Etching Table

The Etch table below is for your convenience and should be modified for your situation. The stone table is based on full strength nitric acid measured by drops to an ounce of gum arabic. For plates, the references are to a full strengeth mix of gum arabic and phosphoric acid to a pH of 2.1-1.7 or T.A.P.E.M. For your convenience the approximate pH is also noted.

Stone

 Light/Delicate

 Medium

 Dark/Heavy

 Plain Gum

 6-10 drops/oz.

 10-15 drops/oz.

 4-4.5 pH

 3.0-2.5 pH

 2.5-1.7 pH

Plate

 Light/Delicate

 Medium

 Dark/Heavy

 50/50

 50/50

 Straight Etch

approx 3.0 pH

approx 3.0 pH

approx 2.1-1.7 pH

 

Adjustments should be made for type of stone, drawing style, and use of materials.

When etching paste tusche on stone, do not leave the etch on too long as it may cause
the wash to lift off.