Table of Contents

[Verdigris]

Name: Celine Camps

Date and Time:

2018.09.10, 5:00 pm

Location: Private apartment, 405 West 118th Street.

Subject: Selecting a ‘making verdigris’ recipe

Assignment
Grow your own verdigris

Objective
Become familiar with reconstructing early modern recipes (skillbuilding) through making verdigris.

From the M&K team we received a verdigris ‘kit’ (see image below):

• 1 sheet of copper ( L x B - 5.5 x 5 cm)

• 1 piece of string (19 cm)

• 1 glass jar with lid (Length: 11.5 cm)

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Chosen recipe:

“How to make the green from brass which is called Greek or common green’ (see image below)

Entry 155, on page 124 of:

Merrifield, Mary P. Original Treatises Dating from the XIIth to XVIIIth Centuries on the Arts of Painting, 2 vols (London: John Murray, 1849), vol. 1.

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Transcription English Translation:

1. How to make the green from brass which is called Greek or common green. — If you wish to make the copper-green which is called Greek, take a new jar, or any other concave vase, and put it into the strongest or most acid vinegar, so as not to fill it and put strips of very clean copper or brass over the vinegar, so as that they may not touch the vinegar or each other, being suspended to a stick placed across the vase. Then cover the vase and seal it, and put it into a warm place, or dung, or under ground, and leave it so for six months, and then open the vase and shake out what you find in it, and on the strips of metal, into a clean vase, and put it in the sun to dry.

Name: Celine Camps

Date and Time:

2018.09.10, 6:00 pm

Location: Private apartment, 405 West 118th Street / Westside Market 2840 Broadway, 10025 New York

Subject: Procuring of materials and tools.

After having selected the recipe, I read it carefully and noted all the ingredients and tools that I required.

The recipe calls for the following ingredients, tools and environmental elements:

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Name: Celine Camps

Date and Time:

2018.09.10, 9:00 pm

Location: Private apartment, 405 West 118th Street.

Subject: Pouring vinegar in the jar

Step 1:
“take a new jar, or any other concave vase, and put it into the strongest or most acid vinegar, so as not to fill it and put strips of very clean copper or brass over the vinegar, so as that they may not touch the vinegar or each other.”

Reconstruction Step 1:

The recipe instructs the reader to take a new jar and fill it (not entirely) with the strongest or most acid vinegar. I have bought Heinz, all natural, distilled vinegar with 5% acidity (see previous image). This was the strongest (i.e. most acidic) vinegar I could find. More time might have enabled me to locate a stronger one.

I wondered how to determine how much vinegar to use “so as not to fill it” and “so that they [the copper sheets] may not touch the vinegar or each other”? I measured how far up the sheet would have to be elevated in the jar, to determine the level of vinegar, by holding the sheet next to the glass. I reckoned 50 ml would suffice.

REFLECTIONS:

• It might be interesting to look for a stronger vinegar and try a variation, to see how the acid level might affect the growth of verdigris.

Name: Celine Camps

Date and Time:

2018.09.10, 9:05 am

Location: Private apartment, 405 West 118th Street.

Subject: Suspending the copper sheet over the vinegar

Step 2: "and put very clean copper or brass over the vinegar, so that they may not touch the vinegar or each other, being suspended to a stick placed across the vase.”

Reconstruction Step 2:

After having poured in the vinegar, the recipe instructs the reader to suspend the copper sheet over the liquid by using a stick (in the reconstruction this meant a piece of string). However, the recipe did not give any instructions on how to do so. I thus paused for a moment to think about how best to go about this. I noticed almost immediately this did not work. While my head was trying to reason through the step of how to elevate the copper sheet over the vinegar, my hands were doing the thinking for me. My thinking was enacted through a corresponding bodily movement. For example, I reasoned: “I could tie the string horizontally around the strip of copper,” and my hands instantaneously enacted that thought by grabbing the string and circling it around the sheet. This is not to say that any noticeable time elapsed between my thoughts and their translation into the corresponding bodily enactment. Rather, they happened in tandem. Even better, the doing was the thinking (thinking with the body as opposed to with the mind)

I thus realized I would have to use a practical or trial and error approach. I tried tying the string around the upper part of the copper sheet in a horizontal fashion. My wearing gloves made this somewhat difficult as the nitrile reduced the sensation in my hands -- and therefore my grip on the string. However, I ultimately succeeded and made sure the strip couldn’t slip down and was securely caught in between the string.

Now I had to suspend the sheet (in the jar) over the vinegar without it falling in. This is when I noticed I got slightly nervous (shaky hands). I only had one sheet of copper. Dropping it would mean the end of the experiment (or having to request a new copper sheet). Like before, reasoning through it did not work and I just had to take a risk. I tried using the thumb and index finger of my left hand to press both ends of the string against the exterior sides of the glass jar -- with the copper sheet suspended in the glass -- then with my other hand, I pressed the lit on top of the string (while still pressing its ends against the glass), trapping it (so the string couldn’t move). Then, I released my thumb and index finger and screwed on the lit (see figure below). I noticed I was shaking a bit, relieved the copper didn’t fall and happy I could start growing verdigris.

