Copper Sulfate – Saline Etch for Aluminum – Test 11: Citric Acid Degeneration Test (Part 4)

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

Room Temperature: 68*F                                                                    Humidity etc: Dry

Experiment Title: Citric Acid Degeneration Test #4

Experiment Goal: We continued using Bath 4 (12 oz spent copper sulfate saline bath, 1 tbsp citric acid) to find a point of etched black for our plates. We were also still trying to deplete our bath. We etched a 6, 9, and 12 minute plate to test their darkness.

Plate material: Aluminum (5052)

Plate Preparation: We etched previously etched plates. So we cleaned the ink from the plates with soy solv II and then degreased with Seventh Generation All Purpose Spray, and backed with contact paper.

Evaluation of Plate Preparation: Normal

Etching Bath Notes: We have been etching in the bath for 57 minutes so far. The bath was getting darker due to the mixing with copper residue.

Time in bath3, 6, 9 minutes (all pates previously etched for 3 minutes)

After Bath Evaluation: There was little going on in the bath. It was much much weaker compared to weeks before. The was little activity visible when etching.

Removal of Grounds: N/A

Inking Methods: Bone black oil-based etching ink, 10% 00 burnt plate oil (Nick inked these plates to keep wiping methods consistent)

Paper Type: Hahnemuhle Copperplate

Soaking Time: 1 Hour

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

Conclusions: We did not etch to complete black. Our 6-minute print looked very similar to our 3-minute prints. And our 12-minute plate was definitely darker, but still gray not black. Our 9-minute plate made a nice mid tone between our 6 and 12-minute prints. Bath 4 is much weaker than it was two weeks ago when we started etching in it.

6, 9 and 12-minute etch comparisons.

Wearing down 4th 12 oz sample bath with aluminum strips. Also pictured is the oxidized copper sludge.

Size comparison of aluminum strip to copper residue build up in bath.

Bottom view of 4th 12 oz sample bath that was used to etch. Citric interrupted/halted the oxidation process of the copper.

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