After printing-on this paste, the goods must be hung up for five or six days in a somewhat damp room. Then after having dipped them in the vat, they are to be steeped in water for half an hour, and slightly washed. Next wince for half an hour, through water at 100° F. containing 2 pounds of soda crystals per 30 gallons. Rinse and dry.
2. Chrome yellow reserve.
Take 1 gallon of water; in which dissolve
3 libs. of nitrate of lead,
1 lib. of binacetate of copper; to the solution, add
1⁄2 lib. of subacetate of lead; and thicken the mixed solution with
3 libs. of gum.
6 libs. of pipe clay. Grind all the ingredients together, and pass through a searce.
After treating the goods as in No. 1., they must be winced for half an hour in a solution containing 5 ounces of bichromate of potash, per piece of calico, and also in a dilute muriatic bath, till the chrome yellow become sufficiently bright.
A chrome orange reserve may be made by introducing a larger proportion of subacetate of lead, and passing the reserve printed goods through weak milk of lime, as already prescribed for producing an orange by chrome.
The basis of the resist pastes used at Manchester is sometimes of more complex composition than the above; since, according to the private information I received from an extensive calico printer, they contain “china clay” (instead of pipe-clay which often contains iron) strong solution of sulphate of copper, oil, tallow, and soap; the whole incorporated by trituration with heat.
In the Lancashire print-works, a little tartaric acid is added to the nitrate of lead, which prevents the colour from taking a dingy cast.
4. Reserves with mordants, or the lazulite style.
1. Black upon a blue ground.