irectly to the material: and adjective, which includes the greater num

the first is mordanting and the second is the colouring or actual dyeing

a mordant as "the body, whatever it may be, which is fixed on the fibre in combination with any given colouring matter." The mordant is first precipitated on to the fibre and combines with the colouring matter in the subsequent dye bath. But, whether the

her places where primitive dyeing methods are still carried on. Alum has been known for centuries in Euro

s only superficial, the dye will be uneven: it will fade and will not be as brilliant as it should be. The brilliancy and fastness of Eastern dyes are probably due to a g

e; with tin, scarlet; and with chrome or copper, purple. Logwood, also, if mordanted with alum, gives a mauve colour; if mordanted with chrome, it gives a blue

more difficult to dye than wool or silk. Their fibre is not so porous and will not hold the dye stuff without a more complicated preparation. The usual method of preparing linen or cotton is to boil it first with some astringent. The use of astringents in dyeing depends upon the tannic acid they contain. In combination with or

L

ar should be added to the alum bath as it helps to brighten the ultimate colour. The usual amount of alum is a quarter of a pound to a pound of wool. As a rule, less mordant is ne

e wool is entered. Raise to boiling point and boil for one hour. The bath is then taken off the fire and allowed to cool over night. The wool is t

R

ate, copperas,

e colouring matter and then add the mordant to the same bath in a proportion of 5 to 8 per cent of the weight of the wool, and continue boiling for half an hour or so longer. With some dyes a separate bath is needed, such as with Camwood or Catechu. Great care is needed in the using of copperas, as, unless it is thoroughly dis

t in a decoction of the dye for about 1 hour, and then for 1/2 an hour with the addition of 5 to 8 per cent of copperas.

I

tin crystals, tin sa

arer and faster colours than the other mordants. When used as a mordant before dyeing, the wool is entered into the cold mordant bath, containing 4 per cent of stannous chloride and 2 per cent oxalic acid; the temperature is gradually

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romate. Bichrom

d for 1 to 1-1/2 hours with bichromate of potash in the proportion of 2 to 4 per cent of the wool. It is then washed well and immediately dyed. Wool mordanted with chrome should not be exposed to light, but should be kept well covered with the liquid while being mordanted, else it is liable

PP

gris, Blue Vitriol, Blu

, and the mordant applied afterwards to fix the colour. With cream of tartar it is used sometimes as an ordinar