Colours with Loywood. 373 



The quantity of bran to be added depends upon the 

 weakness or strength of the mordant. In the first case, 

 the quantity of bran should be equal to the weight of the 

 calico ; in the latter case, more is required. 



Bran for cleansing dyed stuffs. — Bran is employed to 

 cleanse white grounds, especially such as are dyed with 

 madder. It removes the colours which have run into the 

 unprinted parts, and imparts to the madder-red a clearer 

 lustre. 



The bran-bath can, with madder colours, be brought to 

 the boiling point, but must not long remain there, otherwise 

 the colours will be weakened. 



Soap may be added to the bran-bath, especially where there 

 is much red, and less of white ground. 



Upon white grounds dyed with quercitron, bran acts to 

 great advantage ; only the yellow colours will be injured if 

 the bath is too hot. The temperature should never rise 

 above 189° F. 



In all these cases portions of the bran combine with the 

 calico, and the colours upon it. In consequence, the co- 

 lours become brighter, and the calico acquires stiffness 

 after careful washing. 



Bran as an addition to the dyeiny solution. — Logwood 

 colours appear brighter when a determinate quantity of 

 bran is added to the solution, and the dyeing performed. 

 This is particularly important in pieces upon which the 

 alum or copper mordants have been printed. 



COLOURS WITH LOGWOOD AND ALUM MORDANT, NO. I. 



When 12 lbs. cotton are dyed with lib. logwood and 3 lbs. 

 bran, the colour produced is a fine violet blue ; without 

 the bran, the colour is brown. 



The wood and bran are first boiled together with little 

 water, by which the solution acquires a bright-red colour; 

 it is then cooled by the addition of more water, and the 

 previously well-moistened cloth introduced. 



The dyeing is performed at a heat which ascends to boil- 

 ing. After the dyeing, the solution to which bran was 

 added possesses a yellow colour. It still contains a suffi- 

 cient quantity of logwood to dye 3 lbs. of cloth violet blue. 



