Shiny Pottery Without The Glaze!

Roman red gloss terra sigillata bowl with relief decoration
Photo from Museum Römerhalle Bad Kreuznach

Terra Sigillata

After reading about burnishing recently I researched the technique even more and came across Terra Sigillata which literally means 'clay with little pictures'. This definition makes sense if you look at many of the early pots made using this technique which feature figures in relief. However later pots similarly described do not contain figures. So Terra Sigillata has come to be known as pottery manufactured with surface slips which when fired produce a glossy surface ranging from a soft lustre to a brilliant glaze-like shine. Samian ware is also sometimes used to describe all varieties of terra sigillata including undecorated ware.

The history

Ancient Greek pottery neck amphora showing a swordsman.

Image Courtesy of Marie-Lan Nguyen

Most well known for its use in ancient Greek ware Terra Sigillata now describes specific types of plain and decorated tableware made in Italy and in Gaul (France and the Rhineland) during the Roman Empire. These vessels have a range of glossy surfaces and are often found in their characteristic colour range of pale orange to bright red.They were produced in standard shapes and sizes and were manufactured on an industrial scale and widely exported.
The sigillata industries grew up in areas where there were existing traditions of pottery manufacture, and where the clay deposits proved suitable. The products of the Italian workshops are also known as Arretine ware, and have been collected and admired since the Renaissance.

What is a Sigillata slip made of?

Refined Kaolin particles

Terra Sigillata, is made up of finely separated clay particles in water. The clay particles are mostly composed of kaolinite crystals which have a flat plate-like structure.  These particles therefore have a high width to height ratio, called the aspect ratio making it easy for them to fit together in a stack just like a pack of cards.The platelet however are tiny and at less than 2 microns wide can only be viewed using at high magnification microscope. To put this in perspective a human hair measures approx 70 microns in diameter-35 times the size!.

How Does it Work?

When the slip is applied to the surface of a clay article as several very thin layers, the flat plate-like particles align naturally to give a smooth reflective finish. The application process is critical as applying one thick layer is likely to cause the layer to crack as it dries and shrinks. The slip can be successfully applied to leatherhard or fully dry clay. However the best results are reported as being by applying to it to dry ware that has had the surface roughened using 120 grit sandpaper.

For a shinier appearance a quick polish of the surface with a piece of chamois or plastic film or even with a finger tip is effective. This increases the fraction of platelets laying flat on the surface thereby creating increased reflected light.

How does this differ from burnishing?

Polishing and burnishing can give a highly reflectively surface finish but it is a highly labour intensive process. It requires the potter to compress the clay with a polished rock or the back of a spoon in small circles for hours on end until the whole surface has been compressed. This process causes  the clay platelets on the surface to lie flat, while all the other coarse particles are pressed down into the surface. However it creates a very smooth, highly reflective surface.

In contrast, Terra Sigillata avoids the laborious polishing process by naturally laying down a thin layer of aligned clay platelets. Minimal polishing is required to achieve the same high shine as hours of burnishing.

Making the slip

You can make terra sigillata slip from almost any raw clay or clay body that contains kaolinite. However, only a portion of the starting material will contain sufficient fine clay particles to make a good Terra Sigillata. It is therefore important to use a separation process to split the 'good' clay from the 'bad'. This involves first mixing the clay then allowing it to sediment before decanting off the good material.The yield and performance of the slip will be influenced by the particle size of the clay. Therefore in general finer starting clays produce better slips and yield.

Details

The first step is to make a highly fluid de-flocculated suspension of the clay of SG 1.15. A mix of sodium silica/soda ash deflocculant and water is used. After sedimenting for approx 20 hours the ultra fines are decanted off to be used to produce the slip. The suspension at this stage is very watery and needs to be concentrated by evaporation or gentle heating of slip. Approximately 10% of the initial starting material suspension will remain to be used as slip.The slip needs to be approx SG 1.15 for best application.

