Ocean Acidity and Copper Etching

Last week I had the pleasure of joining Senior Research Scientist, Steve Archer to Ocean Point just five minutes from the laboratory. We were looking for coralline algae that had washed ashore and deposited their white segmented calcium carbonate “skeletons.”

Throughout our discussions we noticed an interesting intersection between my work with printmaking (specifically the etching of copper with ferric chloride) and Steve’s recent work with ocean acidification. After looking at some SEM (Scanning Electron Microscope) images of the effects of rising ocean acidity levels on small crustaceans, snails and other calcium carbonate depositing life forms, I wondered what types of chance patterns the acidic ocean water would produce on left behind shells or “skeletons” (I’m using this in quotations because I am not entirely sure it’s an accurate word to describe the structures left behind by coralline algae).

I have recently been exposing copper plates to an acid solution that printmakers call the Edinburgh Etch (essentially ferric chloride, water and citric acid) for several days to achieve what is traditionally an undesired/over-etched plate. Instead of allowing a precisely timed and measured etch to take place, I leave the removing of the plate to happenstance…often times forgetting I put the plate in for several days. The results are typically heavily degraded plates that have been etched through in certain areas, while producing a variety of textures, patterns and lines where ink can be “expressively” wiped (by this I simply mean they are incredibly difficult to edition. Each inking/print is very different). The plates that I produced had some interesting relationships to some of the SEM images of these ocean etched shells that I mentioned previously. Thus, we had the idea of etching several different calcium carbonate structures in the same manner that I had previously etched copper with (using some different acids), and subsequently using different microscopy processes to photograph the surfaces of these structures. In turn these images will hopefully provide raw material/inspiration to start manipulating with digital and analog print processes.

Note: The implications of rising ocean acidity on the growth and development of calcium carbonate/shell bearing oceanic life forms are becoming better understood as more studies are conducted. What I have gathered is that these protective calcium carbonate structures have a more difficult time developing and under projected acidity levels and may be degraded/compromised over time. Heres an article with several SEM images that puts this in more scientific yet understandable terms…Ocean Acidity & Pteropods

Ocean Acidity and Copper Etching