Copper Sulfate – Saline Etch for Aluminum – Test 10: Citric Acid Degeneration Test (Part 3)

Name: Nick Osetek & Tessa Chambers                                                 Date: 4/26/2018

Room Temperature: 68*F                                                                    Humidity etc: Dry

Experiment Title: Citric Acid Degeneration Test #3

Experiment Goal: We continued using Bath #4 (12 oz spent copper sulfate saline bath, 1 tbsp citric acid) until depletion. We cut another six plates (plates 13-18) to etch until this bath depletes.

Plate material: Aluminum (5052)

Plate Preparation: Buffed with fine grit steel wool, degreased with Bon Ami and soy sauce, backed with contact paper

Evaluation of Plate Preparation: Normal

Etching Bath Notes: We have been etching in the bath for 39 minutes so far. The copper seems to have settled to the bottom. The grayish tone from the week before seems to have changed back to clear blue due to the copper settling. The pH was stable between 2.8 and 3 when etching.

Time in bath: 18 minutes total in 3 minute increments

After Bath Evaluation: More copper residue built up from etching, which started to mix into the bath. The colour started turning grayish again.

Removal of Grounds: N/A

Inking Methods: Bone black oil based etching ink, 10% 00 burnt plate oil (Tessa wiped, Nick polished)

Paper Type: Hahnemuhle Copperplate

Soaking Time: 30 minutes

Press, blanket set up, pressure: Praga, 2 blankets, 1/9-left 1/9-right

Conclusions: Our tones were pretty consistent with our previous lighter outcome from citric acid test #2. There were some strange patchy areas of darkness and lightness that we’re not sure of where they’re be coming from.  Bath seems to still be degenerating.

After immense help from Dr. Richard Peltier and our continued journey with our baths, we had a few follow up questions that needed some clarification.

Here are our questions, followed by Dr. Peltier’s answers:

Follow Up Questions April 26, 2018

Bath comparisons after main bath settled and citric had more time to regenerate baths.

3-minute plate comparisons. Plates 13-18.

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