"This is a little more difficult as I have not been able to discover a precise recipe for the pigment. Franklin indicates that it contain Zinc Oxide but this is from the 1850s. Zinc Oxide was not available in quantity until the 1840s. The paint contained Lead Oxide and some lamp black. This gave light grey to medium grey colour. Remember White Lead on exposure to hydrogen sulphide formed lead sulphide which is black. So the longer exposed to the gasses from gunpowder deflagration, the darker the shade. Hence great differences from old to new paint. Some illustrations indicate almost dark grey in appearance."
This is something I am particularly interested in at the moment in trying to paint some new 28mm models.
Having always used since the '70s a very dark grey, the old Humbrol 'British Equipment Grey', I was having second thoughts this time as all I see these days are pictures of very light grey equipment both in books or used on models.
However when I looked at Spellmount - "British Napoleonic Field Artillery" which has a small but informative section on this very subject he refers specifically to the same Humbrol colour I have used in the past.
In essence what I think he says, take the recipe for the later 'Zinc Oxide' version which is known and just substitute 'White Lead' for the 'Zinc Oxide', the resulting paint was then matched to the Humbrol colour.
This colour though is in no way close to the light grey which seems to be prevalent today, to be honest I wouldn't even really call it 'medium' and this is before any darkening through age/use but I would love to hear your views on what Spellmount says.
Below is the section from Spellmount:
Colour of Artillery Equipment
There is some dispute between different authorities regarding the colour of artillery equipment. The contemporary paintings show a dark grey colour, but modern artists seem to prefer a blue-grey. As far as can be determined during the Napoleonic period all wood and iron work of artillery equipment was painted to protect it and the brass gunes were polished when circumstances warranted but were usually left dull on campaign(45).
There are several indicators that the carriages were painted; Dickson recorded in December 1809 that his brigade had been sent to Quinta Nova for just that purpose(46). The facilities in the Royal Carriage department included 'painters stores and sheds for the painting of carriages' and there are several references to the cost of paint colours and and oil(47). One reference in 1812 specifically refers to gun carriages painted in a 'lead colour'(48). One of the few paintings to show such equipment is David Morier's 'Royal Artillery in the Low Countries'; this shows a darkish grey, which matches the description 'lead' (49).
According to later records of 1858 when white zinc oxide had replaced white lead, all wood was painted a grey, called 'lead', later 'white lead':
The principal ingredient, used in making paint in this Department, is the oxide of zinc. The raw oxide is mixed with raw linseed oil, in the proportion of two gallons of oil to one cwt. of oxide, it is then incorporated in a pug mill, and afterwards passed between stone rollers until it acquires a uniform consistency; in this state it is termed 'ground white zinc', and is stored in kegs until required for use. the proportions of the ingredients for making the several kinds of paint used in the service are as follows:
For Carriages, &c. for Home Service
Ground oxide, of white zinc 112lb
Oil (bolied), for grinding 3 quarts
Manganese, as a drier 8 ounces
Raw linseed oil, for mixing 2.5 gallons
Bold linseed oil, to give body and gloss 2.5 gallons
Turpentine, for thinning and drying 2.5 gallons
The above ingredients are carefully incorporated and strained through a wire sieve to make 197lb.
For tropical climates, where a lighter colour is required, the lampblack is reduced to 1lb mixed with one pint of boiled oil.
Black Paint, for Iron Work
Boiled oil, for grounding 8 gallons
Boiled oil, for mixing 4.5 gallons
Turpentine 1 quart
Red lead for drying 2lb
Litharge for drying 4lb
The above ingredients are carefully incorporated and strained through a wire sieve to make 164lb(50).
There is no evidence to support the use of any other colourant and while ironwork was painted black the metal ends of the shafts, the elevating mechanisms, trunnion bearing, inside of the capsquares, axletree arms, linchpins and the washers were not painted but 'kept bright' and lightly oiled. Tests conducted with the relevant pigments and oils give tow quite different tones of grey.
The re-enactor or modeller should note when lead white is mixed to the above recipe it produced a colour very similar to Dulux, Ebony Mist 3. The zinc white, used after the period, produced a darker grey similar to Dulux Ebony Mist 2. Analysis of the sample of the earlier paint using white lead was sent to the NCS Colour Center and provide NCS reading of 'S 6000-N'. NCS Colours can be obtained at a variety of outlets including Dulux, crown, Johnston and Leyland. A similar analysis was carried out by DG Colour using the 'Munsell' system and Humbrol Modelers Paints. The modeller will find their nearest equivalent is Matt Ocean Grey 106, which is equivalent to Revel 47.
In 1861, the colour of British artillery equipment was changed to green, to make the equipment less conspicuous, but this was abandoned in December 1862, and the colour reverted to the original lead colour.
45 Mercer, 1807 p333
46 Dickson, 1908 pp.126,130,142,145
47 Hogg, 1963 pp485,527
48 Henry, 2003 p16
49 Morier, D. Royal Arillery in the Low Coutries Rotal Collection cat#125
50 HMSP, 1858 p11