Phototypesetting with the Berthold ‹diatype›


Today fonts are just digital files, but 50
years ago, a font could look like this: A glass disc with the letters as inverted images
on them. And one of these discs could replace all the type cases of metal type in one of
these cabinets you can see behind me. And today I am at the printing museum Pavillon-Presse
in Germany and we will take a look at the machine in which such a font was being used. When we think about typography and type-setting
today, two techniques usually come to mind: the first is letterpress, used since the days
of Gutenberg in the 15th century. You have a physical letter with a raised surface – you
put ink on it and then you press the letter on paper to create a print. But today we usually
use desktop publishing, where the letters are stored as a mathematical outline description. But between letterpress and desktop publishing
there was another technique that is often forgotten: phototypesetting. It was used from
the middle of 20th century until the 1980s and in many regards it acted as a bridge technology
between letterpress and desktop publishing. »The Fotosetter was the first successful
phototypesetting machine to produce type on photographic paper or film in quantity. A
camera replaced the metal pot in the old line-casting machine. Type characters were now photographed
individually instead of being cast in metal. The conventional Linotype mould or mat was
replaced by a negative.« Phototypesetting basically works like creating
photographic prints from a negative. There is a light source, a negative and a light-sensitive
paper or film. And in the case of phototypesetting the negative is just an image of a letter
and you expose one letter at a time until the text is complete. Phototypesetting fonts could have very different
shapes and sizes, like a long plastic strip or a small plate with the letters in a table
layout. But machines like the Diatype used discs, because they could easily be shifted
and rotated inside a phototypesetting machine to reach a certain letter. The Diatype can only hold one font at a time,
so when we want to switch the font, we have to open the backside of the machine and replace
the font manually. These fonts can hold 190 characters, so the possible character set
is similar to the 8 bit encodings that were used later in the early days of desktop publishing.
The letters on the discs have a size of 12 points, but the machine can scale the letters
between 4 and 36 points. And that was a significant change in comparison to letterpress, where
you needed a set of physical letters for each size you wanted to use. Before we can start typesetting with the Diatype,
we first have to put in the photographic film or paper. To to that we open the flap at the
front and remove a cassette which hold the film or paper. We take it into a darkroom,
so the film or paper doesn’t get exposed to daylight, but once the paper or film is
in the cassette and the cassette is closed again, we can then insert it into the machine
in daylight. So the light will travel from the back of
the machine; through one letter of the font disc; then through lenses in the device, which
will take care of scaling, spacing and focussing, and then it will hit the photographic film
or paper through this opening of the cassette here. The cassette will move from left to
right inside the machine and the drum inside the cassette is rotated to reach any point
on the film or paper. Of course the size of the cassette limits the size of the columns
you can create, but this machine wasn’t meant to set things like newspapers or large
books anyway. It was used for ads, for forms, tables and things like that. To pick a letter there is a plate on the front
of the machine, which shows all characters of the font. The plate can easily be swapped
if we want use a font with a different character set. And then we just pick a line with a handle
on the left side of the machine. This moves the disc up and down. The pistol grip, used
with the right hand, rotates the disc and selects a specific letter on the selected
ring of the font disc. And a simple push of the button then automatically exposes the
selected letter on the film and moves the film according to the width of the letter
in the selected type size. Exposing one letter takes roughly one second and so an experienced
operator can set thousands of characters per hour. And once the text is complete, the film
or paper is then developed in a darkroom and can be used to finish the page layout and
then a plate for offset printing is usually created. With such a phototypesetting machine, the
operator has full control over type size, line spacing, tracking, the spacing of consecutive
letters and there is even a tabulator function to set tables more easily. You could also
move the drum with the film or paper around freely to set more complicated things like
formulas. And the machine, the type and the standing matter needed a lot less space than
what was required for metal typesetting. So there were quite a few advantages of machines
like the Diatype, but you might have already noticed a serious drawback: this is not a
What-You-See-Is-What-You-Get device, because frankly, while using it, it doesn’t show
you anything at all. The scales on the machine can tell you where you are on the page, but
that’s basically it. So you had to very carefully plan and measure your text layout
in advance and then you had to be equally careful while typing the text with this machine.
And so once desktop publishing came along, those machine very quickly came out of use.

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9 thoughts on “Phototypesetting with the Berthold ‹diatype›

  1. Thank goodness for computers! Dark rooms and not being able to look at what you're doing is not fun at all! For some reason, colleges require old-fashion film photography for some programs, even though the technology's expensive, terribly error-prone, and a huge hassle! I'm so glad the kids born today won't have to deal with all the headache that this technology brought with it because the stubborn old people should have moved on by then.

  2. The first phototypesetting machines used a film type font, as shown here. More advanced ones were computer driven. The operator was able to set type using alphanumeric commands that controlled line length, leading, font, point size, kerning and other parameters. A font disk, similar to the one shown on this video would spin, and a flash tube would expose the paper. An encoding strip along the edge of the disk was used to synchronize the flash tube to fire when the proper character was in the proper position. Stepper motors, gears, and a carriage moved the exposing lens along the width of the paper. They also operated the zoom lenses to produce the range of type sizes. A set of rollers fed the paper (which came on rolls of various length and widths, generally 8 inches wide by 100 feet long) into the canister with each line feed. When the job was complete an end of job command would run 6 inches of paper into the canister The paper was cut and then fed through a processor that ran the paper through baths of developer, fixer, wash, and sometimes dryer. A machine, called a waxer, applied melted wax to the back of the paper galleys. They were then "pasted up" on boards from which a photographic plate was produced, that was used on an offset press.

    At the end of the phototypesetting era, a cathode ray tube was used to image the paper. It provided a type medium that was unaffected by dirt and wear, unlike the film disks. Since the characters were produced as vector images their geometry from standard could be squeezed, expanded, and otherwise modified. For typographers the ability to manipulate the geometry of a type character was a magical enhancement to the technology. It also gave rise to some not very pretty type.

    It is amazing to me that, at least in the U.S., these phototypesetting machines have virtually disappeared. A functioning Varityper, CompuGraphic, or Merganthaler machine is not to be found.

  3. Thanks for the video. It took me back to my apprenticeship. One thing worth noting is:– if one wanted the text to be centred, we had to set it blind to begin with, then calculate how much to indent each line. And justified text was even harder. But the scalpel often came in handy.

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