By Leigh Andrews

A team from Newsclip recently took part in a tour of Caxton’s printing press in Industria, where Caxton’s community newspapers, as well as the Citizen, The Sowetan and the Financial Times are printed. The sheer size and sound of everything involved in the printing process, from the machinery to the giant reams of paper, is quite overwhelming!

Printing is a way of communication. In order to ensure the end-result is printed exactly as intended, each print job undertaken at Caxton Printers is accompanied by a work ticket. This is an envelope containing all the information pertinent to the specific job at hand, such as the progressive print outs and the all-important work number which assists in tracking details such as pagination and colour specifications. The progressive is a print out of what the final job should look like, based on newsprint as opposed to glossy paper, to avoid confusion further down the line.

Tour guide Rian Kruger took us through the entire printing process, beginning with the ‘starting point’ in pre-press. This is where the gatekeeper sits and carefully pairs pages which have been sent through an FTP system in PDF format. A proof onscreen shows the page make up and what the actual result should look like. Kruger informed us that newspaper printing uses a cold-setting system based on printing onto an aluminium plate which resembles a photograph negative, as opposed to glossy print outs and magazines which require heat-setting. He also explained the difference between tabloid and broadsheet sized newspapers, and how this affects the page-pairing process.

Development stage

Kruger used a rubber-stamp analogy to explain how the cold-setting process involves making a negative from the PDF onscreen. The impression from the negative is then burnt onto aluminium plates which have a slightly raised impression pressed into them. This is eventually rolled against a rubber blanket in reverse, like a rubberstamp. This stamp is then pressed against the eventual newsprint page to form the printed impression, the right way around again.

Litho printing involves water and ink. Kruger explained the process of burning the imprint from the negative onto the aluminium plate as follows: Paper is placed over all lights in the room to minimise the effect of UV on the plates and printouts, as UV is found in all light sources and has a damaging effect on the final product. The negative is fitted to a register plate, where it is attached via pin holes and lined up exactly. The negative is useful at this stage as it contains information regarding the pagination and colour settings. The negative is then vacuum-sealed under an aluminium plate, and a UV light burns the image onto the plate. The image is now burnt onto the aluminium plate, which hardens. The image area (clear on the plate) attracts ink, while the non-image area shows up black on the plate and attracts water. As ink is now in the non-image area, the plate resembles a negative of the final printout. The CTP or computer-to-plate process takes three minutes per plate.


Once the plate has the page imprint, it goes through an intensive process before it is ready for printing. This involves washing extra grime off the plate, drying the water and grime from the plate, adding a layer of gum which extends the ‘life’ of the plate, strengthening the imprint, and a heating process dries the plate again. The plate is then bent and cut to fit pins in the corners. Each plate can produce 350 000 newsprint impressions.

The press room... and others

In the press room, important factors are checked onscreen. One can check the balance of water and ink essential for litho printing, as well as whether the colour is in register. Tension rollers can also be adjusted to ensure the page to be printed on is held tight. This also shows where the page will fold.

The final step in printing involves using the actual ‘press’ that the printing process is named for. Here, the plates are placed against huge rolls of rubber where the inverted image is placed (the rubber stamp analogy). This rubber sheet is then rolled against a huge sheet of paper, and the page has completed its journey from PDF to printed sheet.

Enormous reels of newsprint paper, of all different sizes are kept on the floor. The now-printed paper is pulled through certain columns on what is known as ‘the kite’, which cuts the pages off as specified points. There’s double-sided tape on the reel to keep the pages in place. This system produces 60 000 copies per hour.

In the ‘water room’ we saw the huge quantities of water necessary for litho printing. A special ‘fountain solution’ of water is kept very cold in a tank, at a specified PH level of 4.2 to 5.5, which is slightly acidic. This cold water is what gives cold setting its name. Glossy printing, which involves heat setting, means the pages need to be heated and later cooled again through chill rollers, to ensure they doesn’t become brittle. In litho printing, the colder the water, the better the print. Water is therefore the heart of the cold printing process.

Caxton produces its own ink in the ink station. This is a specially heated room filled with huge drums of ink in the CMYK (cyan, magenta, yellow and keytone/black) colours, as well as smaller holders for spot colours such as bright orange, which may be used. The water room and ink station are both involved in the printing pressprocess.

Post press

Once the pages are printed and cut, they travel overhead on enormous carriages resembling railway tracks to the ‘inserts’ section. This is where all the loose advertising pamphlets, known as inserts, are placed into the finished product. Complete newspapers are carried overhead on machinery and opened at the centre point, into which the pack of inserts in placed. A ‘paper shaker’ then places the newspapers onto a machines that shakes the pages together in order to line the publication up nicely and ensure nothing juts out. Bundles of complete newspapers are then packed in clear plastic and sent to specific drop off points.

A most interesting journey, from digital start to printed end.