Saturday, November 02, 2013

Cheese Molds pre-1600

Cheese is an ancient food.  There have been a few new finds that date this food stuff to neolithic times. A shard that was part of a cheese mold was carbon dated in order to figure out how old it was.  I find the interesting part, as always, are the archaeologists trying to figure out how it was used (and if it was a shard, what the whole piece might of looked like when complete).

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With many ceramic objects from ancient times (and before) that figuring out how something was used is pretty tricky. It's all guesses unless there is some sort of detailed writings during the time period it was made.  Usually every day use of some objects just weren't discussed.  We only use modern interpretation of what we know of the uses of the object and any other documentation we may have from previous sources. Analyzing the object for any residue, such as various food compounds, help with identifying what the object was on contact with.  That helps in the identification process.

Ancient cheese molds are actually a fairly interesting object.  Faisselle (Cheese strainer) is another name for a bowl with holes to allow whey to drain from the curd. They come in different shapes and sizes. The word comes from the Latin fiscellae. These strainers were originally made from bisqued clay, stoneware or porcelain, and later in wood, iron, aluminium, and plastic.



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Two more related words:  FAISSELLIER : instrument used for pressing curds in Neufchatel cheese.
FAISCINE : (related to Faisselle, Latin origin) meaning a whey mold, used in the region around Tours.

These molds (moulds) could have had some sort of weight added to them. Adding weight would make them presses, but as there hasn't been any pieces found that would fit within the mold as a press, it's difficult to rule that use in or out. Perhaps they stacked on top of one another, however usually if there is a stacking pot, the foot and lip are adjusted in the creation so that they "lock" in place making them more stable.  I haven't seen the underside of any of these pieces, so it's though to say if that was done.  From what I can see the lip is flat and the walls are straight.  So, while they could stack, boy they would be easy to knock over.

Since none of the potters are alive that made these pieces, its really tough to say why they did what they did.  Pottery even in ancient times was fairly advanced. Ceramics haven't changed a whole lot since the wheel was created (save a number of firing and some other techniques which came from leaps of technology in various areas of mining and production).

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Netherlands, 1600-1700

These are the main shapes that were locked into "cheese molds" but other items can be used for the same thing.  Late period, in Brittan, there were colanders that looked very close to an illumination which shows cheesemakers.  The archeologists aren't always right.  Anything with holes can be used as a mold and if you can fit in weights, a press.

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Friday, April 05, 2013

Better than me


I am a competitive person.  I can’t help it.  It’s how I was raised.  The problem with me is that I’m not very good at a lot of things, only a handful.  Any physical tasks, you should pick me last.  I’m good with that.  I do have my quirky specialties.  Those are what get me pretty annoyed that someone else might know more about it or might be just better than me.  It happens.  I am first to admit that I am not the best potter in the world.  I can always find someone else that is better than me.  Which gets me mad, not at them, but at myself.  I figure that the amount of time I put into something, it should equal “better than” on anything.  But time doesn’t mean anything in any given field I’ve noticed. It’s talent.

For me, I think my painting skills are just ok. Sometimes things I do are really awesome, but others, it’s sort of mediocre.  I’m purposely coming up with projects that I can practice and improve my work.  When I was in college, Decoration was far more important than the creation of the piece.  I did some time consuming projects, both in glazing and in the altering of the clay surface.  Over the years my throwing became more of the focus and became stronger (with practice).   One of the things I’ve done was forcing myself to throw things in one piece whenever I can, instead of two.  I’ve figured out some really crazy shapes over the years that in period molds were used because of gravity problems.  Clay and the wheel rely heavily on centrifical forces as well as plasticity of the clay, which is a real challenge to figure out. I’m far from perfect at it, but I am so far ahead of where I was when I started.

I used to be a musician for about half of my life.  I played numerous instruments and was a voice major at Cal State Northridge.  I was ok at the singing part.  I naturally sing slightly flat.  Bothersome.  But I had a very smart teacher that told me, “Practice does not make perfect, it makes permanent.”  The idea is that if you practice the wrong thing, not matter how LONG you have been doing it, it’s still wrong AND it’s hard to break bad habits.