Applying the slip

Application is made to the dry clay body by using a wide, thick soft brush heavily loaded with slip. Long flowing strokes should be used and drips should be avoided. if a drip appears remove it immediately with your brush. Work around the piece, building up thin coats until I the surface begins to conceal the sanded texture. If available a potters wheel can be used to give an even application. Overall, it needs a very fine coat of slip to avoid cracking and peeling of the layer.The success of this process is a matter of experience-as different slips require layer thickness for optimum effect.

Polishing of the applied Slip Surface

As soon as the the slip layer looks touch dry the surface is polished with a piece of grocery bag plastic or soft material. Amazingly the surface should develop a bright shine in just one polish.

Firing of the slip applied ware

Like burnishing, the terra sigillata surface needs to be low fired for best results but this depends on the clay slip and the underlying body used. Whilst a true burnished surface is recommended for firing at less than  cone 012 (875C), a terra sigillata-coated surface lightly polished can sometimes be fired as high as cone 02 (1125C).

Red terra sigillata also changes colour as well as gloss as the temperature is increased. Starting with orange red then brick red, it will finally turn red-brown before fusing due to the high iron and flux content.

Other clays like stoneware, ball clay and china clays will give white to a light tan depending on their source and chemistry.

Colouring of the Terra Sigilatta

Fine oxides or finely ground ceramic stains can be mixed with the slip to create a wider range of fired colours. However in general the greater the addition of stain the lower will be the gloss on the finished product. Best practice requires the stains to be thoroughly dispersed using a ball mill process. However very finely divided oxides like copper carbonate or cobalt carbonate can be added in small quantities without significant loss of shine.

Summary

Clearly the making of Terra Sigilatta is a skilful but labour intensive process. The decanting process is critical to obtaining the highly decorative glossy finish. However the quality of finish with the soft buttery feel is worth the effort. Indeed many alternative effects have been  obtained using the sigilatta slip in underglaze or combination with other potting methods. It still amazes how the ancient potters developed such sophisticated pottery effects over 2000 years ago. Modern pottery continues to learn from the past by application of our  greater scientific understanding! Long may it continue!

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Burnishing unfired clay pottery

Burnished ware by David Greenbaum

I recently came across the term 'beeswax pottery' and wondered what it meant. I discovered that it was a form of burnishing clay pottery to give it a smooth attractive mainly waterproof finish. Previously, to me, burnishing was just a term for the polishing of gold decoration used for the decoration of pottery.

It reminded me that you never stop learning with pottery. It is such a wide subject which continues to grow as new techniques are invented (or old ones re-invented!).

 History of clay burnishing 
Many ancient potters used burnishing to make their pottery harder and more waterproof before they discovered the use of glazes. Nowadays, modern potters choose to finish their work by burnishing because of the subtle, but beautiful finish achieved using this method. A burnished pot often has a soft, tactile quality all its own. However modern potters also need to know that this type of pottery should be used for decorative purposes only and not for ware intended for contact with food or drink.

Health and safety considerations are now a more important part of our modern life!

 So What is Burnishing and how is it done?

Burnishing is basically rubbing the surface of the clay piece until it becomes glossy. To achieve a satisfactory finish it often takes several hours for even a small pot. Skill and practice are required for this technique as it is highly influenced by the state of drying. The best stage to burnish is usually at the later stage of leatherhard. However many potters burnish the piece more than once to achieve the ultimate finish.

Working in very small areas, applying a little lubricant at a time to the piece, rubbing in different directions will gradually create a sheen. Care is needed as sufficient force is needed to compress the surface but not create a hole or flake. After firing the sheen is mostly retained and can be improved by polishing with beeswax or other types of wax.

 Some key factors to consider when using this technique include:-

  Choose your clay wisely
Burnishing requires either a very fine clay body, or fine clay engobe. Clay bodies which contains grog or sand are therefore not recommended for this technique. Low firing clay bodies such as earthenware are also recommended as higher firing bodies can give rough texture after firing.

Choose your shapes wisely
Pots with smooth flowing surfaces are easier to burnish and look so much better when fired. Complex shapes with sharp corners or surface features will be almost impossible to burnish properly.
  
