	Etching Copper Plates Ruth Pittenger
Student Projects, Print Making

Introduction

We experimented with etching zinc plates in two labs. While zinc plates work well for introducing the process of etching metal plates, many printmakers find that zinc plates are too easily worn down after repeated prints are made. Copper plates are more durable and yield more accurate prints even after repeated printing from the same plate.

Background

I experiemented with etching copper plates with three different etchants: 3M nitric acid, 6M nitric acid, and Ferric chloride. Each etchant was in contact with a copper plate for intervals of 5, 10, 15, 20, 25, 30, and 25 minutes. I then made prints from each plate to determine which etchant produced the best print. I also took into consideration the level of control the experimenter had over the speed and quality of each etchant during the process.

Procedure

Preparing the Plate:

1. File edges of each copper plate

2. Apply Putz pomade to the plate using a paper towel in order to remove oxide coating from plate

3. Clean copper plate using mineral spirits

4. Remove residue of mineral spirits and any fingerprints from plate using isopropyl alcohol

Coating the Plate:

1. Apply thin, even coating of waxy acid-resistant etching ground to both sides of the copper plate and allow to dry

2. Touch up any missed areas on the plate using stop-out varnish

Designing the Plate:

1. Using a sharp metal etching tool, remove acid-resistant ground from plate to expose copper metal where etching is desired

Etching the plate:

Etching copper plates in (left): ferric chloride, and (right): 6M nitric acid

1. Immerse one coated copper plate in 200 mL of a) 3M nitric acid, b) 6M nitric acid, or c) Ferric chloride*

* Copper plates etched in ferric chloride must be placed face-down in the etchant bath. Any bubbles which form in either concentration of nitric acid must be removed from copper plate using a clean paintbrush.

2. Remove plate from acid bath at intervals of 5, 10, 15, 20, 25, 30, and 35 minutes rinsing plate with water each time and record observations

3. Remove acid-resistant ground from plate at five minute intervals

4. After total of 35 minutes contact time in the acid bath, remove copper plate, rinse with water, and remove the ground from the plate using first mineral spirits and then isopropyl alcohol

Inking the Plate and Printing:

1. Apply black oil-based ink to each plate, making sure ink gets into the etched areas of the plate

2. Remove excess ink from plate using a satin cloth

3. Using a rolling press, print from plate directly onto damp paper and allow to dry

Prints from copper plates etched in 6M nitric acid (left), and ferric chloride (right), for 60 minutes each

Observations and Data

Etching the Copper Plates:

	3M nitric	6M nitric	Ferric chloride
5 min.	a few bubbles appear	many small bubbles form	no bubbling
10	all bubbling stops	speed and depth of etching quickly becomes difficult to control	some etching detectable to eye and to touch
15	virtually no etching detectable to the eye or to the touch	bubbling slows somewhat	etching is easier to control
20	"	deeper etching continues	lines etched clearly follow design drawn in ground with etching tool
25	"	"	etching continues slowly
30	"	"	"
35	"	etching detectable to both eye and to touch	"

Prints:

For example, here is a table with two rows and three columns. 80% of width of screen. Border = 1 unit. Dreamweaver does some strange things with heights of rows and widths of columns. You can always click on the border between two rows or between two columns (the cursor turns into two parallel lines with arrows pointing perpendicular to the lines) and move the border to where you want it to be. See Bordley if you have questions

Conclusions

Ferric chloride proved to be the most suitable etchant for etching and printing from copper plates. The ferric chloride allowed the experimenter the greatest amount of control over the etching and printmaking processes. Prints made from the copper plates etched with ferric chloride were closest to the original desired design.