Paints, Dyes and Inks
Paints
Paint is a blanket term for a wide range of materials, the ingredients of which are many and varied. Prior to the general introduction of synthetic materials in the late 1950's paint was a pigment, usually a fine powder, mixed with a 'vehicle' liquid, usually a vegetable oil. Linseed oil (obtained from the seeds of the flax plant) was the most common, but fish oils and more recently petroleum oils have been used as well.
Pigments are coloured powders which are not soluble in water (dyes are colours which are water soluble). Important pigments to the railways included Lead chromate, the yellow which featured on the early railway coaches in spite of being somewhat poisonous. This was replaced by Indian Yellow, a double nitrate of cobalt and potassium not affected by hydrogen sulphide gas, which made it useful in the days before the Clean Air Act of 1955.
Lead sulphate is used to make a blue or blue-grey pigment and it has a protective role when used in metal 'primer' paints. Blue (synthetic Lapis Lazuli) was made by heating china clay with sodium sulphate and charcoal. Prussian blue is one of the colours based on Iron Blue (Iron Ferrocyanide) and iron oxides form the basis of a range of reds including yellowish sienna, brownish burnt sienna and Indian red (also called Iron Saffron). Synthetic Iron oxide yellow (hydrated ferric oxide) holds it colour better than the naturally occurring yellow oxides such as ochre. Iron in the from of powdered Magnetite ore, which occurs in various forms but basically consists of iron oxide, was also used to make black paint and this material was sometimes called 'black rouge'. White paint was one of the more difficult products to develop and the earlier whites, based on white lead, blackened on exposure to the sulphur in the atmosphere of the coal powered industrial areas. White lead usually refers to lead carbonate but the term is also occasionally used for lead sulphate and lead silicate basic. Zinc oxide white pigment was developed in the 1840's and was subsequently widely used by railway companies for wagon markings as it did not blacken on exposure to the polluted air.
Varnish consists of a resin (to give a gloss finish) dissolved in a 'vehicle' or carrier liquid (linseed oil, turpentine, or other solvents, or the synthetic equivalents). Usually there would be drying agents and 'thinners' (solvents) included to make the varnish flow better. A common resin was shellac, a resin secreted by the Lac insect and deposited on plants, shellac is the origin of the term lacquer. Most shellac varnishes use alcohol based solvents.
Distemper, often mentioned in the 1930's and 40's, was a cheap interior paint based on 'whiting', tinted with pigment and mixed with 'size' (a kind of glue). Whiting is simply powdered chalk (calcium carbonate), which is a form of limestone. Distemper was often mixed with water on site by the decorator, usually in a tub resembling a small metal bath. Whiting being a kind of lime had an antiseptic action and whitewash or 'lime-wash' was whiting mixed with water without the colouring. Used for cleaning out cattle wagons in the early days this produced the characteristic white staining on the sides of the wagons.
The motor car industry used large quantities of nitro cellulose pigment, with a resin to give a gloss finish and a plasticiser to make the paint pliable, all dissolved in alcohol. To this is added some form of solvent or thinners made from petroleum or coal tar.
Traffic into a paint works would include drums and bulk tanker loads of wood alcohol (methanol), linseed oil, lactic acid (milk acid, used in 'sizing'), paraffin, turpentine, grain alcohol (ethanol, the stuff that gives booze its kick), chlorine in various forms, benzene, toluene, acids and coal tar pitch.
Also there might be wagon loads of bagged china and other clays, bags of white borax (sodium borate), caustic soda powder, caustic potash, quick lime (a white powder, carried in roofed or sheeted wagons reserved for this traffic), white gypsum dust, white lead, zinc oxide, titanium dioxide (another white pigment), powdered chalk, lamp black (soot) and of course van loads of tins.
XXXX paint works buildings - knightwing factory, loading bank
Note paint works would often be clustered round ports handling
seed crushing, notably at Hull
linseed oil n a yellowish drying oil obtained from flaxseed and used esp in making paint, varnish, printing ink, and linoleum and for conditioning cricket bats . Putty2a a doughlike cement, usu made of whiting and boiled linseed oil, used esp in fastening glass in window sash s and stopping crevices in woodwork whiting n washed and ground chalk used esp as a pigment andin rubber compounding and paper coating
varnish Solution of resins or resinous gums dissolved in linseed oil, turpentine, or other solvents, or the synthetic equivalents. It is used to give a shiny, sealed surface to furniture and interior fittings.
Dyestuffs
Dyes are colourings which dissolve in water, they are used for colouring cloth and yarns, their history goes back more than five thousand years. Thanks to the importance of textile manufacture they have been a significant British industry for many years.
Coventry was renowned in the fifteenth century for its blue woad dye, the expression True Blue, meaning loyal and constant is in fact an old dyers expression, 'true' being the so called 'fast' colours which do not fade.
In the early days of the railways the natural materials used for making dyes were a high value and profitable cargo.
Madders was the root of a European herb which contains the dye Alizarin, ground and boiled up it gave a range of reds. By the 1830's Britain was importing several thousand tons of madder root a year, mainly from France.
A rich vermilion red was produced from sheep's blood (one of the oldest oriental dyes) and unusual reds were made from onion skins, ivy berries, beets and other plants. Safflower provided the red dye for legal and governmental 'red tape'. The discovery of the Americas had brought the bright scarlet dye of the cochineal insect, still used today for food colouring and at least until the 1960's for the scarlet uniforms worn by Guards regiments. Shades of blue were obtained from the Indian Indigo plant and yellows were mainly obtained from Persian Saffron and sumac roots.
