This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
(1) Mix powdered ochre, Venetian red, and umber, in size, in proportions to suit; or a richer stain may be made with raw sienna, burnt sienna, and Vandyke. A light yellow stain of raw sienna alone is very effective.
Lay on liquid ammonia with a rag or brush. The colour deepens immediately, and does not fade; this being an artificial production of the process which is induced naturally by age. Potash bichromate, dissolved in cold water and applied in a like manner, will produce a very similar result.
(3) In Germany, the cabinet-makers use very strong coffee for darkening oak. To make it very dark: iron filings with a little sulphuric acid and water, put on with a sponge, and allowed to dry between each application until the right hue is reached.
(4) Whitewash with fresh lime, and when dry brush off the lime with a hard brush, and dress well with linseed-oil. It should be done after the wood has been worked, and it will make not only the wood, but the carving or moulding, look old also.
(7) A good method of producing the peculiar olive brown of old oak is by fumigation with liquid ammonia; the method has many advantages beyond the expense of making a case or room air-tight and the price of the ammonia. It does not raise the grain, the work keeping as smooth as at first. Any tint, or rather, depth of the colour can be given with certainty; and the darker shade of colour will be found to have penetrated to the depth of a veneer, and much farther where the end grain is exposed, thus doing away with the chance of an accidental knock showing the white wood. The colouring is very even and pure, not destroying the transparency of the wood. It is advisable to make the furniture from one kind of stuff, not to mix English oak with Riga, and so on. They both take the colour well, but there is a kind of American red oak that does not answer well. In all cases care must be taken to have no glue or grease on the work, which would cause white spots to be left. The deal portions of the work are not affected in the least, neither does it affect the sap of oak. The best kind of polish for furniture treated in this manner is wax polish, or the kind known as egg-shell polish. The process of fumigation is very simple.
Get a large packing-case, or better still, make a room in a corner of the polishing shop about 9 ft. long, 6 ft. high, and 3 ft. 6 in. wide; pass paper over the joints; let the door close on to a strip of indiarubber tubing; put a pane of glass in the side of box or house to enable you to examine the progress of colouring. In putting in your work see that it does not touch anything to hinder the free course of the fumes. Put 2 or 3 dishes on the floor to hold the ammonia; about 1/2 pint is sufficient for a case this size. The ammonia differs in purity, some leaving more residue than other. Small articles can bo done by simply covering them with a cloth, having a little spirits in a pot underneath. A good useful colour can be given by leaving the things exposed to the fumes overnight. The colour lightens on being polished, owing to the transparency thus given to the wood.