Vaughn, Samuel Jesse, b. 1877 · Bloomington, Ill. : Public school pub. co. · leaf 65
ay. If largesurfaces are to be etched, quite a large quantity of acid isdesirable, or else a changing or strengthening of the solu-tion during the process. As soon as the acid becomes some-what burdened with the metal, it ceases to act at all freely,and even begins to deposit a blue nitrate upon… … FIG. 29. WOOD CUTS AND METAL PLATES 55 and lets the acid under to play havoc with the design. Xu-nierous bubbles and yellow-green fumes indicate that theacid should be weakened by the addition of a small quan-tity of water. By observing the progress of the etching occasionally,it can be told when…
Printing · Bookbinding
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