Choose your tools wisely

The burnishing tools you use need to be smooth, hard and easy to hold. As burnishing is a very time consuming process comfort is an important factor and this is a personal thing. However most potters use the backs of spoons or polished stones for this technique. Some potters carry out a secondary burnish using smooth plastic or other materials.

Choose your burnishing oil wisely.
To aid the burnishing process the use of a burnishing lubricant is recommended. The lubricant allows the clay to densify and give an even smoother finish after firing. . Lubricants that are often used include vegetable oils, lard, and water. Although the choice of lubricant is subjective, water is the least recommended as there is a tendency for it to soak into the body or flake the surface as it is pressed.

Firing 
Firing of the ware after burnishing is important and can alter the texture of the surface significantly. Low firing clay bodies appear to work best.

 Post firing polishing 
 Firing gives the burnished ware a lovely, tactile soft feel. In ancient times, animal fat, oil, and wax were often used to make it more waterproof and to restore the pre-firing high gloss. Today, most potters use a  form of wax. Paraffin wax, candle wax, and beeswax, have all been used successfully. By applying the wax to a small area of heated ware and polishing a high sheen can be achieved.  The result is an outstanding piece of decorative ware that often looks as though it has been glazed but feels so different!

If you found this article of interest make sure you read about Terra Sigallata a method for making shiny ware without the polishing stages!

Of course more information and other technical articles on pottery and ceramics can be found at my website  The Potters Friend. Go now to sign up for my free  newsletter.

How to Choose a Pottery Class

The Benefit of Classes

Learning how to make pottery whilst enjoyable in its own right, can be enhanced by professional teaching and sharing of experience with other students.

Classes help people learn quicker and provide the right learning environment to enjoy the experience as well as make friends. This should not be underestimated as many frustrations will become apparent along the way..There are both studio potters who run classes in evenings and weekends as well as local colleges who run part time and full time courses.

Be clear on your needs

One question you need to ask yourself is "do I want to learn the practical skills such as throwing on a wheel or do I want to have a good scientific/artistic understanding?" Knowing this will help define your teaching requirement.

I recently read a debate about when should you call yourself a potter? It was interesting to note that most people shared my view that "you never stop learning in pottery". As pottery making is such a wide subject, you can be an expert in part of it and a mere novice in another area.

Therefore at which point you become expert or call yourself a potter is purely arbitrary.

This point is important as you need to find an expert teacher in the area of pottery in which you want to learn more. 

Choose the right teacher and class

Choosing the right pottery class is not always easy. For example, if you have an interest in learning the basics of  pottery making then joining a class learning about Raku firing is less useful. Similarly if you purely want to learn artistic skills such as hand painting of china as a hobby, there is no need to learn about slip casting of bone china. Clearly it is important to ask the right questions to make sure a class meets your specific needs.

Some helpful links

The following links and brief details of classes may be helpful. Unfortunately I cannot make recommendations as there are so many of which I am not personally familiar. Therefore when making an enquiry please ask for references from previous satisfied clients and ensure that the classes meet your needs etc

Good Luck and enjoy!

Pottery Classes in USA
Directory of Pottery Classes, Courses, Lessons, Events, Workshops, Free Classes, in USA
Pottery classes and Art courses in UK
Directory of Pottery,arts and crafts classes, workshops and painting holidays in Britain and Europe.

More details of individual classes and workshops can be found below:-

Details of UK pottery classes

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

How To Teach Children about Pottery

Make it Fun
You make their first contact with pottery a fun enjoyable experience. Once they have the interest then you might want to add a little practical knowledge. Of course you want your children to be safe so only use safe materials and provide basic hygiene equipment, and instructions such as -wash your hands, and don't put anything in your mouth.

Where should you start?
Most children are familiar with playdo or plasticine. They have probably moulded these into shapes before. So let them use their imagination to form something that means something to them. Air drying or oven bake modelling clay products (suitable only for age over 3 years) similar to plasticine can be used which allow the pieces to be hardened into permanent shapes.

What next?
Once stimulated you might want to demonstrate how to roll a ball and make a sausage of clay and coil it to make a circular shape. Let them experiment making shapes themselves. Once adept at creating coils you might want to show them how to stack the coils to make a bigger shape. Plastic cutters such as used in cookery can be used to cut out shapes from a flattened out clay just like cutting shapes out of pastry.


What about painting colours?
Many of the items once air hardened or oven baked can be painted with acrylic paints. This allows children to learn a painting skill. The use of different size or shape of tip on brushes can help with children of different skill levels or ages. These skills can then be readily adopted and used with ceramic paints as the child progresses to making real pottery.

What about older children?
Older children need more to keep their interest so create a project and set them a challenge of making an item such as a coin tray. The same materials can be used as for younger children.

Alternatively get some real pottery clay and get them used to its feel and how water affects it and allows it to be smoothed or reprocessed when it dries out..  Of course this might become more messy but that's all part of the fun. Learn that large sections of clay crack on drying and why!

Sculpting tools can be used to  allow even more skills to be developed and create a personalisation of the work.

It is important to note that all items produced from the above information should be considered as purely decorative. Under no circumstance should they be used as food contact items.

Real pottery
In order to make real functional pottery special ceramic materials, glaze and colour need to be used as well as firing in a pottery kiln at very high temperatures (greater than 1000C). This requires some specialist knowledge and expertise. Pottery classes would be recommended at this stage to progress in a safe and friendly environment.

Acrylic paints and a domestic oven WILL NOT produce functional pottery.

More information about getting children to work with clay can be found at 'Teaching Tips for clay' Even more information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Art Deco Ceramics

A time of great design or merely time for a change?

Art Deco ceramics are commonly associated with specific designers such as Clarice Cliffe, Susie Cooper and Charlotte Rhead whose striking designs changed the face of modern pottery. However the term covers a much wider range of pottery styles as well as architecture and fashion. But was it truly a time of great design or merely time for a change? Let us examine the evidence.....

The history of Art Deco

Ravel conical ware by Clarice Cliffe
Photo by Leonard Griffin

Art Deco is said to have begun in France in the 1920s and developed internationally especially in Europe and America until the late 1930's. However it was not until the revival in the 1960s that the term 'Art Deco' was introduced. Until that time it was called 'Arte Moderne' or 'Arte Decoritif'. Since that time many modern potteries have developed patterns based around similar principles.
The advent of Art Deco changed the face of pottery in the UK at the time. The bright colours and geometric shapes of Clarice Cliffe especially, was a long way removed from many of the chinese inspired pottery designs that had gone before. However many shapes and designs were influenced by Mexican and Egyptian styles. A revolution in design was in the making! In the UK the popularity was aided by young new designers and and the advent of advertising and to a degree mechanisation. Designer labels grew as a marketing trend and women designers had phenomenal success. It became a necessity for small potteries to find new designs to beat off the threat of imports from Germany and Czechslovakia and Japan.

Clarice Cliffe

Original Bizarre on Athens Shape
Original Picture by Harvey

Clarice Cliffe, probably the name most associated with Art Deco style, was born in Tunstall, Stoke on Trent in 1899. She joined Royal Staffordshire Pottery aged just 17 and briefly studied art at the Royal College of Art in London. Her skill was such that she rapidly became a top designer of ceramics and was probably the first to design both the shape and decoration of UK commercial tableware. Cliffe produced some of the most exciting designs of the times ware adorned with bright colours such as Original Bizarre.

Crocus pattern
Photograph by  Andy Titcomb

Her success resulted in numerous designs being release in commercial volumes between 1927 and 1939. However it was the more conservative 'Crocus' pattern which was regarded as her signature pattern.
Pieces of Clarice Cliffe are now highly collectable and include such striking designs as the conical ginger sifters. Collecting is made easier by the fact that virtually all Clarice Cliffe pieces are clearly marked with her name using a rubber backstamp or litho.

