Another Helm Crest Blog

This lovely lady was the person who first introduced me to Cennini. Rachel Grimmer makes an awesome range of projects and is Excellent (pun intended) company. Have a look at her webpage.

Gesso from calcium carbonate vs gesso from calcium sulphate

In my last post, I briefly outlined what gesso was. I am still looking into how it came to be used and why type was chosen over the other. I used the websites listed in the previous post, particularly this e-book, and will refer to it again here.

Calcium Carbonate
Calcium carbonate was typically used in Northern Europe, most likely because this is where significant and accessible deposits were being mined during the middle ages. It is also known as chalk. Chalk is the remains of ancient sea creatures. It can be finely ground and to make chalk whiting. This whiting can be turned into gesso by adding a size.

Calcium Sulphate
Bulian and Graystone say it was typically used around the Mediterranean region, most likely because Bologna and Volterra have large deposits. Jerry Tresser also records that in the 1300s there was a large deposit being mined at Montmartre, near Paris. This most likely accounts for the common name of the refined product: Plaster of Paris.

The mined substance is known as gypsum. This is CaSO4.2H2O [Calcium sulphate dihydrate]

Gypsum was mined, ground up and burned to remove water and any impurities. Tresser says this process also changes the natural gypsum from yellow to white. When this dried product was ground again, it has the adjust chemical composition CaSO4.1/2H2O . It was, and still is, sometimes called Plaster of Paris. This powder is called gesso in Italian.

Gesso was used in 2 ways.
1. Gesso Grosso
CaSO4.1/2H2O + Size
Plaster of Paris, or gesso, was sifted and then moisten it, assumedly with water.

Add parchment size or hide size to this paste to make gesso grosso. This is the first layer Cennini recommends to apply over the leather crest shape. It is fast drying, but this means bulky sculpture protrusions have less time to sag or drip. This makes it a good material for roughing out the shape.

2. Gesso Sottile
CaSO4.2H2O + Size
Plaster of Paris, or gesso, was soaked in water for several weeks
Cennini says to soak it for 30 days. Jerry Tresser points out that this is an imprecise process, as it is not possible to tell when the gesso was been super hydrated. After reading a few other versions of this process, I think Cennini likely chose 30 days as a safe, standard soaking time to ensure the process was completed by this point.

The water is drained off and the paste is set into blocks to dry again. This powder was called gesso di bologna.

Mix it with size to make Gesso Sottile. This is used in the fine finishing layer of Cennini's crest making process. It has the benefit of being slower drying, allowing more time for fine detailing.

What is Gesso , Ground and Size?

Reading Cennini's instructions on making gesso left me confused so I went searching. The best results I found were at Qualitative Study of Cennini's Gesso for Illumination and Wood Coatings: Theory and Practice pp.142-144 The book is available for purchase as a hard copy or e-book. I liked this person's profile and their enthusiasm for the modern version of the process. Here is a summary of my new understanding of the materials and process.

What is a Ground?

When timber or leather are prepared for painting, it is sometimes useful to place a layer of substance that will enhance the surface texture and the appearance of the paint. Gesso is one form of ground. It is a white substance that is painted over the main structure. In the case of crests, Cennini recommends building a structure of moulded leather and applying several layers of gesso as the ground.

What can Gesso be made from?

Sometimes texts simply use the term 'white ground', which is not very specific but is a good umbrella term. The short answer is that there were 2 main substances in use as white grounds, though other less common materials were also suitable.  

Most Common

Whiting    CaCO3 

AKA Calcium Carbonate

- This is available at my local Eckersleys art shop

Plaster of Paris   CaSO4.1/2H2O

Derived from calcium sulphate

*Note* There are several versions of the usable product so I will add detail

This is available at all hardware shops and art shops

Less Common

Kaolin         A2O3.2SiO2.2H2O
Essentially, a clay, but with a wide range of uses and preparations
Synonyms 
- This is available at my local Eckersleys art shop.

Dolomite     CaMg(CO3)2
Magnesium Calcium Carbonate
- I have not seen this for sale but have not really gone looking
*Note* The term dolomite seems to be a synonym for Calcium Carbonate, even though the chemical composition is different.

What is Size?

Size is another word for glue - a very simplified description, but it makes sense in most contexts. Rabbit hide glue, or just 'hide glue', is available online from book making and fine woodworking websites. It comes as orange brown crystal flakes. Cennini recommends making the best size from the "necks of goats and sheep by trimming, washing, soaking and then boiling it," (Thompson, 1960, cited in Bulian & Graystone, 2009, p. 143, linked above). I will have a look at Cennini for the exact quote. This book also mentions two other "historic treatises" by Theophilus and Watin. Both have a preference for animal glue but none mention rabbit skin glue (Souza and Derrick, 1995, cited in Bulian & Graystone, 2009, p. 143). This implies that perhaps we use rabbit hide glue for most of our reconstruction projects simply because it is readily available at the moment, rather than it is readily available because of superior properties.

Clothing from the Decameron: Infants, Children and Youth

Children appear to wear smaller versions of adult clothing. Infants are swaddled - wrapped in bands of fabric. The two teenage girls are wear a form of pinafore over their kirtles. These outer garments are the only items that are wore exclusively by children. 

Clothing from the Decameron: Women

Here is a simple handout I created for a class on clothing shown in the Decameron.

Women's clothing

Underwear

Smock

Rarely visible - sleeves and neck covered by outer clothing. Round neck, no lower than necessary to admit the head. Small pleats centre front on some.