I’m not sure if it is just a ceramic thing, but I can’t tell you how many people I’ve met over the years that have immediately told me how long they have been doing pottery.  I guess they are doing that in order to justify an opinion. I’m not sure in other cases why.  To me, anyone can have an opinion about my work or anyone’s work (doesn’t matter if they’ve done it or not), but it’s my job to consider whether the comment is valid or not. I’ve been cooking all my life, that doesn’t make me a chef. I’ve learned that just because someone had done pottery for over 25 years, they may not know about period pottery.  Time doesn’t equal perfect, being good at it or knowing more than everyone. 

Talent makes you good.  Studying and learning make you better. Time does give them the opportunity to study and hopefully perfect in whatever their focus is.  In Ceramics, there are myriads of aspects.  I don’t think one person can be a master of all ceramics.  Ceramics has many layers, from the construction of the piece, to the decoration… both of those sound simple, but construction of a piece is not just throwing.  You have many options (throwing, hand building, molded…) and then you have decoration (surface decoration on the clay surface before it is fired to bisque, then you have many ways to color and alter the object after bisque).  Most clay artists seem to gravitate towards one aspect or type of ware and stay there for several years perfecting it… then move along.  However, there are numerous potters that are known for their luster glazes (Beatrice Wood), for their Salt Firing, for their maiolica, for their altered works, their sculptures, their large forms… anything and everything you can imagine, someone does it REALLY well.  Narrowing the field in order to really master it.

I’m confident that I will continue to try new things, try to perfect older techniques and be the best that I can.  I just have to remind myself that other people can do the same thing I am doing… and not feel pressured into competition with them.  The only person I should worry about is myself.  That’s a hard lesson for me. Wish me luck.

Tuesday, April 02, 2013

It's more difficult than it looks: Cracking & Explosions

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Next in my series of posts on "It's more difficult than it looks" comes something very natural to most clay -- cracking.

There are a few things that most people may not know about clay.  First is that "clay has memory"... meaning that the clay platelets that make up clay needs to be completely mixed evenly or else any settled clay may form cracks.  These cracks can form in the drying or more annoyingly in the firing stages.  Unevenness can happen if a piece is bumped, banged or pressed between the forming of the piece, all the way up until it is bisque fired.  Some clays are more forgiving, allowing slight mistakes in how it was handled, but others less plastic like porcelain, crack.

Cracks come in all shapes and sizes.  As with the example I found online, this one looks to be due to possible different thicknesses of the piece (uneven) and possibly a compression of clay wasn't done as well as it should have been.  These types of cracks aren't the type you can usually salvage.  If it cracked as it was drying, you can at least melt the piece down and reuse the clay.  If it's fired, if you have the right equipment, you can grind up the bisqued item into grog which can be used in clay to make the clay more workable.  Most people, however, just throw out those broken pieces.

I bring up explosions.  It's exactly what you'd think it is by the name.  Pots will explode in the kiln with much vigor. When air and moisture is trapped in the clay as it is fired in a kiln, the fast evaporation shocks the piece and will cause said explosion.  Explosions can be small or large enough that the shattered pieces can fly into other pieces, breaking them.  Pieces need to be bone dry before they are fired as well as a slow, even kiln firing.  Too fast of a ramp up can cause shock to the pieces.

So, sometimes someone else can damage your piece without them meaning to.  This just adds to the sometimes unpredictable nature of ceramics.

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Monday, March 18, 2013

Techniques for recreating Maiolica (Tin Glazed Ware)


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I was asked recently how I do my maiolica. I need to preface as I've been doing maiolica on and off since I started playing in clay, but with all this time, I am by all means no expert.
Maiolica is the Italian name for tin glazed pottery. It was supposedly named after the island of Mallorca, which is where much of these pots originally were traded. The idea of tin glazing when it was being developed around 9th century was to replicate porcelain, especially the very popular Chinese blue-on-white ware. Porcelain is not an easily found clay throughout Europe and the middle east pre-1600.  

Piccolopasso wrote a book which described the period techniques of Italian maiolica in the 16th century. As with many glazes of the time, lead was a flux (helped the glazes melt at certain temperatures) and tin was used as a opacifier.