Susie Cooper

Kestrel pattern
From National Museum Wales

Born in 1902 in Stoke on Trent, she entered the pottery industry at A.E. Gray & Co in 1922 and trained under Gordon Forsyth. Brightly coloured abstract geometrics and cubist patterns were her trademark and she developed some stunning designs such as Kestrel and the cube shape galaxy pattern. By 1929 she had left Gray and started her own pottery painting business and this initiated a long and distinguished design career spanning 60 years. Her designs were highly practical with 'fitness for purpose'being a common theme. A black triangular back-stamp with the words Susie Cooper Productions was used until about 1932. After this time a variety of signatures was used.

Charlotte Read

Tube lined plate by Charlotte Rhead
Photo by Chris Bertram.

Born in 1885 into an artistic family in the potteries town of Burslem, Charlotte Rhead studied art at Fenton School of Art. Working for a local company Wardle and Co she learned the skill of tube lining. It was this skill and the influence of her time at Wood and Sons which set her career apart as a designer. Later in 1926 working for Burgess and Leigh she mainly produced ornamental or luxury pieces using her tube lining skill.

Other Art Deco ware

Shelley Vogue shape cup and saucer, designed by Eric Slater 1930

Harmony Art Ware ginger jar - Eric Slater 1932

The Shelley Family was a highly acclaimed producer of Art bone china in the art deco style. Apart from the elegant 'vogue shape' it produced highly decorative vases such as
'Harmony Artware'. Eric Slater was the designer responsible for many of the hugely successful designs.

The Wedgwood family also produced a range of ware in art Deco style. Using a range of designers such as Keith Murray, Skeaping, Makeig-Jones, and Ravilous they continued to create outstanding designs throughout the 1930's. Makeig-Jones in particular changed the image of Wedgwood ware with her inspirational 'Fairyland Lustre' range of patterns.

The Modern Era

Wedgwood Jasper Conran

Clearly many of the Art Deco designs of early period have inspired post year 2000 patterns. Classic, timeless and elegant, almost all top pottery brands have some element of Art Deco in their range. Wedgwood, Portmeirion, Dudson and Steelite each include high coloured decorative patterns or striking geometric shapes. This is not by accident and I can only conclude that the Art Deco period was truly a time of great design!

I would love to hear your comments?

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

How to make a Pottery Glaze

The Glaze Recipe There are literally thousands of different types of glaze depending on the clay body used and the firing cycle and condition. A virtually unlimited number of colours, textures and designs are also possible. Applying more than one glaze to the piece just multiplies the possibilities. Each glaze needs its own specific recipe, making process and testing for optimum performance. However for ease of understanding I shall give the recipe and outline process for a transparent glossy glaze firing at 1050C. A typical glaze recipe includes: Borax Frit China Clay Transparent borax frit               90 parts China clay                                10 parts Water                                       50 parts Glaze milling (particle size reduction) In order to melt a glaze rapidly and produce a high gloss finish it is necessary to reduce the particle size to a powder and ensure that it is well dispersed in water. For this to be achieved the particles of the frit and clay are ground to an average size of 5 microns-less than 1/10th the size of a human hair. Overall a distribution in the range 60-70% less than 15 microns is targeted. Glaze Mill Ball mills are traditionally used to grind the materials to make the glaze. The ball mill is a metal cylinder lined with hard alumina or silica blocks. The mill is filled with graded ceramic balls with a max size of 5cm. to approx 50% apparent volume of the internal space. This allows efficient grinding of the glaze. The glaze materials occupy approx 1/3 the volume. The glaze is sampled after set time periods eg 12 to 20 hours until the required particle size distribution is achieved. Glaze Processing Once the average particle size is achieved the glaze slurry is poured out of the mill into a storage vessel via a coarse sieve. This removes large glaze particles and remnants of the grinding balls from the glaze. Typically a 60 mesh sieve is used. The glaze is then processed further by passing the slurry over thro a fine sieve typically less than 100 mesh and a strong magnet. The magnet can be rare earth magnets or electromagnets. This cleansing process removes more of the coarse residue and contaminants that can give faults after firing. Glaze Quality Controls A few simple tests are used to assess the quality and suitability of a glaze for use and include:- 1. Glaze appearance after firing- by glazing a tile of standard body and firing 2. Particle Size measurement and distribution 3. Solids content of slip = slip density 4. Slip fluidity = Slip viscosity Additional tests may be carried out depending on the end use. For example for hotelware the physical and chemical durability may be assessed. Rheology Control The glaze slip rheology is controlled according to the application method required eg dip, spray or brush etc. This is achieved by control of density, viscosity and thixotropy. A torsion viscometer and density can are often used to measure and control these key properties of the slip. Addition of binders and other chemical additives are usually necessary to achieve the optimum properties for specific application methods. Supply and Packaging; Glaze can be supplied in containers suitable for use from 500ml jars for brush on glaze, 5 to 50 litres for dip glaze and 5 to 1000 Litre tanks for spray glaze. For industrial use tankers containing 10000 litres may even be used. However for overseas or long distance supply the glaze is often supplied as a dried powder. In this case the user needs to mix up the glaze and control the slip characteristics themselves. More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

