[GreenKeys] Telephoto machines?

[Richard Knoppow]

      Possibly Finch Telecommunications    See
http://www.nytimes.com/1990/11/17/obituaries/william-finch-93-held-many-patents-in-radio-technology.html
    For an obit of William Finch who was a pioneer in the development of 
facsimile machines.
      There is a good section on early machines in _Radio Engineering 
Handbook_  Forth Edition,  Keith Henney ed. (1950) McGraw-Hill p.1050 ff.
      I did a casual Google search but couldn't find anything definite 
on the old machines.   I think at least some machines worked on voice 
grade regular phone lines and, without modern digital compression 
methods, would have been very slow.   AP may have used the trade mark 
Telephoto but Wirephoto was also common in picture credits and was 
probably closer to a generic term.
      I think the Japanese were mostly responsible for modern FAX 
because it has great advantages for a pictographic language.

On 6/27/2015 10:00 PM, David I. Emery wrote:
> On Sat, Jun 27, 2015 at 07:25:20PM -0500, Jim Haynes wrote:
>> The WW-II era AN/TXC-1 was a photo-quality machine used by the military.
>> I imagine it was derived from a civilian machine, but I don't see anything
>> in the tech manual that identifies the supplier.
>>
>> There was, I believe, a company called Times Facsimile.  Nick England's
>> web site mentions some fax equipment used by the Navy and made by Times
>> Facsimile.  I wonder if that was a subsidiary of the N.Y. Times.  There
>> was also a Times Wire & Cable Co. that made coaxial cables among other
>> things.
> 	I played around a bit in the early to mid 60s when in HS with
> some old Times photofax gear of the sort that was once used for
> wirephoto distribution.   Used a fancy neon lamp (called a crater lamp
> for the bowl shape of the electrodes) focused with a microscope
> objective lens on a metal drum around which one wrapped sheets of
> photographic large format film (or photo paper).   The drum was turned
> by a special phonic wheel motor driven by a big AC power amplifier from
> a tuning fork oscillator (or in my case a VCO locked to a reference) and
> a lead screw mechanism moved the drum along its axis past the lamp and
> lens.
>
> 	There were various standards in use for these things at the
> time, early ones were 60 RPM drum speed, later they went to 120 RPM
> IIRC.
>
> 	The lead screw pitch/rotation rate also varied as different fax
> systems used different scanning density (something called the "index of
> cooperation".
>
> 	The crater lamp was designed to have a suitable known curve of
> light output versus drive voltage and current... and with the correct
> electronics driving it could accurately reproduce a gray scale over a
> couple of decades of optical density at least.
>
> 	The rotation rate of the synchronous phonic wheel motor was
> controlled by the AC drive frequency which was derived from a tuning
> fork or crystal standard as the line frequency is actually remarkably
> unstable and off much of the day... and the phasing of the drum rotation
> was controlled by a mechanical slip clutch released by a magnet driven
> from the incoming signal before a photo transmission which carried a
> once per rev sync pulse designed for this purpose.
>
> 	The actual line signal was a 1500 or 1800 Hz AM modulated
> carrier, with start stop and control and phasing info on other lower
> frequency tones.
>
> 	These early machines were pretty manual, one loaded the film in
> a dark room and waited until the start tones and phasing occurred and
> started up the drum - then engaged a clutch to start the lead screw when
> actual image info was transmitted.   An operator had to be present to
> change the film (and develop it) and start up a new reception.
>
> 	There was sometimes actual speech audio on the wireline circuit
> announcing specific image transmissions I understand... the machines I
> had had a monitoring speaker for this.
>
> 	Later generation machines used rolls of dry photo paper fed past
> a mirror scanning mechanism... and could print multiple photos on the
> paper as it went past in one long roll.   I believe there were also film
> machines of that era that did this on rolls of film that could be later
> developed and used to create halftones.
>
> 	I remember seeing the roll of paper machines in newspapers and
> TV newsrooms in the 60s/70s... I believe the paper prints were mostly
> for editorial use, and they actually used film for creating the printing
> plates/halftones so both were sometimes captured.
>