The idea of tin glazing is taking a bisqued clay surface (usually either gray or red earthenware was used) and covering it with a white base glaze. Colorants are used to decorate the white pot, then fired together. The white (blanco layer) and underglazes meld together to form a unified, smooth surface. There was also the technique of using a clear across the decorated piece.

Tin glazing is a very specific technique. In the middle east, there were techniques that they did in order to get a white base and decorate, however most of that didn't use tin glazing. Much of that was either using Fritware (which is a porcelain like clay body, only closer to feldspar, thus it's name) or a white slip as the base (slip is a watered down clay to a milkshake consistency).

There are numerous books and videos on this very popular technique.  Modernly, there are numerous ways to achieve the tin glazed look. The first, and most obvious is use a tin glaze and then use stains for the colors. There are many recipes online for good "maiolica" glazes as well as how to use the stains/colorants. 

Here is a link to Linda Arbuckle's Maiolica base glaze which fires at cone 04. 
 http://ceramicartsdaily.org/ceramic-glaze-recipes/low-fire-glaze-recipes/linda-arbuckles-majolica-glaze-recipe-cone-04-oxidation/

And another with colorant information: http://ceramicsweb.org/articles/arbucklemajolica.html
If you can't mix your own glazes, there are numerous glaze companies that make "maiolica" specific glazes and underglazes/colorant/paints that are compatible. Duncan makes a white base glaze that works fine. They have a few available. Contact Duncan for over glaze compatibility. Their EZ line (ez stroke) works well for the colored sections and it does work with the Arbuckle base.  Duncan IN1653 Downright White is a reasonable base.

Colorobbia  (and Italian glaze company) has a Maiolica White and an entire line of compatible underglazes (Bellissino line).  Aamaco has an entire line specifically for tin glazing (check out their majolica gloss glazes... They have Decorating Color sets that all work together).

My experience has mostly been with my own mixed maiolica base glaze which is similar to the Arbuckle base. I've used Duncan bases in the past as well, either a white base like the Downright White and EZ paints or I used the Duncan concepts (Artic white 101 as base and the rest of that line to decorate, then a clear across everything to seal. All Duncan.

The underglaze route with the clear is something I've seen the majority of historical potters do. They are very reliable and I've used them for over 15 years doing many different techniques. There are many ways and resources for this technique. It's always best to do test tiles and experiment first with any new glaze to make sure you understand how they work before you commit it to a full piece.

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Friday, February 08, 2013

Botijo

From Wikipedia:

A botijo or búcaro in Spanish, a càntir, pitxell or poal in Catalan, is a traditional Spanish porous clay container designed to contain water. The botijo has the property that once filled and placed in the sun, it cools the water that it contains, acting as an evaporative cooler.

The botijo has a wide belly and one or more mouths where it is filled and one or more outputs called pitón o pitorro to drink from. The botijo is a typical element of Spanish culture and may vary in shape, color and material.

The operating principle of the botijo is as follows: the stored water is filtered through the pores of the clay and in contact with the outside dry environment (characteristic of Mediterranean climate), it evaporates, producing a cooling (2.219 kilojoules per gram of evaporated water). The key for cooling it, is by the evaporation of bleed water, as the water evaporates, it extracts thermal energy from the water stored inside the jug (and from the environment itself too).

BotijoforJuanna_zpsba7667a0 photo BotijoforJuanna_zpsba7667a0.jpg

Made by Alex de Vos

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Teruel Botijo

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Sunday, January 20, 2013

Scratchy? Stoneware for the privy

This is a great example of archeologists and how they guess at what and how ceramic objects are used. I am not convinced that this is what the use is. I'm pretty sure they can run tests to see if there is any material left in the unglazed ceramics that could confirm.

Why I don't believe it's use...There would be thousands if not more of these things found if they were used for what they are saying.

Depending on the shape (I can't tell by these horrible photos) I could see a skin scraper (exfoliation). Those were used in bath houses in the middle east and could see the Romans stealing that idea to make their own of sorts.

This is always the challenge for a historical potter just figuring out what to trust. I have numerous books printed many years ago that have wrong information (newer books have proven opposite info) and vice-versa. Over the years you just have to go with those ideas that make the most amount of sense to you and hope for the best.