The Elusive Red Pottery Glaze

Symbolism of Red

Red is one of the most popular colours to be used worldwide. The color red is associated with lust, passion, love, beauty, and danger. In Asia it is a symbol of courage, loyalty, honor, success, fortune, fertility, happiness, passion, and summer.

Consequently many types of asian pottery including the beautiful chinese red glazes of the Sung Dynasty and the exquisite Japanese Imari porcelain feature red as the main colour.

However in more recent times the demand for mass produced red pottery of high intensity and consistent colour has created a real challenge for ceramic engineers involved in pottery manufacture.

Japanese Red
Imari porcelain is the name for Japanese porcelain wares made in the town of Arita, in the former Hizen Province, northwestern Kyūshū. They were exported to Europe extensively from the port of Imari, Saga between latter half of 17th century and former half of 18th century.

Photo of Imari by George Le Gars

Though there are many types of Imaris, Western Europes conception of Imari is associated with the type of Imari produced and exported in large quantity in mid-17th century. This type is called Kinrande and is coloured porcelain with underglaze cobalt blue and onglaze red and gold.

The blue is rich in colour and hue and is based on a cobalt containing pigment. The red colour, however, whilst remarkably bright and interesting is not such a clean hue and is produced using iron oxide or iron based ceramic pigments.

Iron ochres and natural red clays are some of the earliest pigments used by man and continue to be used today particularly in hand crafted pottery of rustic nature.

Rouge Flambe
Similarly many of the early ceramic red colours and glazes used on European pottery were not always pure in colour and were based on copper or gold in colloidal form. These colours were used to copy original Chinese patterns and glazes perfected in the 18th century.

Rouge Flambe by Royal Doulton Co

Interest in reproducing flambe glazes began in about 1855 in France but soon spread across Europe, particularly to England and Germany.

In Britain, the Staffordshire potter Bernard Moore used experimental and highly accomplished red flambe glazes on Chinese-inspired shapes to wonderful effect. Requiring a special glaze formula, firing cycle and condition they were expensive to manufacture and difficult to reproduce.

Shown here is a vase made by Royal Doulton decorated with the spectacular Rouge Flambe glaze.

The Challenge of Pillar Box Red

Red Pillar Box by Ian Britton 
FreeFoto.com

The development of a reproducible pillar box red glaze and decoration has been an elusive challenge for potters and ceramic engineers through the ages.

In particular the large scale development and manufacture of pillar box red colour and glaze for pottery is believed to have taken over eight thousand years to achieve. It was not until the twentieth century that true pillar box red glazes and onglaze colours became widely available for decoration of pottery.

Cadmium Sulpho-Selenide Red Glazes

Red glazes and colours based on cadmium have been available for about 50 years. The early glazes and colours of this type depended heavily on cadmium being added to the glaze as a pigment mixed crystal Cadmium sulphoselenide (CdSSe). However glazes of this type lacked temperature stability above approx 800C.

