice) (04/07/91)

I read in the May, 1991 MacUser that Group 3 faxes have a Standard
resolution of 203x98 dpi, and a Fine resolution of 203x196 dpi.  The
sample shown (p. 107) makes Fine look *much better* than Standard.  Do
most standalone fax machines support the Fine resolution?  I've
received a fair number of faxes, and I can't recall any that looked
anywhere near as good as MacUser's example.  Is this just because no
one is using Fine mode, or is it because it hasn't been available on
many fax machines?

dandrews@bilver.uucp (Dave Andrews) (04/09/91)

In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
>sample shown (p. 107) makes Fine look *much better* than Standard.  Do
>most standalone fax machines support the Fine resolution?  I've

Fine is supported most everywhere, but it takes twice as much time to
send a fine page as a standard resolution page.  There are a few of
us pathological types that use Fine regularly because of the quality
improvement, but not many.

In my mainframe-to-fax application (I'm using a couple of Connection
Coprocessors), I use standard resolution all the time because the
character generators in the card contain low-res fonts.  Fine doesn't
buy me diddly in that particular environment.

- David Andrews     tarpit!bilver!dandrews

mikes@gammafax.gammalink.com (mike spann) (04/10/91)

In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
>I read in the May, 1991 MacUser that Group 3 faxes have a Standard
>resolution of 203x98 dpi, and a Fine resolution of 203x196 dpi.  The
>sample shown (p. 107) makes Fine look *much better* than Standard.  Do
>most standalone fax machines support the Fine resolution?  

Fine resolution is technically an option for Group 3 fax machines.  As is
9600, 7200 and 4800 bps operation.  In practice, you will have to look
far to find a machine that does not have fine mode or the higher speeds.

Sending a fax from a fax machine in fine resolution 'usually' requires the
user to press a button on the fax machine before sending each fax.  I say
'usually' because some fax machines do allow you to set fine mode as the
default.  Most have standard resolution as the default, requiring the
sender of the fax to want to spend twice as much to send the fax with higher
resolution.

Finally, CBF (Computer Based Fax) will look significantly better than any
fax machine generated fax.  CBF products generate images for the resolution
of a fax machine and treat the remote fax machine like a remote printer.
Sending computer based information with a regular fax machine requires you
to print the information to paper, then scan it into the fax machine.  This
almost always looks much worse than sending it directly from the computer.

mike


-- 
Michael Spann                           mikes@gammalink.com
Voice:  +1-408-744-1430			Fax:    +1-408-744-1549
UUCP:   ...!uunet!gammafax!mikes   	CIS:    73747,441

dww@stl.stc.co.uk (David Wright) (04/10/91)

In the referenced article mikes@gammafax.UUCP (mike spann) writes:
#In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
#>I read in the May, 1991 MacUser that Group 3 faxes have a Standard
#>resolution of 203x98 dpi, and a Fine resolution of 203x196 dpi.  The
#>sample shown (p. 107) makes Fine look *much better* than Standard.  Do
#>most standalone fax machines support the Fine resolution?  
#
#Sending a fax from a fax machine in fine resolution 'usually' requires the
#user to press a button on the fax machine before sending each fax. 
#... Most have standard resolution as the default, requiring the
#sender of the fax to want to spend twice as much to send the fax with higher
#resolution.

I don't think any of the people who use the FAX machine in our office use
any of the options, including 'fine'.   It's generally assumed that the
machine is automatic and that if your document needs to be sent in 'fine'
mode the machine will automatically decide that. I don't think it ever has :-)

Remember that most people don't want to know about anything more complicated
than ON/OFF and maybe dialling a telephone number - that's why FAX has taken
off in such a big way, whereas electronic mail and other more IT-intensive
communications systems have grown more slowly, outside of the technical
community at least.   This is very frustrating to those of us in the IT
industry who know how much 'better' such methods are - but in fact it's our
fault for failing to produce systems which are genuinely user friendly.

I cite as an example trying to persuade a non-profitmaking organisation I am
involved with to communicate with its area contacts by email (or at least
computer-based FAX) instead of FAX, so that press releases and artwork
examples can be edited and re-used rather than having to be re-typed/
redesigned locally.    The answer I got was "Of course that would be better
if we could do it, but most of the help we have in the office is from
volunteers who come in on a very ad-hoc basis and there's no way we can
provide such people with computer training - they can mostly use a FAX
machine though".

#Finally, CBF (Computer Based Fax) will look significantly better than any
#fax machine generated fax.

True.  Especially at 'fine' resolution.   Though personally I'm currently
using 'normal' again as the result is perfectly readable and the call time
(and thus cost) is less.    Which is why even those who know what the 'fine'
button actually does do not usually use it.    Roll on FAX on ISDN (one
day!) where the 64K data rate should make 'fine' cost only pennies more even
on long distance calls.