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Saturday, December 29, 2012

Everything you needed to Know about Ceramics but were afraid to ask!

Ceramics is one of the oldest art forms known to man. As far back as Neolithic Period, people have been making ceramics. Most clay objects found from early periods (21st century BC and older) were mainly utilitarian or ritual vessels, and vessels have since been the main stream of several countries ceramics industry (foremost in China). Clay is a soft, sedimentary from rock (igneous) that had been eroded into a mud-like consistently by weather and break down. It is fire that solidifies the chemicals of the clay, melding them into one package. Once fired, you’ve basically created your own rock! The colors, textures and plasticity (the capability of holding a shape when fired) vary from almost translucent white, varying shades of orange to brown and even black clays. Over the centuries, clay has also been used as cosmetics (face powers and foundations) and more importantly medication.

One of the major ingredients in some clays is a chemical known as Kaolin that was used for stomach aliments (the main ingredients in most clays are silica and alumina). Modern world, you may know it as the product Kaopeptate. Prior to the 4th millennium BC, all ceramics were made by hand, especially by way of coiling. This is rolling clay snakes or coils out (like ropes), then stacking them one on top of the other to finally smooth over the coils (where the coils meet) together, eradicating the joints between coils. Sometime during the 4th century BC, the potter’s wheel was invented in the coastal region of northern China. Potter’s wheel is basically a rotating disk, which provides the momentum while a lump of clay that is centered on the disk is manipulated. The forms that are made from the wheel vary, but most of the objects are round in shape, such as bowls and vases.

In parts of Turkey and the Middle East, some of the wheel designs that were created in the time of Christ are still being used to this day. Molding also developed in Neolithic times. Wet clay was pressed against a mold, made solid, and then withdrawn from the mold. This made elaborate shapes and complex decorations possible. As the years went by, molds were made out of many different material (mostly wood and plaster). Clay is fired at different temperatures depending on the chemical composition of the clay. There are three basic types of clay bodies: Earthenware, Stoneware, and Porcelain. Earthenware is considered a low fire type clay which is porous and permeable. (fired between 600c to 1,100c). Stoneware and porcelain are high fired and the body fuses, becoming impermeable and extremely dense (stoneware fires between 1,200c to 1,300c, while Porcelain can fire up to 1,400c).


During the Middle Ages, it was Asia (mostly Korea, China and Japan) that had Porcelain and used this white clay body to their advantage B having such a white, translucent body was much revered and all of Europe was jealous of such fine materials. Porcelain was a major export item and China’s detailed plates using cobalt (blue) and red oxides were the talk of Europe. Porcelain because of it’s high failure rate (more breakage when using the clay body when it dries and fires) is still highly revered. Clay is used in our mouths (porcelain fillings) and in space (silicon-based ceramic tiles on the space shuttle). It’ not just for keeping your coffee warm anymore. Pretty impressive for a little pile of mud, huh?

There are numerous forming methods that are used. Some of them are: coiling, slab building, throwing, jiggering (which is very similar to wheel throwing) and casting. Coiling is taking clay and rolling it into little “snakes” or rope “coils” which are then put into the desired shape, and then smoothed together. Some of the earliest pottery found was made in this manner.

Slab building is rolling out a piece of clay flat, like a piece of paper (except not that thin) and then using. A jigger has a wheel head that spins a mound of clay around, and another device that is used in conjunction with the rotating wheel head that is a mold. The mold is pressed against the spinning clay and it cuts away the excess, making it easy to duplicate shapes.

Casting is using molds (normally plaster) and a watered-down clay mixture called slip is poured into the mold. Once it is dry enough to move without damaging it, it is pulled out of the mold and allowed to dry completely, then it is fired.

There are three stages of ceramics: greenware, bisque, and glazeware. Greenware is an unfired, formed piece. Bisque means “half baked”, which is basically a piece that has been fired to a temperature which turns it hard enough to glaze but not too hard so that the piece’s pores close (you need them open in order for the wet glaze to hold firm to the surface). Pieces should be bisque fired before glazing to avoid blow ups or glaze discoloration. Some pieces, such as flowerpots, are not glazed – you don’t have to glaze pieces if you don’t want to.