To overcome this the cadmium was added to the frit batch and subsequently melted into a glassy state. In many cases the frits also contained lead, sulphur and selenium. This type of glaze required firing in a specific way to achieve optimum results. The firing time and the kiln atmosphere were both critical. The best results were obtained using a short firing cycle to a peak temperature of approximately 1000C. Good air circulation in the kiln, and a good separation of pieces were also recommended. Ideally Cd/Se fritted glazes should be fired separately from other types of ware, because fumes from other coloured glazes can affect the colour achieved.

First generation Zircon/ Cadmium Red Glazes

Actual Red

Target Red

In the 1970s ceramic engineers in Europe developed a new generation of red colours and glazes. These were totally different in nature as they were based on a zircon encapsulated cadmium pigment. These were patented in 1973 by Broll et al of Degussa.

Briefly encapsulation  means that at microscopic level the cadmium is surrounded by the zircon crystal. This gives two major advantages. The pigment is more temperature stable up to 1200 celsius and more chemically stable thus giving lower cadmium release after firing and exposure to acids. These types of red glaze could be used on a variety of firing schedules and were infinitely more flexible in use.

However these pigments had a serious drawback which limited their widespread use. They lacked intensity and consequently needed high pigment loading to give any degree of colour saturation.


Second and third generation Zircon/ Cadmium Red Glazes

Red Vase by Newland Pottery BV

In the last 20 years or more the encapsulate type of pigment has been developed further to the stage where intense pillar box red coloured glazes (see target above) are now possible. These pigments have allowed more stable sanitaryware glaze colours to be produced where high temperatures in excess of 1250C are used. In addition they are suitable for use in a range of glaze and onglaze colours as they are mixable with other non cadmium based colours.

China is the major manufacturer of these types of pigment as they have proven to be a lower cost supplier of intense encapsulate pigments.

The challenge of the stable pillar box red glaze now appears to have been met by ceramic engineers. The  stable cadmium encapsulate pigment is being used by most pottery manufacturers and appears to meet current legislation in many parts of the world. However cadmium is still an emotive word for many being considered a toxic element in much the same way lead. So who knows? Will the journey to find a new pillar box red start all over again? What do you think?

This article was inspired by the recent publication of  a book entitled THE DEFIANT RED by my friend the highly respected ceramic expert Leen W Baaij.

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

How to Buy Your Ceramic Dinnerware

Fashion is a strong reason to buy

For the discerning shopper selection of dinnerware is primarily based around fashion. In today's fast moving world, where casual dining has become the norm, our dinnerware often reflects our taste in food or the environment in which we use it. For example Mexican food might well be served in brightly coloured dishes decorated with peppers, spices and other vegetables reflecting the type of food we might eat..However the technical issues are a lot harder to assess and should also be valued highly!

What is ceramic dinnerware?

The word ceramic was derived from the greek word 'Keramos' meaning 'earthen vessel'. The word has now been applied to a wide range of products from terracotta to the finest bone china. Dinnerware and tableware are just two of the categories often used by stores to describe the end use of this range of ceramics.

What type of ceramic is it?

Many types of ceramic are on display in shops and stores. These include terracotta, earthenware, stoneware, porcelain and bone china.

Often it just says china on the box but this means nothing as it is just another broad term implying it is a ceramic! But we already know that!

So just how do we identify the different types of pottery?

One way is to look at the colour of the body under the shiny glaze. The best place to do this is under the foot of the item as this is often unglazed. In order of pure whiteness the following is a generalised guide to the colour.

Terracotta bright red to red brown body colour

Stoneware pale brown to buff colour

Earthenware ivory to off white

Porcelain off white to blue white

Bone China creamy pure white

Bone China and Porcelain

Porcelain and bone china can be more easily differentiated from the rest by their translucency. This means that they they let light transmit through the piece. If you hold a delicate piece of bone china or porcelain up to the light, and wave your hand between the plate and the light, you can see a shadow of your hand through the piece

The technical stuff

What does it all mean?
Once you know the type of ceramic you have some idea of the technical properties. Firstly it is a guide to the strength of the piece and means resistance to chipping,cracking and breakage. Secondly it is a guide to the cost. High quality bone china and porcelain manufacturers use highly refined materials and processes to 'design in' the whiteness,translucency and strength required by consumers. Consequently the cost is higher. However because of the inherent strength you might expect this type of pottery to last longer in use!

