MORDANTS.
287
and becomes re-dissolved on cooling, especially if well stirred until quite cold.It should not be used hot. When it is required to dilute the mordant withmuch water, as for instance for light rose-colours, it is best to thicken thewater first by means of starch, and to add next the mordant to that mixturewhen nearly cold. The following are prescriptions of thickened mordants forred and rose-colours, ready made up for printing with the cylinder-machine.*
Deep Red. Medium Red. Bright Red.
Acetate of alumina at 9° Baume ]
[■ 1 litre
1 litre
i litre
= 1-067 sp. gr. = 13 0 Tw. .. 1Water.
1
I „
4 litres
15 litres
Starch.
240 grms.
0
0
Roasted starch .
60 „
2 kilos.
6 kilos.
Gallipoli oil (huile tournante) ..
30 ..
Decoftion of Lima-wood ..
164 „
Red Mordant for Madder.
Garancin mordant at ii° Baume . 1 litre
White starch.no grms.
White-coloured roasted starch (British gum).75 ,,
Bright Red.
Strong mordant at xi° Baume (see above) . 1 litre
Acetic acidf at 2 0 B. == 1*007 sp. gr. — i$° Tw. 4 litres
Solution of British gum containing 750 grms. to the litre g ,,Pipe-clay water containing 1 kilo, of pipe-clay to the litre 5 ,,
Red Mordant for Deep Red.
(For fine designs).
Acetate of alumina at 9 0 B.
Water.
Brazil-wood decoftion .
Acetic acid (as above) ..
Alum .
Pyrolignite of lead (crude acetate).
White starch .
Gallipoli oil (huile tournante) .
Solution of nitrate of copper at 52 0 B. = 1*547 S P* g r *
= iog|° Tw.
i*o litre6*o litresio*o „
5'° »
2*5 kilos.2'5 „
3*o »
375 grms.
375 »
Note that the sulphate of lead which is formed remains in the mixture,serving the purpose of giving body, and thereby aiding the regularity of theexecution of the fine designs.
* See D. Kcechlin-Schouch, Sur le Mordant Roug.e, “ Bulletin de la Societe Industrielle deMulhouse,” vol, i., p. 277. m
t It should be borne in mind that the specific gravity of vinegar and of acetic acid is noproper test for their goodness ; acetic acid is specifically lighter than water; vinegar, accordingto its origin, contains a variety of other substances in solution along with acetic acid and water.The quantity of acetic present in vinegar varies from 2 to 8 per cent.