REFLECTIONS

• When I read the recipe, I did not expect such a rollercoaster of emotions (nervousness, relief, happiness). My nervousness was of course partly the result of my lack of excess materials. I am curious to know if the intensity of my emotions will diminish through practice.

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Name: Celine Camps

Date and Time:

2018.09.10, 9:12 pm

Location: Private apartment, 405 West 118th Street.

Subject: Growing the verdigris at a warm place

Step 3: ”Then cover the vase and seal it, and put it into a warm place, or dung, or under ground, and leave it so for six months”

I did not have dung or soil, and my apartment is relatively cold, so I wrapped the jar in a towel and let it rest on the windowsill (see image below).

REFLECTIONS:

• I would like to try a variation with pot soil, so as to put it “under ground”.

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Name: Celine Camps

Date and Time:

2018.09.11, 09:15 am

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

Day 1:

After less than 12 hours, the copper sheet has already changed color and turned from copper color to green.

Although its surface area appears smooth, the sheet is not evenly coloured and contains blotches of varying shades of green (see image below)

The vinegar level has remained the same.

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Name: Celine Camps

Date and Time:

2018.09.17, 9:36 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

7 days after start

The color of the copper sheet has deepened and become more intense, giving off an almost blue hue.

The sheet has become more evenly coloured, showing less spots than last week. However, a large semi-horizontal streak of a slightly darker shade of blue/green has appeared on the lower region of the sheet (covering about ⅓ of the copper strip), looking as if wet (see images below). I thus checked if the string was still clamped under the lit and the cover was securely screwed over it, so as to keep the copper sheet suspended over the vinegar.

The vinegar level has remained the same.

I will check again next week.

Variation:

I have procured another jar, sheet of copper and string and will try a variation soon. I will use the same sort of copper sheet, the same kind of vinegar (and amount). But instead of using a towel, I will use pot soil instead (i.e. put it "under ground”.

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Name: Celine Camps

Date and Time:

2018.09.24, 9:03 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

14 days after start

The color of the copper sheet has deepened slightly. Still giving off an blue/dark-green hue (see images below)

The large semi-horizontal dark streak appears to stand in less stark contrast with the remaining part of the sheet compared to last week and it thus seems that it is increasingly becoming of a more even color again. This may however also be an optical illusion due to changes in lighting (My camera settings are not always the same and the light inside my apartment has decreased as a result of the change of seasons).
The sheet’s surface still looks smooth and even.

The vinegar level has remained the same.

I will check again next week.

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Name: Celine Camps

Date and Time:

2018.10.01, 9:35 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

21 days after start

As noted last week, the dark streak has slowly begun to disappear (see images below). Or perhaps rather, the other two-thirds of the copper sheet have become increasingly darker, their color approximating that of the streak.

The vinegar level has remained the same.

I will check again next week.

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Name: Celine Camps

Date and Time:

2018.10.08, 3:00 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

28 days after start

No noticable changes with respect to the color or surface of the sheet of copper

The vinegar level has remained the same.

A bit of condensation has started to appear on the glass jar (see last picture). This might be because of the changing temperature in my apartment. It has gotten colder outside and the heating is not yet on. The jar is wrapped up in a towel, so the temperature of the inside of the glass may differ considerably from that outside, or at least enough for condensation to appear. Not sure if this has any effect on the growing of verdigris, but I will keep an eye on it.

I will check again next week.

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Name: Celine Camps

Date and Time:

2018.10.15, 6:45 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking progress

35 days after start

No noticable changes with respect to the color or surface of the sheet of copper

Still a bit of condensation.

Vinegar level has remained the same.

I will check again next week.

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Name: Celine Camps

Date and Time:

2018.10.17, 9:03 am

Location: Private apartment, 405 West 118th Street.

Subject: Checking Progress

42 days after start

My building turned on the heating this morning. My verdigris, standing atop a windowsill, was located right above the heating. I checked to see if it wasn’t too hot, but unfortunately a lot of condensation has formed in the jar, causing drops to run down the interior of the glass and the copper sheet, ‘biting off’ the verdigris (see image). The vinegar also appears to have discolored somewhat (giving off a blue hue), probably due to drops of condensated vinegar having run over the verdigris and having dropped into the liquid. I have immediately moved it to a different spot-- away from the heating--and removed the towels, so the jar could ‘breath’.

Unfortunately, I don’t have a thermometer in my apartment, so I cannot see how hot it is. It is interesting to see, however, what happens when it gets too hot and the vinegar starts to condensate.

I reckon this recipe probably ought made during the summer as it might be too hot.

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Name: Celine Camps

Date and Time:

2018.10.22, 8:02 pm

Location: Private apartment, 405 West 118th Street.

Subject: Checking Progress

49 days after start

I was a bit concerned last week’s heat would have damaged the copper sheet and the verdigris, but interestingly it looks alright. The sheet has a slight curve and is no longer straight, but there is no visible sign of corrosion, aside from the right lower corner. The vinegar level has not dropped (and least not noticeably).

As for the color of the verdigris, it appears to have darkened, being almost black. However, this might be an optical illusion caused by the lighting in my apartment. Flash photography shows it is in fact still green/blue at heart (see image).

The surface of the sheet still appears to be even and smooth.

I will check again next week.

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