2016 Buckthorn with vinegar paint results

Here are the paint results from these buckthorn and vinegar recipes in 2016.

 

I was able to make a nice sap green from the buckthorn with white wine vinegar by adding a little potassium aluminum sulfate (alum).

Note that the 25% acidic vinegar and buckthorn produced a thick juice that required more thinning and would require more water and more gum Arabic to produce a smooth paint.

When I added alum to both buckthorn and vinegar recipe it resulted in green!  By itself, the results were less satisfying and not what I would call green but more blue gray.

Side note: I think the shininess on the first two swatches is the result of a little too much gum Arabic.

2016 sap green from Buckthorn Experiment 2 Results

This experiment began in November 2016 and was finished up at the beginning of 2017.

The ripe buckthorn, Rhamnus spp., juice had been extracted from refrigerated, and slightly dessicated buckthorn berries from Saco, Maine. The berries were reconstituted with distilled water (DW), and then rock alum (potassium aluminum sulfate) was added to the juice.  Commercially available gum Arabic was then used with distilled water to paint it out on 12/23/16.

By 12/29/16 the dark blue had turned to dark green and further trials were performed. 

The change of color from blue to green suggests a few possibilities to me.  Either the alum had a chance to change the buckthorn after sitting with it for a while or it could have come into contact with calcium carbonate contaminates from the enviornment like egg or clam shell (neither of which are scarce in my house) or the Strathmore Bristol vellum finish paper is prepared with a buffer that reacted with the acids and berry juice. 

Further trials were painted out from the original berry juice with alum in the palette and shell with gum.  More distilled water was used to re-hydrate the paint and thin it out for greater visibility.

The juice with alum alone, in a clam shell and with crushed egg shell all yield what I would describe as a gentle sap green.  The trial with lye turned from a rather interesting olive to quite a bright yellow reminiscent of the yellow yielded from the green buckthorn drupes and in another ripe drupe recipe discussed here.

Iris Green 2016

Last year for my pigment experiments I used aluminum sulfate from a dye company thinking that was the right kind of alum.  In 2016 I made Iris green clothlets with the medievally recommended alum, Rock Alum, which I learned is aluminum potassium sulfate or potassium aluminum sulfate, KAl(SO₄)₂·12H₂O.

Iris Green Clothlets 2016 from De Arte Illuminandi

 Click "read more" below to find out how!

Buckthorn yellow 2016

This year I decided to try using concepts from De Arte Illuminandi to try unripe, green berries to make yellow, a possibility indicated by the translators.

Two pigments were and are derived from Rhamnus berries; a yellow and a green.  The product of the unripe berries is the Giallo santo (cf. M. P. Merrifield, op cit., I clxiv), known in English by the extraordinary names, "Italian Pink" and "Dutch Pink."(Thompson and Hamilton 43)

That page of Merrifield's text explains,

 Giallo santo was a kind of yellow lake, which was made from various plants.  It was sometimes prepared from the berries of buckthorn (Merrifield clxiv)

and the result is reinforced by the Pigment Compendium that explains,

various species of the Rhamnacea family give a yellow dye on extraction of the unripe berries (drupes)

 It seems that the medieval artists more commonly would have probably used the local ochers from the land or orpiment, arsenic sulfide, or one of the lead yellows... but I have buckthorn berries from Saco, that I picked, for free, and don't feel like playing with arsenic or lead today!  

Here's a preview picture of them, 

yellow clothlets from green buckthorn berries in the foreground, sap green clothlets behind

And now I'll explain how I made them, just click 'read more' below.

Buckthorn 2016

It's nearly the 'vintage season' again and that means Buckthorn berry recipes!

Sap Green Buckthorn clothlets 2016

 

Rock Alum

This is my silly "rock alum" saga. 

The bottom line is that alum in medieval paint recipes is Potassium Aluminum Sulfate KAl₃(SO₄)₂(OH)_6.  

Read on for how I learned this.

Iris experiments 2015

Today (3/26/16) I taught my period pigments class again and we played with some of the pigments I made in 2015.  Re-reading this post today I realized that I have learned a lot since then and need to update you all with a new post.  I promise this will happen soon after Easter, aka tomorrow.

In the meantime you can explore my page of references, here.

Collecting the blue iris blossoms as they bloomed, May 30th, 2015 for over a week, I ended up with several hundred flower heads in two gallon sized zip-lock bags.  Taking the advice of Wendy Feldberg, I froze them for later use.  Though there were not freezers in medieval Europe, this seemed like a reasonable compromise with modern obligations.

The chemicals and linen I ordered from Dharma Trading Co. arrived!  I used the wrong alum in these recipes, aluminum sulfate.  It should be 'rock alum' which is evidently potassium aluminum sulfate.  In 2016 I used the correct alum with pretty much the same results.  Blue clothlets when they were wet changing to green the more they dried and painting out green.

I washed all of the linen with modern washing machine soap (Free and Clear Tide) and a 1/4 cup of white vinegar.
Not sure of the weights of medieval linen I ordered a yard of each of the three weights available from Dharma Trading Co. 3.5oz, 5oz and 8oz for making clothlets.

In the Materials and Techniques of Medieval Painting by Daniel V. Thompson, iris green is described (171).  Clothlets are mentioned but not well defined and the process is never described.

Courtesy of Clair Turner I learned that the Glossary of the British Library describes it in depth:

CLOTHLET

A piece of cloth impregnated with PIGMENT (generally a vegetable dye). A portion of such cloth, when soaked in a little BINDING MEDIUM, releases its colorant and produces an artist's pigment. Clothlets are called petiae in Latin and pezze or pezzette in Italian; bisetus folii refers to clothlets dyed with folium, or turnsole, extract. Clothlets were a convenient way of carrying or shipping vegetal pigments, and they were especially popular from the fourteenth century on, with the growth of the textile trade. Glazes of vegetal dyes were often used to enhance other colours in book ILLUMINATION, since they created a rich, glowing, and transparent effect.


Randy Asplund then clued me in to Mary Merrifield's Original Treatices and there I found my recipes. 

Based somewhat on the recipe translations in her book I made clothlets and prepared egg shells and clam shells with iris juice and a pinch of alum.
I was excited to get started and in a hurry to get something accomplished so I did what all of my friends and family would tell you I do with all of the recipes I work with:  combine techniques from several sources and hope for the best, modifying behavior for the next round based on results!
Also found references in the anonymous treatise  De Arte Illuminandi (translated by Varney pgs 7, 15).

And the paint results from August can be found here: