Copper Sulfate – Saline Etch for Aluminum – Test 24: Depleted Bath Revival #3

Name: Nick Osetek & Tessa Chambers                                                 Date: 6/19/2018

Room Temperature: 75*F                                                                    Humidity etc: Dry

Experiment Title: Depleted Bath Revival #3

Experiment Goal: To once again kill and revive our 5-gallon bath by adding 762g of copper sulfate & salt.

Plate material: Aluminum 5052

Plate Preparation: Degreased with Bon Ami and soy sauce

Evaluation of Plate Preparation: Normal (not steel wooled or backed bc small size of test strip)

Etching Bath Notes: Before Revival: Bath was clear with a large build-up of copper sediment built up at the bottom. Before revival we removed some of that copper sludge from the bath.

After Revival: After the revival with 762 g of copper sulfate and salt the bath turned very dark mossy green. We think the bath was this dark due to the green color of the bath mixing with the large amount of copper residue.

Time in bath5 min (2x) for each test strip

After Bath Evaluation: The bath was still cloudy mossy green.

Removal of Grounds: N/A

Inking Methods: Bone black, 10% Burnt Plate Oil 00

Paper Type: Hahnemuhle Copperplate

Soaking Time: 1 hour

Press, blanket set up, pressure: Praga press, 2 catchers, 1/8, 1/8

Conclusions: Dead Bath: Our test strip before revival was consistently light with our past dead bath test strips. The strip barely etched.

Revived Bath: Our revived 5-minute test strip was consistently dark with our past 5-minute revival test strips. We again successfully revived our bath.

Before killing bath for the 3rd time.

Sodium chloride measured out to revive bath. Note clear mordant in the background.

Copper sulfate measured out during bath revival. Note the red copper sludge in the mordant that was never oxidized due to the worn out bath.

Revived bath after adding copper sulfate and sodium chloride. Dark, murky green in color.

Removing excess copper sediment from the etch bath. Yellow chemical reaction caused by mixing active copper compounds with neutralized (soda ash) sludge.

Resulting prints from before/after reviving bath for the 3rd time. Smilies faces were blocked out using a sharpie paint pen, which is an effective stop out tool for aluminum.

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