Date and Time:
2015.12.2, 10:10am
Location: Chandler LaboratorySubject: Verdigris dye preparation
10:40am- All materials gathered. Using the lab's verdigris which seems to have a very blue hue; I'll be interested to see how green the dye becomes. The recipe only specifies white vinegar, but other recipes for green dye in our manuscript (fol. 78r_3) and other manuals tend to specify "strong" vinegar, so I am using a white wine vinegar with the highest percentage of acidity (7%) I could find locally.
10:55am- Curious to see if the verdigris will dissolve in the vinegar and what color it will turn. As a test I added about 20 ml of vinegar to a beaker and about 1 gram of verdigris. After 5 minutes of constantly swirling the mixture the vinegar turned a light blue-green color but there are still verdigris crystals that haven't gone into solution.
11:00am- Placed the small beaker with the vinegar verdigris mixture on the hot plate set to 1. In less than 5 minutes the remaining verdigris crystals went into solution and the color turned a darker green color.
11:00am- Combined 2 cups white wine vinegar and 14 grams verdigris in large beaker. Placed on hot plate set to 1. Notice the gradual change in color from an almost teal blue to dark green.
11:20am- Gradually increased temperature of hot plate. Heated vinegar/verdigris solution until about 70 degrees C, then added 14 grams potash alum. I gradually added the alum at first, but unlike the madder root dye there was no effervescence, so I just quickly added the entire remaining amount.
11:30am- The dye has turned a much darker green color (it seemed to get progressively darker after adding the alum and remaining on the hot plate). Removed dye from heat once temperature reached 90 degrees C.
11:35am- Added dye to jars until veneers completely covered, and any remaining dye to a labeled jar placed in the fume hood. After disposing cleaning beakers and disposing rinsewater in labeled waste container I returned home and added jars to the hot dye bath containing the red dye samples from last week. I noticed a strong, pungent smell coming from the crock-pot when I removed the lid, so I assume somehow a small amount of the madder dye must have leaked from the sealed jars. The temperature of the hot water bath was still about 150 degrees.
Compare the color of the prepared dye (heated to 90 degrees + 14 grams potash alum) to the color of the test vinegar/verdigris solution from earlier. While some of the difference in color is likely do to the amount in the jars, my camera's settings, and lighting, the prepared dye is a darker green color and seems more opaque.