As in life things are never quite so simple. The manufacturers of other types of dinnerware (terracotta, stoneware,and earthenware) compensate for their lack of inherent strength by making chunkier pieces. All types of ware can be highly decorated with colour so this is not the differentiator.

So the shopper has a choice of chunkier less white designs or whiter more delicate designs!

What about dishwashing?

The chemical resistance to acids and washing detergents is also worth considering. Generally higher fired glazed tableware such as porcelain and stoneware have a higher intrinsic chemical durability and are 'unleaded' but this is not always the case.
Top brands now indicate their testing to BS or FDA standards and indicate their quality by labelling with 'dishwasher safe' and 'unleaded' or 'lead-free'. The Kite mark is also used as a sign of quality manufacture in the UK manufacture. The astute shopper therefore needs to look for these labels in determining value for money.

Fashion and technical performance are both important
In summary,shopping for dinnerware can be an enjoyable experience! Armed with a little technical knowledge it can be so much easier! Give at least equal weighting to to the technical performance as to the fashionable design in choosing your ceramic tableware.

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Cheadle's Pugins Gem

One of my favourite places

Once upon a time in a small market town in Staffordshire, England, an amazing church was built by a not so famous architect. The same man also designed the Houses of Parliament and Big Ben. St Giles RC church, because of its beauty and spectacular gothic architecture, became known as Pugin's Gem and has featured on both the BBC and Channel 4  in recent years.

That man was Augustus Welby Northmore Pugin, and he is now regarded as being responsible for the revival of Gothic architecture in the UK in the nineteenth century. In a recent BBC documentary, his influence on architecture was likened to that of Darwins influence on science.

2012, was the Bicentennial of the birth of Pugin and it was celebrated in style in Cheadle, a relatively unknown town that sits on the edge of the beautiful Staffordshire Peak District. A series of events,workshops, tours and exhibitions were staged throughout the year based around the church, the nearby Pugin Centre,and other local Pugin buildings. The legacy is the Pugin discovery and heritage centre which is sited at the centre of the High St.

The church itself is open to visitors most days and really should not be missed. Put a coin in the slot, sit back and be amazed as the church  is revealed in all its splendour. You will not be disappointed. To appreciate the church in full obtain an audio guide first from the Pugin Centre and allow it to guide you around the features of the church.

If you are travelling close to Staffordshire Peak District this year why not spend a little of your precious time to visit the not to be forgotten Pugin's Gem. There's also a chance to discover more of the Secrets of Cheadle, which lies only a few miles from Alton Towers resort and the scenic Churnet valley with its Steam railway and excellent country walks.

To find out more about Cheadle and how to get there why not visit the Cheadle,Staffordshire website Cheadle Staffordshire

2012 The Year of the Small Business?

After the doom and gloom of 2011, a year when banks, the public sector, big business and especially retailers have suffered, perhaps 2012 is the year for the small man. The year when the public begins to recognise that what they have locally really is worth keeping. And that should include the local butcher, the local tradesman and the local potter.

Yes the local potter!

I was fortunate to meet a number of innovative potters at the 2011 Ceramic Festival in Stoke on Trent, England. Despite the current climate they continue to create innovative designs and concepts.

One such company with years of experience in modelling and design of unique ceramic wares is Sculpta Ceramics. The expertise of individual potters like this should not be underestimated. Designing unique wares for children, and local heritage are all part of the range of products from local man Nathan.

Another local artist Alison Morgan is the creator of Cityscape Ceramics, a unique range of ceramic art. Each piece is inspired by an iconic skyline and features well known and loved landmarks.

During my visit to the festival I even managed to buy a ceramic bottle kiln jar to add to my collection.

So next time you want that special present or gift don't overlook your local potter. They may not be on the high st but many will be only too pleased to show you their wares!

More information on pottery and ceramics can be found at my website http://www.pottersfriend.co.uk Go now to sign up for my free newsletter.