A bowl, about 6 cm. across the top, is kept for each colour, and also a hog's-hair brush and a birch-twig brush.
A small bundle of birch twigs is tied round with thread, leaving about 4 cm. of the twigs free, the thickness of the lowest part tied not exceeding 1 cm. The bristles of the brush are tied back so as to form loops and held awhile in boiling water so that they retain their shape after drying and untying. With a brush made up in this way, drops may be laid on anywhere.
For all drawn-out edges only bristle brushes are used, whilst for all other edges a brush is used only for laying on the first colour. For some edges a wide brush is used, so that the whole trough can be filled at one blow; a carpet brush with a short handle is most convenient to use.
A little stick for tracing the colours is also necessary—a butcher's skewer is as good as anything. Besides this, the colours are drawn by combs of various widths; these are easily made by glueing pins with their heads at fixed distances between two strips of mill-board: the result is a tool resembling a comb. All requisites can be conveniently kept in a little wooden box together with the colours. Nowadays only Halfer's ready-made colours are used.
Any one wishing to learn the process of marbling edges would be wise not to attempt all the styles at once, but should be content to learn one before proceeding to another. We will commence with "comb" marbling, also known as "feather" marbling.
When marbling is to be done, the colours must always be tested first. A little colour is shaken into each bowl and its brush placed with it, and one or two drops of prepared oxgall added to each colour so as to make the colour float on the surface.
One prepares one's own oxgall. An ox gall in the gallbladder is procured from a butcher, a glass funnel is placed in a bottle which has been weighed beforehand, and the bottom of the gall bladder is pierced so that the bladder empties its contents into the bottle. After finding the weight of the gall, add to the weight of the gall alone one-sixth and pour into it spirit of wine until the weight is equalized; shake thoroughly and strain the mixture, which will now be quite clear and ready for use.
The colours, with their brushes, are placed in the order in which they are to be used, beginning with the darkest and finishing with the lightest.