> 	And I know in addition to the actual dry photo process there
> were some machines used for this that used wet electrolytic processes
> similar to the ubiquitous Alden reddish brown images used universally in
> weather forecast offices and aviation FSS and other pilot briefing
> facilities for weather maps.   I think one maker of these was Fairchild,
> but memory fades with age...
>
> 	AM transmission (both originally DSB, and later I believe a VSB
> system) on voice grade circuits was standard for newspapers and TV
> stations - but there was a good bit of HF radio wirephoto transmission
> to overseas subscribers that used FM instead.   Much of that was 60 or
> sometimes 90 RPM... rather than 120 RPM.
>
>> Ah, yes, I see a web page www.hffax.de/history/html/facsimile_makers.html
>> Perhaps answers all the questions.
>   
>> There were fax companies Alden and Hogan Faximile, but I don't know if
>> they made photo-quality equipment.
> 	Alden more or less owned (at least in the USA) the market for
> machines used to distribute weather maps and later made a lot of
> machines used for displaying APT and WEFAX weather  satellite photos as
> well.    These worked with a spring loaded helix wire wrapped around a
> rotating drum that formed a contact point with a thin ribbon of
> stainless steel on the other side of the paper (the paper was pressed
> between the helix wire and the steel ribbon blade by springs and pulled
> past them by motorized rollers).
>
> 	The paper was wet, and soaked with an electrolyte and current
> was driven through it between the blade and the helix, which caused a
> chemical reaction with iron from the blade that produced the reddish
> marks.   Later chemistry made bluish markings toward the end of the
> Alden era.
>
> 	Alden machines were sometimes used for other things, but the
> great majority of them were used at virtually every airport and weather
> forecast office and flight service station in the US and most major TV
> stations and many universities.   I don't believe they tried very hard
> for high quality photo grade image reproduction... though there were
> other electrolytic machines and chemistries that were pretty good.
>
> 	Signaling for the weather maps was originally similar to the
> early wirephotos but eventually was converted to a compressed digital
> format called Difax sent over early digital voice grade modems and later
> over VSAT satellite circuits - until the whole infrastructure was
> replaced with computer imaging and electronic weather maps in the 1990 -
> now all of this stuff is high speed IP over a geo satellite broadcast
> in modern digital image formats (and of course over the Internet as
> well).
>
> 	I have never seen a Hogan machine... or know much of anything
> about their markets.
>
> 	I don't know at what point press wirephotos were converted to
> other forms of transmission (56 kbs) but I do remember reading that a
> color higher quality faster technology was introduced sometimes in the
> 80s or 90s.  I do, however, know that at least some of the modified AM
> analog voice grade wireline stuff was around into the mid 80s more or
> less... with VSB modulation and more sophisticated signal structure
> IIRC... and maybe 240 RPM.
>
> 	Recently almost all of this wire service stuff is now
> distributed by Internet... in the usual Internet photo formats along
> with the actual wire copy that used to be printed on TTYs... and of
> course now a lot of video clips.    The various photo encoding and file
> formats are more or less the same as used for other images on the net.
>
> 	Satellite broadcast transmission of digitized news video clips
> was common until very recently but most of this has also migrated to
> on-demand cloud servers rather than geo satellite broadcasts.	
>
>>   Then Western Union spent tons of
>> money on fax development, but I don't know if they got into photo quality.
>> They were more interested in fax as a way of handling messages.
> 	Aside from news wirephotos and weather photos the other major
> customers for photo quality fax back then were the military and the
> intelligence community... there wasn't a whole lot of use of electronic
> image transmission for other civilian purposes - partly because images
> took a lot of bandwidth which was very costly back then... and compression
> technology was in its infancy and expensive and complex for the era.
>
> 	Of course the 70s and early 80s saw a huge explosion in the use
> of digital fax for messaging... over regular POTS lines.
>
>
>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL