Name: Isabella Lores-Chavez
Date and Time: 2016.09.14, 11:00 am
Location: Hamilton Heights, Manhattan
Subject: Growing verdigris
To make verdigris, I followed the recipe based on Mappae Clavicula, compiled on the blog vastrepast.net:
"Take a new pot and put sheet of the purest copper in it; then fill the pot with very strong vinegar, cover it, and seal it. Put the pot in some warm place, or in the earth, and leave it there for six months. Then uncover the pot and put what you find in it on a wooden board and leave it to dry in the sun."
Materials - provided by Making & Knowing Lab
1 copper sheet
1 glass mason jar with lid
1 short length of twine
I used apple cider vinegar with the mother in it, from my pantry:
Although I primarily followed the instructions of the above recipe, I compared the recommendations for making verdigris from other recipes listed on the blog, as well as the recipes in Mary Merrifield's Original Treatises Dating from the XIIth to XVIIIth Centuries on the Art of Painting (London: John Murray, 1849). Consulting these led me to believe that I ought to pour a vinegar into the mason jar to fill about a third of it, leaving plenty of room in the mason jar to hang the copper sheet without having it touch the vinegar. To hang the copper sheet, I simply folded one edge of the sheet over the piece of twine, leaving enough twine on either side of the sheet to drape onto the rim of the mason jar. To hold the twine in place, I simply used the lid, closed tightly.
I set my mason jar with the copper sheet and vinegar in it on the windowsill of one of the windows in my bedroom (on the fourth floor of an apartment building). The window faces south onto 150th Street, receiving direct sunlight during much of the day. I thought this would make for ideal verdigris growing conditions, as the spot on the windowsill would be consistently warmed during the day just by the direct sunlight. After 24 hours, the copper sheet had already begun to appear green.
I removed the mason jar from the windowsill on the morning of October 3rd at around 9:15 am. I removed the lid from the mason jar, making sure to hold the twine on the rim of the jar to keep the copper sheet from dipping into the vinegar. Then, being very careful not to touch the copper with verdigris growing on it, I lifted the copper and twine out of the jar and deposited it in a Ziploc bag, to be transported to the lab for painting out.
Verdigris Painting Out
Name: Isabella Lores-Chavez
Date and Time: 2016.10.03, 11:00 am
Location: Columbia University, Making & Knowing Lab
Subject: Verdigris - scraping and painting out
On October 3rd in the lab, we first scraped the verdigris from our copper sheets. To do this, I put on gloves, took my copper sheet from the Ziploc bag, and set it on a ceramic plate. Holding the copper sheet as much as possible by the twine with one hand, I used a metal scraping tool to remove as much of the green patina from the sheet as possible. At first, I scraped lightly across the surface, watching verdigris particles falling onto the ceramic plate like a delicate green dust. The copper sheet remained green, however.
After several minutes scraping, I realized I could dig into the copper sheet much more, to remove the verdigris particles in earnest. With more force behind my scraping motions, I could actually reveal the copper sheet underneath the patina, which allowed me to get an even greater abundance of verdigris particles on my ceramic plate.
Once I had scraped enough to get a sizable mound of pigment, and enough that I felt like my copper sheet was mostly free of large swatches of verdigris, I moved on to the painting out process. First, I set up a station where I could mix my pigment with two different kinds of oil: linseed oil and walnut oil. I divided my mound of pigment into two equal portions, to mix in with each kind of oil. I mixed the verdigris with linseed oil first, using the metal spatula instrument to mix the two together, mostly achieved by pressing the mixture on the spatula against the plate. Then I used a glass muller to make sure the pigment was being ground into the linseed oil; the mixture felt relatively slippery and not grainy once both drops of linseed oil had been added. I used a total of two drops of linseed oil, administered using a plastic pipette. I ended up with a green oil paint that had a consistency a little thicker and more viscous than the oil, but still loose enough to be applied easily to a brush and subsequently to a surface for painting.
When I mixed the walnut oil with the verdigris pigment, I found that I needed slightly more oil: I used three drops total of walnut oil, also administered with a pipette. This may just have been the result of an imprecise division of my supply of pigment. Three drops were absolutely necessary because at two drops, the mixture was thick and globby, and the pigment did not seem sufficiently ground and mixed into the oil. As with the linseed oil, I mixed the pigment and walnut oil with a metal spatula and a muller, using the spatula to scrape the mixture from the bottom of the muller to put back onto the ceramic plate for further mixing.
My walnut oil paint appeared to be a darker green, and more opaque, than my linseed oil paint. Using a small paintbrush, I applied each kind of green paint to one prepped square on the painting boards available in the lab. I was struck by how turquoise the paint looked once I had actually painted it out. After applying the paint, I also noticed a good amount of uniformity to the paint, which indicated to me that the pigment had been sufficiently ground and mixed into the oil. The paint surface had a shiny quality to it, and was not so opaque that I couldn't see the white ground when I first applied it. I use all of the oil paint I had made for each square, covering the white ground completely and enough to make the turquoise relatively opaque.
As I walked away from both painted squares that afternoon, I felt distinctly perplexed by the notion that the color would change and become greener with time. It absolutely made me wonder how the painters I love, whose work and especially vivid colors I admire, approached executing their compositions, considering that the initial tone of the green paint made with verdigris would not last and would change into a different green.
Date and Time: 2016.10.10, 2:00 pm
Location: Columbia University, Making & Knowing Lab
Subject: Squares painted with verdigris, one week later
One week later, both painted squares are distinctly greener! The overall tone of the paint still seems rather turquoise to me, but I know it will continue changing.
Date and Time: 2016.10.17, 2:00 pm
Location: Columbia University, Making & Knowing Lab
Subject: Squares painted with verdigris, two weeks later
This week, the painted squares seem much greener to me. I would call this color green, more so than turquoise.
Date and Time: 2016.10.24, 2:00 pm
Location: Columbia University, Making & Knowing Lab
Subject: Squares painted with verdigris, three weeks later
The verdigris of the painted squares has continued to become greener.
