Then wash the dyed fabric and notice whether the dyestuff washes off or not.
Which sample has absorbed the greatest amount of dyestuff from the liquid?
Then wash the dyed silk and notice whether the dyestuff washes off or not.
If the dyestuff has penetrated into the interior of the thread, it is not printed.
Under the deep-furrowed, brown surface bark is a yellow layer, rich in tannin, and a dyestuff called quercitron.
This dyestuff is largely used by calico printers and other dyeing manufacturers.
The dyestuff for black was a sediment or deposit of an intense black found at the bottom of pools in bogs.
The high price of this dyestuff causes its employment to be somewhat limited.
Since a fair amount of caustic soda is necessary for the setting of the vat, the dyestuff is not suitable for animal fibres.
The boxes may contain the same or different liquors, according to the nature of the dyestuff employed.