To make a piece sanitary (i.e. able to eat food off of) one needs to glaze the piece in question. Glazeware is when a bisqued piece has been glazed and fired. A glaze is a mixture of chemicals, mostly silica (which is the major component of glass), clay, a melting agent, water, colorants and a suspension agent (which allows the chemicals to stick together and not separate like oil and water). Depending on the chemical composition of a glaze, when it fires against a bisqued piece, the glaze will turn glass like and in high fire glazes, will merge with the vitrious clay. There are various types of glazes and items to help decorate: opaque, translucent, semi-opaque, over glazes, under glazes, engobes (a slip that has been colored with stains or oxides, used on greenware), metallics, lusters, high fire, low fire, matt and glossy. Some glazes work well with each other, while others need to be used by itself.

Glazes are brushed on, pieces are dipped into glazes, or the glaze is poured across them. There is also spraying (basically a special air brush). As with painting and dying clothing, wax is used as a resist technique, so whatever the wax touches, the glaze will not stick to it. Clay is a great medium with hundreds of possibilities for forms and decorations.

Let’s now go into more details on how that effects your persona and life in the middle ages. The majority of the people that lived in the middle ages did not have a whole lot of money. Keeping this in mind, clay was an inexpensive material that could replace many of the expensive metal items and lasted longer (and was far more sanitary) than wood products. In Asia especially, ceramics were used everywhere, from temples to the farmer’s dinning table. “The Way of Tea” was an honored ritual, which focused around tea and its presentation. Korea, China and Japan were instrumental in the development of porcelain. For this ceremony, the tea bowl was a specific design, with each section of it done just so. At the end of our middle ages (late 1500) a potter in Japan accidentally stumbled upon a new glazing technique called Raku, which was used exclusively for “The Way of Tea” and the emperor of that time honored the potter. Only in the past 80 years did Raku come to America (brought to Great Britain first by a potter named Bernard Leach) and there is still a “Mr. Raku” in Japan, 15th generation of the first potter, making tea bowls.

In Europe, however, they were using earthenware. Remember that porcelain is a white, dense clay which was higher fire, in comparison to the porous, lower fire earthenware (whose colors range from beige to brown). Earlier in period, the Romans and Greeks used a decoration technique called Terra Sigillata, which was a refined slip (extremely strained clay that was skimmed for the purest deposits) that was brushed across an unfired vase, burnished (or naturally burnished by nature), fired and glazed. Later, when Tang Dynasty ware was extremely popular, a technique was developed in Mesopotamia between the 9th and 10th centuries called Maiolica (sometimes referred to Majolica, Delftware, or Faience) which earthenware is taken, formed and fired, and a white, thick low fire glaze is applied. Then, stains or oxides (which are pigments that are used to add color) are painted across the white glaze. Once it is fired, the oxides and the base glaze melds on the earthenware, making it look like a porcelain piece with colorants brushed across it.

The general populace could afford these pieces and most middle class had dishes that were made from this technique. These pots were traded heavily throughout Europe and the Middle East. Egypt used to use bisqued pots, fill them with water and leave them in rooms to cool the temperatures down in their dwellings. Some of their famous jewelry they wore was a bluish clay that was called “Egyptian Paste” which was formed into beads, figurines, bangles and inlay. The clay had several chemicals within it, that when it was fired (low temperatures) a blue glaze would form on the outside of the object. When the French first started their explorations of Egypt years ago, when they found these beads, they first called in Faience because the color was so similar to the Faience-ware that Italy made in the 1300’s.

So, depending on where your persona is from, they may have went to a temple that was decorated from the ground up with brilliantly glazed tiles or perhaps they had a tea set of cobalt across white porcelain. Perhaps they were traders or drank ale from an earthenware jug that a monk in a Monastery used. No matter what they did, they probably used clay in one way or the other, just as we do still today. 
 
  
Books Used for This Article: 

“Pottery Decoration” by Thomas Shafer 

“The Craft and Art of Clay” by Susan Peterson. 

“Maiolica, Delft and Faience” by Giuseppe Scavizzi 

Websites: 

The Raku Museum in Japan: http://www.raku-yaki.or.jp/ 

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