'vergaut'? Blue and yellow make green!

The term 'vergaut' was introduced to me by Elena Wyth when she asked a question about mixing indigo and orpiment on Facebook. I hadn't come across it before, so I went to the books!

There seem to be many medieval instructions for mixing orpiment and indigo but few call it vergaut, as far as I can see. Read more below to see what a brief search helped me find.




In what I have come to call 'the big book of Merrifield's recipes'  vergaut is only listed once in the index which points to this passage: "Vergaut est color qui est quasi ut azurium respectu coloris, non respectu materie." Despite four years of high school Latin, I have little idea of an appropriate translation and the search engine translation is not much better... Perhaps it's not Latin at all?

The note on Merrifield's passage says "Vergaut. See Eraclius, No. 282. Perhaps Vertbleu." (Merrifield 1967: 38)

So, down into the rabbit hole we go! Merrifield's big book has a translation of Eraclius' MS and No. 282 says, "Mix orpiment with azure or indigo, or ocher with indigo, or green, and it will be good 'vergaut'...." (Merrifield 252)

I guess I should always look in the glossary S. M. Alexander supplied/compiled for Merrifield's tome. He defines it as "Vergaut. Grey-green colour made by mixing "azure" or indigo with orpiment or yellow ochre." (Merrifield xxxiii)

Other than modern pigment analyzers I only see the term 'vergaut' in Ms. Merrifield's book but here are some other instructions for combining indigo and orpiment...

We have various translations of Cennini Cennino's book Il Libro Dell'Arte and his book definitely has instructions for green from indigo and orpiment. Society lady Christiana Jane Herringham and researcher Daniel V. Thompson Jr.'s copies are both useful and valid versions. In her introduction Ms. Herringham mentions a less complete translation by Mary Merrifield which I have not found or read personally. I am drawn to the most recent translation by Lara Broecke. Her references and notes fuel my curiosity and direct my perseverance.

Lara Broecke's translations: "[Orpiment], mixed with Bagdad indigo, makes a green colour for grass and for greenery... at first [orpiment] is the stiffest pigment to mull that there is in our profession.  However, when you want to mull it, put the amount you want on your stone and, with the one that you hold in your hand, start loosening it up little by little by squashing it from one stone to the other, mixing into it a bit of glass from a broken drinking glass because the glass powder starts drawing the orpiment into the texture of the stone... if you mulled it for 10 years it gets more perfect all the time... Watch that you do not spatter your mouth with it lest it does you harm."(Broecke 73)

Notes
There are notes about words on the document being translated then...
1. Orpiment is arsenic sulphide with approximately 60% arsenic. It is found naturally in Italy and was known to Vitruvius, in the first century BC, as a natural pigment (Vitruvius 1914: 7.7.5). However orpiment could also be manufactured by the sublimation of a mixture of sulphur and arsenic trioxide (FitzHugh 1997a: 55).
...
6. other treatises mention the use of oil, gum and egg white (the latter two in the context of manuscript illumination) (Merrifield 1849, 1: cliv).
...
9. Glass can help with the grinding process because it breaks up the fibrous structure of the mineral (Cennini 2006: 264). Ground glass has been found as an additive in paints, mordants and grounds on Italian  paintings of the fifteenth and sixteenth centuries and experimentation has shown that it can act as a drier as well as altering the working properties of paints and their surface texture when dry... (Broecke 74) This note keeps going and is interesting and relevant but perhaps talk to me about it later and you should definitely buy a copy! So worth it if you're a pigment geek like me!!

"Chapter 53 On the way to make a green from orpiment and indigo
A pigment which is made from two parts orpiment and one part indigo is green; and mull them together thoroughly with clear water. This color is good for painting shields and lances and is also used for painting rooms in secco. It should have no binder other than glue." (Broecke 80) 

"Notes: 1. The Venetian Manuscript gives different ratios; three parts orpiment to one part indigo for making 'green' and three parts indigo for one part orpiment for making 'dark green' (Tosatti 1991: 235).
2. Mixtures of orpiment and indigo have frequently been identified on paintings (FitzHugh 1997a: 53). Alcherius gives detailed instructions for making this mixture, which he says can be used for fabric, parchment, paper and primed panels, but he recomments egg white or gum as a binder rather than glue. He notes that an even better green can be produced by mixing ultramarine with orpiment, a mixture that Cinnino discusses in chapter 55 (Merrifield 1849, 1: 272-40). The Liber diversarum arcium has this mixture bound in egg white or gum or both (Clarke 2011: 105, 121) and the Bolognese Manuscript has a mixture of indigo and orpiment bound in gum (Merrifield 1849, 2: 420-21.) The difference in binders is probably because the sources mentioned in this note focus on manuscript illumination while Cennino's recommendation to use glue as opposed to egg yolk as a binder may be intended to preserve the natural sparkle of the orpiment (see chapter 47, note 6)." (Broecke 80)

Cennino warns of orpiment's toxicity a number of times. It's interesting and a good cautionary note for certain! Personally I might stick with indigo and ochre...

In the Strasbourg Manuscript, a chapter about incompatibilities suggests both things you should and shouldn't do with orpiment "but indigo, or light blue azure could be mixed into oripiment, that does not damage it and it becomes beautiful (colour), for drapery, for grass and for mountains." (Neven 123)

And in De Arte Illuminandi still more about 'why not' on parchment.

Papers from the Journal of Raman Spectroscopy that do just call it 'vergaut':

Identification of pigments and gemstones on the Tours
Gospel: the early 9th century Carolingian palette Clark et al.

The Lindisfarne Gospels and two other 8th century
Anglo-Saxon/Insular manuscripts: pigment
identification by Raman microscopy Brown et al.

Analysis of key Anglo-Saxon manuscripts (8–11th
centuries) in the British Library: pigment identification
by Raman microscopy Brown et al.

Those interested in digging deeper are encouraged to  continue to mine the notes and references! To conclude this slightly disorganized and admittedly incomplete review I would encourage the reader to take these notes for what they are and pursue further research as appropriate.