By dipping a yarn already dyed yellow into a blue dye shades of green could be obtained, and a rich brown was produced by first using indigo dye then madder dye, but these mixed colours required some skill and a fine sense of timing on the part of the dyer.
Material recovered from animals are also used for dyestuffs, the Phoenicians were based at the far end of the Mediterranean sea but they sailed to Britain to buy copper ores. In exchange they traded cloth dyed purple with a dye obtained from a small shellfish. The molluscs involved yielded only a small amount of the dye so this purple cloth was expensive and was only used by kings and religious leaders. This is the origin of the term 'Imperial Purple'.
In 1856 a chemist called Perkin was trying to synthesize quinine at home when he stumbled across a mauve dye (he had to invent the word Mauve for the colour as nothing like it had been available before). This colour turned out to be based on aniline, which was the basis of the blue dye obtained from the indigo plant. Perkin set up a factory at Harrow in Middlesex and set about researching synthetic dyes in earnest, within ten years there were ten or more synthetic dyes. By the 1960's there were over three thousand synthetic dyes in regular use and the development of synthetic fibres pushed development of new processes.
Not all synthetic dyes came from coal tar - The Backbarrow Ultramarine Works Company in Cumbria produced artificial lapis lazuli blue pigment from a complex mixture of bones, china clay, coal tar pitch, coke, feldspar, hydrated iron oxides, silica, soda ash, sodium sulphate, and sulphur. A related material was 'Dolly Blue' produced by Reckitts of Hull (later Reckitts Coleman), this was added to a wash to make the whites appear whiter (a technique dating back at least as far as the early 17th century, possibly earlier). Up until the 1980s it was common to see small flecks of blue material in washing powders for this purpose and there is still a factory producing synthetic lapis lasuli operating in Hull. The mix was heated in coal fired kilns in a large building, the fumes from this process were rather smelly (and probably fairly toxic) so such a works would require a very tall chimney and the blue powder coated everything in the works, including the staff, so you get to have blue people on the layout.
The development of these synthetic dyes brought an end to a some highly profitable cargo on the railways, Indian indigo growers were ruined almost overnight and whole areas of France which had based their economy on supplying madder root were thrown into economic collapse.
Madders is one of the 'mordant' dyes. Mordants are substances which bind a dye to a textile fibre, they form an insoluble 'lake' in the fibre giving a 'key' to which the dye can adhere, the colour depending upon the metal in the mordant. Important mordants include metallic hydroxides and tannic acid. Tannic acid is a natural acid found in tree bark and some vegetable parts notably nut galls (most is obtained from these using water and alcohol on powdered nut galls). Iron acetate was another of the more important mordants, produced by treating iron filings with yellowish stuff called 'wood vinegar' or more correctly 'pyroliginous acid'. This latter is the liquor produced by wood distillation and contains a range of chemicals. Wood distillation is further discussed below.
There was a certain rivalry between Britain and Germany in the development of dyestuffs and in one vital case chemists in both countries made the same discovery, but the Germans got to the patent office first. The Germans then came to dominate the international dyestuffs industry and held this lead until the First World War. During the war Britain and the United States were forced to develop their own industries and with the end of the war part of the 'reparations' demanded from Germany was the easing of certain patents held by German companies.
At about this time several British chemical companies, including Read Holliday and Levinsteins, grouped to form the British Dyestuffs Corporation. In 1926 this company merged with several others to form ICI (discussed under Chemicals).
XXX Require info on shipping dyestuffs - Does British Dyestuffs Corp still exist as a trading name?
Inks
Most ink factories were small scale affairs so railway connections were not likely but they would generate traffic for a local goods yard. Inks pre-date paper but their development has been a long slow business.
Writing inks are solutions of a colourant in water, usually also containing a small quantity of tannic or gallic acid (made by allowing mould to grow on solutions of tannin or by boiling the latter with acids or caustic soda). Early inks used materials such as soot and the dark purple 'ink' recovered from squid (sepia).
Indian Ink or China Ink dates back a long way and it arrived in Europe in about 1650 in the form of dry sticks. These were made of soot mixed with gum and formed into sticks which are then dried. Soot, also called 'carbon black' or 'lamp black', was shipped in cloth sacks on the railways up to the 1940's and would be associated with a lot of black staining in the loading area.
A Mr. Waterman developed the capillary feed fountain pen in the 1880's but the inks were not of consistent quality, they either clogged or blotted and it was not until the development of Quink Ink in 1931 that a really reliable fountain pen became available.
More specialised inks are required for some printing processes, the Rotogravure system uses resinous colours dissolved in a solvent, the ink dries when the solvent evaporates.
Printing inks are similar to paints in that they use pigments, for letter press and offset lithography these pigments are carried in linseed oil which oxidises in air. Old style newsprint inks used a mineral oil base which doesn't dry as such but is simply absorbed into the paper. Prior to the introduction of modern printing methods in the 1980's one of the duties of a Gentlemen's Gentleman was to iron the newspaper, which soaked the oil deeper into the paper so it did not come off on the chaps hands over breakfast.
The old 'Linotype' printing system used for printing newspapers books and other large runs had individual lead lettering laid up by a large machine and wrapped round the rollers. 'New technology' printing uses a photographic process to produce raised detail on plastic sheets, these are wrapped round rollers for the print run. The inks used for the new print systems are air-drying and do not come off on your hands.
British national newspapers were virtually all printed in London, Manchester or Glasgow up to the late 1980's and up to about 1988 they were then distributed by rail on special services setting off in the very early hours of the morning. Since then road transport, often owned by the same company as the newspaper, has progressively taken over.
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