Copper Sulfate – Saline Etch for Aluminum – Test 4: Aquatint Step Test (Part 2)

Name: Tessa Chambers & Nick Osetek                                  Date: 3/15/2018

Room Temperature: 70*F                      Humidity, etc: Dry

Experiment Goal: To become familiar with etch times in the copper sulphate saline bath to create aquatint shades (10 second increments up to 50 seconds.)

Plate Material: Aluminum (5052)

Plate Preparation (surface prep, ground application, image making process, etc): The plate was beveled, degreased with Bon Ami, then the plate was backed, and small 0-50 second sections were drawn in on the plate to monitor etch times for each section.

Evaluation of Plate Preparation: Aluminum plate took much more time to degrease compared to copper.

Etching Bath notes: 140g copper sulphate, 140g salt, 2 liters of warm water. This was the fourth use of the bath.

Time in Bath: 10 second intervals until 50 seconds.

After Bath Evaluation: Bath was cloudier, and build up of copper residue was floating around in the bath, bath was still visibly turning slightly greener. At this point we’ve come to the conclusion the colour of the bath is an important factor in determining the bath’s strength. Deep clear blue is a strong bath, as you etch in the bath the red copper residue (copper oxide) degrades and turns into elemental copper which is a minty green sludge built up on the bottom.

Removal of Grounds (chemicals used and evaluation of effectiveness): No grounds were applied.

Inking Methods: Hanco Bone Black oil based etching Ink, 10% Burnt Plate Oil 00, wipe plate normally

Paper Type: Hahnemuhle Copperplate

Soaking Time: 15-20 minutes

Press, blanket set up and pressure: Praga press, 2 blankets, Right setting: 4/9  Left setting:5/9

Conclusion: We found the second interval test more successful than the minute interval test. The tonal range was much more fluid, compared to the minute test which became incredibly dark only after 3 minutes.

2nd print of 1-6 minute (right) and 0-50 sec (left) plates

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