Hosen

Since women do not wear a jack to point long hose to, and since there are contemporary art pieces showing knee high hosen in the low countries, assume the hosen seen are knee length. Can wear footed hose alone or shoes (poulaines or pattens).

 Basic layer

Kirtle

Round neckline, often no lower than the collarbone. Cleavage is never visible. Some worn loose and clearly not laced up (seen being pulled over the head). Others are very tight around the torso. With assistance, it is possible to be pulled into and out of a very firm garment, though side lacing was also known in Germany, France, Italy and other Flemish art of the time. No waist seam. Long sleeves - usually without an opening at the wrist, though buttons and lacing to 2/3 of the way up the forearm was known in the region at the time. No lining it evident, though some show fur at the edges, indicating possible lining. Sometimes 2 kirtles were worn. Upper classes could wear a second kirtle with hanging sleeves. Lower classes tended to wear two kirtles of the same style, for warmth. Ankle to below floor length - again, this increased with the station of the wearer. Excess length was bunched over a belt, worn at the waist.

Outer layer

Houpeland

This outer layer is worn by the middle and upper classes. Working women who require an extra layer for warmth wear an extra kirtle or cloak. The body is cut wide. Pleats are formed high on the waist and held by a belt. The gown can have wide straight, dalmatian or hanging sleeves. No bag sleeves are visible on women's houpelands in the Decameron, though they are present in contemporary art. Collars can be part of a centre opening, standing, low, fur lined or turned down high square. Gowns can be floor length but are often longer. Contrasting colours were used for linings, especially for styles with turn down collars and open hanging sleeves.

Accessories 

Belts

There are 3 varieties of belts worn by women in the Decameron. Hip belts were worn over kirtles. Belts worn over the houpeland layer were sometimes wide, and always worn high on the waist. The belts that were worn to hold up a long skirt were narrow an often decorated. One is shown as black and studded, in a style very similar to men's belts, and another is pictured as coloured to match the gown. Perhaps these belts are of the woven variety, found from the same era. The belts worn over a kirtle, hanging low in the front are often called ovary belts. They pictured with some sort of twisted gold hanging end, in this document.

Headwear

In this document, the only time a woman wore her hair uncovered was when she was in a state of undress, unmarried girls and Queens wearing a crown. The bourelet or padded head roll was worn in many guises, with the extravagance linked to higher status. Some women still wore veils. Working women and older ladies wore simple wrapped styles, while some younger women wore veils supported by hidden structure. The hair was sometimes styled into twin buns above the ears, on either side of the temple. These buns were covered a net-like fabric, and secured with ribbon, crossed on the top of the head. Hoods of a particular style were worn by Flemish women. These hoods had long liripipes (tails) and stiffened brims. The lower edge sat neatly wrapped around the shoulders. These hoods came in a variety of colours, but red was by far the most common.

Shoes

The black, pointy toed poulaine is the most common type of women's footwear in this text. A pair of yellow slippers is visible on a servant. They appear to be made from felted wool. Women's pattens in this document have red uppers, with a single band over the arch.

Pouches

Women are seen with square bags that are suspended from one cord and drawn tight with another two. These can be small or medium sized. There is a shoulder bag, worn by a traveller.

Cloaks

Cloaks are shown in 3 styles: Semi circular with a standing collar, semicircular with no collar (like a mantle) and full (or almost full) circle in a buff colour, with buttons at the shoulder.

Clothing from the Decameron: Men

Boccaccio wrote several texts, though his best known work was The Decameron. This series of 10 tales per day told for 10 days was written in the second quarter of the fourteenth century. It remained popular and was translated into French almost a century later. This edition was illustrated by 2 Flemish artists, who completed their work in 1430-1440. These illuminations provide a fairly comprehensive view of the clothing worn in the Low Countries at this time. There are distinctly French influences in some of the fashions, but the styles and accessories are consistent with other Flemish art of the time.

The following is a hand out for a class I ran. It is a basic overview of clothing worn in the 1430s in the region around Flanders. There will be 3 parts: Men's, Women's and Children's clothing.

Men's clothing

Underwear

Braies

Drawstring waist, trunk style in Franco-Flemish clothing 

Sherte

Full body, long sleeves, always white

Inner layer

Jack / pourpoint

Tight at the waist, bodice separate to skirt

Hose

Separate legs, laced to the inner jack. Seam up the back. Both legs the same colour. Skin tight for all classes of people, bar the very poorest.

Outer layer

Outer Jack

Similar shape to inner jack, but the hose are not laced to them. Fastened with buttons.

or    Robe

Various lengths (floor to above the knee), pleats or folds at the waist, hidden hooks and eyes down the front. Sleeves can be straight, bag or hanging. Can have fur lining or trim.

Men's Accessories

Cloak

The cloak can have a split from the ground to the upper arm or be fastened by 3-4 buttons on the shoulder.

Hats

Chaperon - styled on a hood with a rolled face opening. Bag hats with various height crowns. Some with rolled brims. Straw and felted hats. Acorn hats are shaped like a beanie.

Belts and Pouches

Plain black belts 1.5" wide are the most common. Kidney shaped pouches have their own matching belt. Some other pouches have matching belts. Buckles are rarely seen in this document. Studs and carving are used for ornamentation.

Shoes

Black ankle boots very common among all classes.

Footed hose also common, though only indoors. They have a sole of a different colour, most likely from leather or some tougher material. Pattens were made from wood and leather, and are shown in some outdoor scenes. They can have one or two straps in black or brown. 

Crests in 1450s: Part 3

1400-1450 Austria

http://manuscriptminiatures.com/3963/13535/