Regards,          "None shall be enslaved by poverty, ignorance or conformity"
        David Wright             STL, London Road, Harlow, Essex  CM17 9NA, UK
dww@stl.stc.co.uk  <or> ...uunet!mcsun!ukc!stl!dww  <or>   FAX: +44 279 432734
<or> /g=David/s=Wright/org=STC Technology Ltd/prmd=STC plc/admd=Gold 400/co=GB

hrs1@cbnewsi.att.com (herman.r.silbiger) (04/10/91)

In article <1281@gammafax.gammalink.com>, mikes@gammafax.gammalink.com (mike spann) writes:
> In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
> >I read in the May, 1991 MacUser that Group 3 faxes have a Standard
> >resolution of 203x98 dpi, and a Fine resolution of 203x196 dpi.  The
> >sample shown (p. 107) makes Fine look *much better* than Standard.  Do
> >most standalone fax machines support the Fine resolution?  
> 
> Fine resolution is technically an option for Group 3 fax machines.  As is
> 9600, 7200 and 4800 bps operation.  In practice, you will have to look
> far to find a machine that does not have fine mode or the higher speeds.
> 
> Sending a fax from a fax machine in fine resolution 'usually' requires the
> user to press a button on the fax machine before sending each fax.  I say
> 'usually' because some fax machines do allow you to set fine mode as the
> default.  Most have standard resolution as the default, requiring the
> sender of the fax to want to spend twice as much to send the fax with higher
> resolution.
>

Since the T.30 protocol allows for renegotiation after evry page, you can go
from normal mode to fine mode between pages.  This is useful if you have only 
one or two pages in  a document that really need the higher resolution, since
invoking high resolution increases transmission time.

Herman Silbiger 

hrs1@cbnewsi.att.com (herman.r.silbiger) (04/10/91)

In article <1991Apr9.132236.21891@bilver.uucp>, dandrews@bilver.uucp (Dave Andrews) writes:
> In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
> >sample shown (p. 107) makes Fine look *much better* than Standard.  Do
> >most standalone fax machines support the Fine resolution?  I've
> 
> Fine is supported most everywhere, but it takes twice as much time to
> send a fine page as a standard resolution page.  There are a few of
> us pathological types that use Fine regularly because of the quality
> improvement, but not many.

The use of fine mode does not double transmission time if the machine is using
the optional 2-dimensional coding.  In 2-dimensional coding, the coding is
of a line is dependent on the change from the previous line, with (for T.4) a
maximum window size of 4 lines.  Thus, when you increase resolution, lines get 
to be more alike, and the coding is more efficient.

With the optional T.6 encoding, there is no limit to window size, which is the
principal reason for its increased efficiency.

There are similar gains in efficiency when going from 200x200 ppi to 300x300 ppi.

Herman Silbiger

gallo@dtrc.dt.navy.mil (Gallo) (04/11/91)

<previous_post_refers to ISDN fax

Yes, but then you're talking Group 4 if you want to put it
on a digital line. You get a page of standard resolution in
2 seconds or so. Right now the machines start out at
around $15,000 U.S.  Canon facs people told me that the
German post office just bought a slew of these for_their
fax network.

oeschi@netmbx.UUCP (Johann Deutinger) (04/15/91)

In article <1991Apr10.144829.4271@cbnewsi.att.com> hrs1@cbnewsi.att.com (herman.r.silbiger) writes:
>In article <1281@gammafax.gammalink.com>, mikes@gammafax.gammalink.com (mike spann) writes:
>> In article <10335@pitt.UUCP> jonathan@cs.pitt.edu (Jonathan Eunice) writes:
>> >I read in the May, 1991 MacUser that Group 3 faxes have a Standard
>> >resolution of 203x98 dpi, and a Fine resolution of 203x196 dpi.  The
[stuff deleted]
>
>Since the T.30 protocol allows for renegotiation after evry page, you can go
>from normal mode to fine mode between pages.  This is useful if you have only 
>one or two pages in  a document that really need the higher resolution, since
>invoking high resolution increases transmission time.
>
If the pages don't contain much information, the additional time required
for renegotiating the resolution (maybe even twice if you send pages
standard-fine-standard) may be as evil as sending the whole thing in
fine resolution.

If you send a short memo, the transmission time of the document is by far
not twice the time in fine resolution, compared to standard resolution
because the initial handshake (T30 phase B) takes several seconds by itself.

Of course, if you use a faxcard which uses the same character generator
for standard and fine resolution (in that case doubling every scanline)
there is no reason not to use standard resolution all the time. If your
faxcard has a separate (better looking) character generator for fine
resolution or if you create faxes using an MS-Windows driver you might
want to use fine resolution for important business documents where the
appearance of the fax could have some influence on the receiver.


-- 
oeschi@netmbx.UUCP     | Johann Deutinger
voice +49 30 396 50 21 | Ferrari electronic GmbH (.. no, we don't sell cars)
fax   +49 30 396 80 20 | Beusselstr. 27  -  1000 Berlin 21  -  FRG