Page:The Art of Bookbinding, Zaehnsdorf, 1890.djvu/100

70 Prussian blue, indigo, some green, flake white, and lamp black. The brushes for the various colours should be of moderate size, and each pot of colour must have its own brash. Small stone jars are convenient for the colours, and a slab of marble and muller to grind them must be provided. The combs may be made with pieces of brass wire about two inches long, inserted into a piece of wood; several of these will be required with the teeth at different distances, according to the width of the pattern required to be produced. Several different sized burnishers, flat and round, will be required for giving a gloss to the work.

The first process in marbling is the preparation of the size on which the colours are to be floated. This is a solution of gum tragacanth, or as it is commonly called, gum dragon. If the gum is placed over night in the quantity of water necessary it will generally be found dissolved by the morning. The quantity of gum necessary to give proper consistency to the size is simply to be learned by experience, and cannot be described; and the solution must always be filtered through muslin or a linen cloth before use.

The colours must be ground on the marble slab with a little water, as fine as possible; move the colour from time to time into the centre of the marble with a palette knife, and as the water evaporates add a little more. About one oz. of colour will suffice to grind at once, and it will take about two hours to do it properly. Having everything at hand and ready, with the size in