Mander-Kidd Limited was one of the country’s largest manufacturers of printing ink. The Heath Town factory had the most up-to-date equipment of its kind, and produced all kinds of printing ink for most of the printing processes that were in use at the time. Inks were produced that were suitable for use with all kinds of paper and boards, metal foils, and plastic films. Ink is a complex medium, with exacting requirements. Colour consistency is essential, across a whole range of colours, and uniformity, so that the same result is achieved each time. Ink must not dry in the printing machine if left overnight, but has to dry in a split second on paper. Some inks are as thick as putty and others have to flow like milk.

The Heath Town factory.

Ink also had to keep-up with advances in technology. New machines, materials and processes were constantly introduced, so a large amount of investment had to be put into research and development. Well-equipped and sophisticated laboratories were essential, along with qualified and experienced laboratory staff.

Raw materials were imported from many countries including Africa, Brazil, Canada, Central America, India, Korea, the Middle East, the Philippines, Scandinavia, Spain, and the United States. The all important colour pigments came from Britain’s coal mines. They were derived from the distillation of coal tar, with the careful addition of controlled quantities of rare metals such as tungsten and molybdenum. Other important raw materials were carbon black, a product of petroleum, and titanium, zinc and lead which were used to produce white ink.

One of the raw material stores.

Samples of all of the materials were taken on arrival, and thoroughly examined and tested in the laboratory before being released to the factory. This was essential to ensure that high standards of quality and consistency could be maintained. Careful stock control was also important to make sure that adequate stocks were available when supplies were interrupted due to unforeseen circumstances.

Inspecting one of the varnish pots.

One of the most important ingredients is varnish, which is the basis of the ink. It carries the colour, determines the ink's behaviour in the printing machine, and the quality of the ink film on the printing surface.

It was made in the varnish plant using the most up-to-date techniques. Manders produced varnish for over two hundred years, during which time the process considerably changed.

Originally heated linseed oil or semi-drying vegetable oil was used with a natural gum such as Congo Copal, which had been previously treated to render it soluble in the oil. This was replaced with a range of vegetable and other oils that were stored in a large 'tank farm'. Quantities of chemically pure compounds were added to the oil, and the mixture was heated in a closed vessel, which could hold about two tons of raw ingredients. A batch would usually be finished in less than 24 hours, during which time the temperature was accurately monitored.

The tank farm where 50,000 gallons of oil was stored.

Throughout the process, by-products such as water were continuously removed, to leave a synthetic varnish with the precise qualities that were required for the ink. Periodically samples were taken, and the viscosity measured. When it was exactly right, the varnish was piped to a set of coolers, and through a large filter press to the storage tanks.

To produce the ink, pigments were thoroughly blended with the varnish, to which driers and reducing mediums were added in correct proportions. The ingredients were then thoroughly mixed in powerful mixing machines that could each handle half a ton at a time. The machines occupied a large part of the floor space at the factory.

Emptying one of the mixing machines.

When mixed, the ingredients were taken to the grinding mills which dispersed the minute pigment particles evenly throughout the varnish medium. The mills had three water-cooled, electrically driven, polished steel cylinders that were geared, so that the second cylinder rotated slightly faster than the first, and the third cylinder rotated faster again. The degree of 'nip' between the cylinders was carefully adjusted according to the kind of ink being made.

Part of the main mill room showing some of the three roll mills.

The operators would pass the ink through the mill for anything up to eight times depending on the type of pigment, and the requirements of the formula. A sample would then be taken to the testing room to be compared with a standard sample. The properties, including colour and consistency, tackiness and drying speed were examined by an expert, and when correct, the batch would be measured into cans, which were sealed and labelled for despatch. Every can was stamped with a code number so that the whole history of its manufacture could be traced.

A batch of ink nearing completion on a Torrance three roll mill.

The company also produced batches of special inks that were different in some way to normal inks, and catered for customer’s unusual requirements.

They were often produced in small quantities from a mixture of standard products, sometimes with additions, and were ground by hand on mixing slabs or benches.





Hand mixing a special colour on a slab.

One of the laboratories with some of the large collection of pigment standards in the foreground.

The firm’s laboratories were an essential part of ink manufacture. Every stage of production was carefully monitored and subjected to stringent physical and chemical tests. Laboratory staff also prepared formulae for new inks, and looked after special matchings to customers' orders, and matchings to paper. The best equipment was used, including extremely accurate electrically controlled balances, devices for measuring colour by spectrum analysis, viscometers, miniature grinding mills, and a great variety of chemical apparatus.
There was also a light fastness testing machine (seen on the left) which could subject sample panels to the equivalent of several months' exposure to sun and rain in a few hours, and an automatic machine for determining the printed film's resistance to abrasion.

There were also machines to test every physical and chemical property of ink so that the result could be recorded in mathematical terms.

Testing the viscosity of a new batch of varnish in a thermostatically controlled bath.
A carton ink being tested for abrasion resistance with a Sutherland rub tester.
Producing a trial quantity of ink on a miniature three roll mill.
A continuous programme of research into possible new materials and processes was undertaken. New papers and other printing surfaces were minutely examined, and a close eye was kept on developments in the printing trade so as to find a way of meeting future requirements in advance.

One of the research laboratories.

The factory also had a printing department, equipped with a full range of printing machines.

The letterpress section had a flatbed Miehle, Heidelberg and Arab platens, and a Soldan.

The offset section had an A.T.F. Chief and a Rotaprint, and the gravure and aniline section had a Chambon.

The machines allowed the operators to test the performance of inks under normal workshop conditions.




A proofing press in the machine room.

The letterpress section in the printing department.

After manufacture, the ink was quickly and safely distributed to printers. Mander-Kidd was ideally situated in the centre of the country, and able to service all areas through the London factory or one of nine branches. All of them carried large stocks of inks and had their own delivery service. Some of them were also able to mix special matchings on the spot, and the London factory had manufacturing and laboratory facilities to cope with urgent orders.

UK factories and branches.

There were also three factories in South Africa, one in Rhodesia, another in Australia, and over sixty agents throughout the world. Mander-Kidd offered a service that was second to none. It was greatly appreciated by the vast number of customers who regularly used the products.

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