Buckthorn sap green Experiment 2, 2016

Merrifield 420 with variables

In 2016, finishing in early 2017, I followed some of the same medieval recipes I followed in 2015 - as well as some new ones - this time using the 'correct' alum and lye as well as a more acidic vinegar.

Adrienne's Experiment steps:

Research

Collect materials

SAFETY FIRST...

Suit up with nitrile gloves, goggles over glasses and N95 dust mask!

We're dealing with some toxic chemicals here: please don't breathe in lye or alum.  They are harmful to your skin, and buckthorn berries are toxic. Try to keep your experiment equipment distinct and separate from your cooking gear.  Trying to stick to a budget?  Go to 2nd hand stores!  Reduce, reuse, recycle!

I found another instruction in Merrifield's Original Treatises in the Bolognese MS De Fiendis Veridibus to make green from buckthorn berries.  It is one that I know other pigment makers have attempted, like my laurel, Mistress Isabel.  Here are some of her early attempts and notes.

This is a picture of Merrifield's Translation of the medieval source:

Bolognese MS De Fiendis Veridibus (Merrifield 420)

Like my laurel, I tried the first instructions, crushing the berries with gloved hands in a glass 'vase'.  I left them in a closed glass jar under the artificial "sun" of a red 60 watt heat lamp and found, like her, that the juice did not 'rise above the berries'.  After five days, it only continued drying out.  I closed the ball jar and ran away to do other things for a while.

Almost three weeks later, on the ninth of December 2016, I noted a strong winy smell when I opened the jar.  My notes indicate that when I measured the system (jar, berries and lid with label) on 12/9/16 it had lost less than 4g from evaporation from the first time I measured the system but my scale seems to go up or down without ever stabilizing sometimes and I suspect that it's more than just wind, breath or random evaporation.  Some day I'll have to replace it.  For now I just carried on.

To the winy berries I added 10.39g of distilled water (DW) to the jar, trying to rinse down the drip I had left from scraping juice from my gloves after crushing the berries initially.  That was a little more DW than I intended but I got a little carried away trying to rinse the drip off.  After rehydrating the berries I scraped the rest of the drip down then stirred it with a plastic fork and left it to sit and re-saturate until 12/22/16. 

I boiled a piece of previously used and washed cheese cloth to sterilize and pre-moisten it to strain the juice from the berries.  I sterilized a new ball jar for the forthcoming juice then poured the berries from the old jar into my clean, moistened cheese cloth in the new clean jar, then picked up the berries by the four corners of the cloth and squeezed out the juice through the cheesecloth with a gloved hand.  The moistened berries yielded 20.68g of juice.  I noted that when I squeezed them out there was a little juice that squirted into the sink from between my fingers and that some was left on my gloves again too.

From Mistress Isabel's notes and my own research I discovered that a cursory search reveals that a few quattrini finds weigh somewhere between 0.39 and 0.6g.  A note in Merrifield explains their value but doesn't discuss their mass (Merrifield 420).

Then two quattrini/o should weigh between 0.78g and 1.2g.  The recipe says to use two quattrini for a pound of juice.  The juice I extracted weighed only 20.68g. That is a very small percentage of a pound but I figured I could push it to make sap green anyway.  I added one small spatula scoop of potassium aluminum sulfate (rock alum) that weighed 0.12g and swirled the liquid in the jar by moving in a circle while the jar remained flat on the table.

Wanting to see immediate results and wondering what would happen if I skipped steps, I swirled the jar for a while then painted out some of the juice with commercially available gum Arabic and a few drops of distilled water. I then proceeded to introduce other variables such as calcium carbonate and lye to compare the results.

First Results Merrifield 420

The buckthorn juice alone with rock alum mixed with a little commercial gum Arabic (as a binder) and a little distilled water painted out reddish and turned blue as it dried on Strathmore bristol (vellum finish).

The medieval manuscript suggests "distemper it with clear lye..." if it dries up.  I wondered what adding other carbonate containing chemicals might reveal and tried a trial in clam shell (rather than the plastic wells of my palette), a pinch of lye, K₂CO₃ as well as a pinch of crushed eggshell.  The two calcium carbonate sources revealed an immediate gentle sap green and the lye an olive tone. 

By the next week the blue had turned dark green.  Further experiments with the colors in the palette can be seen in the next blog post.